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Frankenstein boat for the poor cruiser...will it sail?


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Hi,

I am already quite far in the planning stages of building a liveaboard cruising boat. But the budget I have to build it is miniscule. About the amount many sailors spend on their mast alone. Due to this limitation the boat has to be less than ideal and unconventional. I was looking at used boats but prices have only gone up. Plus I would not feel safe on a very old boat. And in use it is probably less cheap....repairs will add up quickly.

So I think I have to build it myself.

My first decision is that it has to be light weight. On a light weight vessel everything can be smaller. Smaller sails, smaller mast, smaller engine....everything gets cheaper. (unless you start with carbon) Single hulled boats have more resistance, more ballast so they need a big rig and engine. So it has to be a multihull. I settled on a 40ft strip pauwlonia wood strip planked trimaran. With a plank thickness of 2 cm and fiberglass/epoxy inside and out and extra fiberglass below the waterline It works out remarkably light. In my first estimations the boat shell will weigh around 1600 or 1700 kg without fittings and mast. 

This enables a small sail plan, smaller outboard, smaller rudder and dagger board etc. The smaller sail plan will eliminate the need for winches and massive blocks. To join the three hulls I designed a glass fiber leaf spring system. Basically a very large version of the new suspension system for mountain bikes.

Lauf Carbonara Fat Bike Suspension Fork - Glory Cycles

 

This connection is light weight because it doesn't rely on rigidity. It also puts less stress on the hull. Another plus is that it should even out the ride in hull-length frequency cross waves. Because each ama bow and stern can move up or down about 25cm.

But now I am stuck on what to do with the rig. I cannot afford a regular mast. I need something I can make or repurpose myself on the cheap. My first thought was lamp posts, but locally (Thailand) I have only been able to find thick walled steel light poles weighing 235KG for 12 meters. If I keel step I have 10m left so I would need a two mast arrangement to get enough sail area. Almost 500 kg of mast on such a light boat seems absurd. I have looked into wood, diy glass fiber, crab claw sails with surf masts.... None of it seems right.

While studying all existing and forgotten sail plans I stumbled on the sprit sail. I even forgot about the Optimists! The longest light weight spars I can get are only 6 meter. What if I make optimist style sprit sails out of 6m alu tubes? Each sail can be around 16M2. If I make the boat quadplane rigged, so 4 masts, 2 on each ama, I will still have a sail area of 64m2 which should be plenty for a light weight trimaran. The positives are that it will be insanely cheap, easy to handle and very safe (try capsizing that!) Especially for cruising it has a lot of redundancy. Loosing a mast wouldn't be a biggy, hell you could even carry a few spares!

BUT....Would it sail? I would guess in strong winds it would go as a locomotive and only in extreme conditions would you reduce sail by removing the sprits. Removing the sprit and tying down the sail almost halves the size. It becomes a tiny bermuda sail. I also read that sprit sails point very well and outperform bermuda sails on a reach. But in lighter air, how much would I suffer? With such absurdly low sails and lower wind due to wind gradient how much wind would I need to get going?

The boat doesn't need to be fast or sexy.....it should just sail from point A to point B safely and at least as fast as your average monohull.

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uh huh... that some kinda IUD?

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idk shit about aerodynamics - but one of the interesting features of sticking an airfoil into a floating hull is that it moves around a lot. choppy waters tend to play havoc with airflow. and from what I can tell, you are designing towards a raft-like trimaran. So, what's it like sticking a rig in a raft?

its kind of interesting that you choose a suspension fork as your model (btw - I guess that fork represents a rather impressive feat of engineering and fabrication) - but suspension tends to kill performance. I guess you look at most sailboats, they are aiming for hull stiffness, not flexibility.

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What is cheap? A safe 40 footer that doesn't need any expensive repairs..... So far the total materials cost for my trimaran including engine, AIS, radar, wind steering, anchors etc. is between 40k and 50k USD. I can get many cheap materials here and directly from China. If I buy a 1980 used monohull for that price I will end up with lots of maintenance, very old navigation equipment, old sails, old rigging.....

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12 minutes ago, floater said:

idk shit about aerodynamics - but one of the interesting features of sticking an airfoil into a floating hull is that it moves around a lot. choppy waters tend to play havoc with airflow. and from what I can tell, you are designing towards a raft-like trimaran. So, what's it like sticking a rig in a raft?

its kind of interesting that you choose a suspension fork as your model (btw - I guess that fork represents a rather impressive feat of engineering and fabrication) - but suspension tends to kill performance. I guess you look at most sailboats, they are aiming for hull stiffness, not flexibility.

I don't think the stiffness of modern boats is the goal. I think the goal is light and strong. The only way to make something light very strong is to use very stiff materials. There are outrigger boats with deliberately free swiveling ama's to prevent plowing in to waves.

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2 minutes ago, LongJohn said:

I don't think the stiffness of modern boats is the goal. I think the goal is light and strong. The only way to make something light very strong is to use very stiff materials. There are outrigger boats with deliberately free swiveling ama's to prevent plowing in to waves.

yes, but the rigs aren't in the amas.

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35 minutes ago, Reference said:

Have you ever been on a sailboat before?

In my youth I sailed Optimists and then Laser. My experience on larger boats is very limited...just a passenger. I know it is abnormal to build a large boat without lots of experience. But I like taking risks. Life is short, better make it an adventure.

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18 minutes ago, floater said:

yes, but the rigs aren't in the amas.

I know they usually aren't. But they could. Until someone thought of a biplane rigged cat they would say the masts aren't in the hulls, they are on the bridge.

And on proa's they sometimes are on the ama. Granted it shouldn't be on a low buoyancy ama. 

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I thought you guys were anarchists? But in stead all I hear is you should do what everybody else does. Play it safe....be normal, stay on the beaten path. I think this forum should be re-named to Sailing Conformity  :-)

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13 minutes ago, notallthere said:

Why not sleeve the 6m alum tubes you have available to make a 12 or 18m long mast(s)?

 

Hurray! The first constructive poster. Thanks. I'll play with the idea. I am not sure if this aluminium is suitable for that. I know there are different grades and have to look into this. I was kind of hoping to be able to go with an unstayed mast, like some do with Junk rigs.

But I would also like someone's educated opinion on having multiple smaller sails. I know a tall rig is better but when cruising how bad would it be? Less than optimal or total crap? I have seen Wharram cats with quite low rigs cruising in far away places....

I remember seeing a Youtube video ages ago of a catamaran with a hole bunch of windsurfing sails on it. That thing was going but it there was quite a bit of wind.

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13 minutes ago, LongJohn said:

I thought you guys were anarchists? But in stead all I hear is you should do what everybody else does. Play it safe....be normal, stay on the beaten path. I think this forum should be re-named to Sailing Conformity  :-)

Fish Food? Is that you?

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15 minutes ago, LongJohn said:

I thought ..,

Thailand? We’d love to see the required wife/gf/ho tit’s now. That is the rule here. 
 

Have you ever lived on a boat? Take a look around a Thai harbor to see what the sane and practical people are living on.  Fisher-persons, cruisers, drunks. You will notice their boats share no similarity with your goofy dreams. 

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2 minutes ago, Borracho said:

Thailand? We’d love to see the required wife/gf/ho tit’s now. That is the rule here. 
 

Have you ever lived on a boat? Take a look around a Thai harbor to see what the sane and practical people are living. Fisher-persons, cruisers, drunks. You will notice their boats share no similarity with your goofy dreams. 

There are no rules in Anarchy bro.

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9 minutes ago, LongJohn said:

There are no rules in Anarchy bro.

Okay. If you say so. Please continue with you stunning discourse on boat design. I am particularly interested in your goals related to the popular sailing ratios: SA/D etc. most other sailors here will be thrilled with your ideas regarding revolutionary ideas on anchor design and electrical crimper selection. 
 

But, seriously, we are quite interested in the particulars of the Thai girlfriend that you dream of attracting to your yacht. 

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55 minutes ago, notallthere said:

Why not sleeve the 6m alum tubes you have available to make a 12 or 18m long mast(s)?

 

The aluminium I can get here is 6063. Same type used for window frames. Not suitable for structural elements.....like tall masts.

QUOTE: AL 6061-T6 has a higher yield strength and fatigue strength when compared to AL-T6 6063. 

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Woukl

2 hours ago, LongJohn said:

What is cheap? A safe 40 footer that doesn't need any expensive repairs..... So far the total materials cost for my trimaran including engine, AIS, radar, wind steering, anchors etc. is between 40k and 50k USD. I can get many cheap materials here and directly from China. If I buy a 1980 used monohull for that price I will end up with lots of maintenance, very old navigation equipment, old sails, old rigging.....

You could get a real usable boat for $50k :rolleyes:

Would you come flying with me in an airplane made from weird random shit and a weird design by an amateur who has zero experience with airplanes?

Would you move in next to a nuclear reactor built by some guy whose experience with power plants is jump-starting a car once?

There is a reason boats are made the way they are ;) Please at least remember a frying pan, cheese, bean sprouts, and a book about the 4th Mode. That way you will have a chance, maybe not a good one, but without those essentials there is no chance whatsoever.

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2 hours ago, LongJohn said:

If I buy a 1980 used monohull for that price I will end up with lots of maintenance, very old navigation equipment, old sails, old rigging.....

Versus if you build a boat from scratch, you'll still have to buy navigation equipment, rigging, sails....

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2 hours ago, LongJohn said:

I don't think the stiffness of modern boats is the goal. I think the goal is light and strong. The only way to make something light very strong is to use very stiff materials. There are outrigger boats with deliberately free swiveling ama's to prevent plowing in to waves.

 

No, there aren't. There have been a few trimarans with amas that could rotate around the boats Y-axis, the bearings were carefully built to prevent them from "swiveling freely".

It's turned out that wave-piercing hulls that are as rigidly held as possible are a lot faster and safer.

Also, be careful of mistaking "strong"... as in something that can withstand very large loads without breaking... for "stiff" as in something that can withstand very large loads with minimum deflection.

Study the designs of James Wharram. It sounds like you are trying to re-invent the wheel.

FB- Doug

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Cheap - Light - Durable

Anarchy or not... You can only pick 2!

 

Wasn't the Tin Can recently converted to cruising and up for sale and probably way under budget? 

2 cm thick wood on a multi seems a tad overkill....

Why not just launch a giant kite, no rig needed!!

 

My favorite is the multiple rigs on amas that flail about! How fast would it shake itself apart?

 

 

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this one has potential, we should support him, troll or not, to see how far it gets. personally I'm having few reservations about this revolutionary bicycle derived hull joining contraption, way over my head it is, can't see how earth this would work in first place, let alone coping with marine loads, but that's just what makes it fun, remember our dear old friend the Harlisaki-man, and others, for spirit I'd invite the LongJohn to consult one of the true heavyweights on free yottie thinking, to be found at :   how to imagine your ultimate yot and if all else fails, contact Brent Swain who will inform you -for a minimal fee- how to get round things, of course Bob P. could also give you a good lecturing but that comes at a price

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31 minutes ago, Albatros said:

this one has potential, we should support him, troll or not, to see how far it gets. personally I'm having few reservations about this revolutionary bicycle derived hull joining contraption, way over my head it is, can't see how earth this would work in first place, let alone coping with marine loads, but that's just what makes it fun, remember our dear old friend the Harlisaki-man, and others, for spirit I'd invite the LongJohn to consult one of the true heavyweights on free yottie thinking, to be found at :   how to imagine your ultimate yot and if all else fails, contact Brent Swain who will inform you -for a minimal fee- how to get round things, of course Bob P. could also give you a good lecturing but that comes at a price

I think we should just steer him to the HotRod Catamabarge/rutter thread. It's already been so-o done.

FB- Doug

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5 hours ago, Borracho said:

Thailand? We’d love to see the required wife/gf/ho tit’s now. That is the rule here. 
 

Have you ever lived on a boat? Take a look around a Thai harbor to see what the sane and practical people are living on.  Fisher-persons, cruisers, drunks. You will notice their boats share no similarity with your goofy dreams. 

Even the non sane and practical.

Still he uses the obligatory 'bro' so that will help with the gf.

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6 hours ago, Borracho said:

Thailand? We’d love to see the required wife/gf/ho tit’s now. That is the rule here. 
 

Have you ever lived on a boat? Take a look around a Thai harbor to see what the sane and practical people are living on.  Fisher-persons, cruisers, drunks. You will notice their boats share no similarity with your goofy dreams. 

All bars in Thailand are closed currently due to COVID...  so unlikely the OP can get a picture of a 'Thai Girlfriend' for us, unless he knows of the bars that you can sneak in to...  But given his budget, I doubt he has the kind of cash required where the bar owners will let you do that.

 

@LongJohn

image.thumb.png.1f838b294f9935a011daeeb0eed90e32.pngIf you're in Jomtien area, cruise around the beach next to Ocean Marina.  There are many charter catamarans sitting and rotting due to no Chinese tourists allowed into Thailand...  One of them could be had for next to nothing.   Sorry for poor resolution, taken from my condo in 'panorama' mode.

The red circle one is probably right up your alley.  Just rip off the top deck, add Optimist rigs, good to go.  The yellow circle one dragged and sank recently during the last large Southwest Monsoon blow we had.   Might be able to get that for cheap also.  :P  :P  :P 

 

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10 hours ago, LongJohn said:

I settled on a 40ft strip pauwlonia wood strip planked trimaran. With a plank thickness of 2 cm and fiberglass/epoxy inside and out and extra fiberglass below the waterline It works out remarkably light. In my first estimations the boat shell will weigh around 1600 or 1700 kg without fittings and mast. 

What's your budget like? My understanding is that Paulownia is very expensive. I found one source of 6 1.25x6x96" planks for around $300. That's a lot of money, maybe it's cheaper in Thailand but given that it's a premium wood in Japan I suspect it's expensive there, too. I like the idea of you building something easily driven, but I don't think your suspension idea is going to work. I think you'll find all that flexing will cause more problems than it will solve, including not providing a good base for your shrouds. Eric Sponberg used to have plans for building a wood and fiberglass free standing masts for the do it yourselfer which would get rid of the shroud requirement:

wood-epoxy-wingmast

Light boats in heavy seas need to be well designed and well driven or you're going to find yourself in danger, another reason to not use a suspension system for your boat.

That said, I think you are providing your own confirmation bias when you say "Plus I would not feel safe on a very old boat. And in use it is probably less cheap....repairs will add up quickly."

That is entirely dependent on the "old boat" you choose. I had a 1980 Freedom 40 CK that cost $65k and with the exception of the sails, it was pretty inexpensive to run and to maintain. After I sold it, the new owner eventually sailed it across the Atlantic to England. You can disparage the lack of "anarchy" here all you want, but the people who have commented so far have watched a number of well-meaning projects like the Tin Can and the Flyin' Hawaiian and others come to doom and unmitigated failure. Dream all you want but history says you will grow old and broke trying to finish a project like this. Go ahead, go out and prove us all wrong, but at the end of it, please be honest on how much it really ended up costing.

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10 hours ago, LongJohn said:

Hi,

I am already quite far in the planning stages of building a liveaboard cruising boat. But the budget I have to build it is miniscule. About the amount many sailors spend on their mast alone. Due to this limitation the boat has to be less than ideal and unconventional. I was looking at used boats but prices have only gone up. Plus I would not feel safe on a very old boat. And in use it is probably less cheap....repairs will add up quickly.

So I think I have to build it myself.

My first decision is that it has to be light weight. On a light weight vessel everything can be smaller. Smaller sails, smaller mast, smaller engine....everything gets cheaper. (unless you start with carbon) Single hulled boats have more resistance, more ballast so they need a big rig and engine. So it has to be a multihull. I settled on a 40ft strip pauwlonia wood strip planked trimaran. With a plank thickness of 2 cm and fiberglass/epoxy inside and out and extra fiberglass below the waterline It works out remarkably light. In my first estimations the boat shell will weigh around 1600 or 1700 kg without fittings and mast. 

This enables a small sail plan, smaller outboard, smaller rudder and dagger board etc. The smaller sail plan will eliminate the need for winches and massive blocks. To join the three hulls I designed a glass fiber leaf spring system. Basically a very large version of the new suspension system for mountain bikes.

Lauf Carbonara Fat Bike Suspension Fork - Glory Cycles

 

This connection is light weight because it doesn't rely on rigidity. It also puts less stress on the hull. Another plus is that it should even out the ride in hull-length frequency cross waves. Because each ama bow and stern can move up or down about 25cm.

But now I am stuck on what to do with the rig. I cannot afford a regular mast. I need something I can make or repurpose myself on the cheap. My first thought was lamp posts, but locally (Thailand) I have only been able to find thick walled steel light poles weighing 235KG for 12 meters. If I keel step I have 10m left so I would need a two mast arrangement to get enough sail area. Almost 500 kg of mast on such a light boat seems absurd. I have looked into wood, diy glass fiber, crab claw sails with surf masts.... None of it seems right.

While studying all existing and forgotten sail plans I stumbled on the sprit sail. I even forgot about the Optimists! The longest light weight spars I can get are only 6 meter. What if I make optimist style sprit sails out of 6m alu tubes? Each sail can be around 16M2. If I make the boat quadplane rigged, so 4 masts, 2 on each ama, I will still have a sail area of 64m2 which should be plenty for a light weight trimaran. The positives are that it will be insanely cheap, easy to handle and very safe (try capsizing that!) Especially for cruising it has a lot of redundancy. Loosing a mast wouldn't be a biggy, hell you could even carry a few spares!

BUT....Would it sail? I would guess in strong winds it would go as a locomotive and only in extreme conditions would you reduce sail by removing the sprits. Removing the sprit and tying down the sail almost halves the size. It becomes a tiny bermuda sail. I also read that sprit sails point very well and outperform bermuda sails on a reach. But in lighter air, how much would I suffer? With such absurdly low sails and lower wind due to wind gradient how much wind would I need to get going?

The boat doesn't need to be fast or sexy.....it should just sail from point A to point B safely and at least as fast as your average monohull.

Haha!! This boats going to blow to bits in the first bit of breeze. Not sure how you going to get rig tension with suspension in the Ama's just flopping around. Save your money and buy a better boat that is already built.

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Light displacement is fine, but have you worked out the weight of all the stuff you need to cruise and live aboard?  Food, water, fuel, spares, dinghy, clothes, tools, ground tackle, etc.  nothing slower than a formerly light displacement boat. 

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6 hours ago, Liquid said:

Wasn't the Tin Can recently converted to cruising and up for sale and probably way under budget? 

Vann did it his own way, and he had a glorious sail out the gate and down the coast. At least until somewhere around Davenport...

alu-trimaran-13-jpg.162079

What it looked like:

http://www.pressure-drop.us/forums/content.php?1066-Tin-Can-Recycled

and how it ended:

 

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10 hours ago, LongJohn said:

I thought you guys were anarchists? But in stead all I hear is you should do what everybody else does. Play it safe....be normal, stay on the beaten path. I think this forum should be re-named to Sailing Conformity  :-)

Don't give up too soon - there is more than one expert boat builder, and even a few naval architects inhabiting these forums. I for one tend to listen gratefully when they speak..

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20 minutes ago, ryley said:

What's your budget like? My understanding is that Paulownia is very expensive. I found one source of 6 1.25x6x96" planks for around $300. That's a lot of money, maybe it's cheaper in Thailand but given that it's a premium wood in Japan I suspect it's expensive there, too. I like the idea of you building something easily driven, but I don't think your suspension idea is going to work. I think you'll find all that flexing will cause more problems than it will solve, including not providing a good base for your shrouds. Eric Sponberg used to have plans for building a wood and fiberglass free standing masts for the do it yourselfer which would get rid of the shroud requirement:

wood-epoxy-wingmast

Light boats in heavy seas need to be well designed and well driven or you're going to find yourself in danger, another reason to not use a suspension system for your boat.

That said, I think you are providing your own confirmation bias when you say "Plus I would not feel safe on a very old boat. And in use it is probably less cheap....repairs will add up quickly."

That is entirely dependent on the "old boat" you choose. I had a 1980 Freedom 40 CK that cost $65k and with the exception of the sails, it was pretty inexpensive to run and to maintain. After I sold it, the new owner eventually sailed it across the Atlantic to England. You can disparage the lack of "anarchy" here all you want, but the people who have commented so far have watched a number of well-meaning projects like the Tin Can and the Flyin' Hawaiian and others come to doom and unmitigated failure. Dream all you want but history says you will grow old and broke trying to finish a project like this. Go ahead, go out and prove us all wrong, but at the end of it, please be honest on how much it really ended up costing.

Thanks for not running with the playground bullies here. I don't frequent internet forums but the level of toxicity here is stunning. 

Most Pauwlonia wood comes from China. Low grade and shorter pieces go for 300-400 USD/m3. Higher grade and longer pieces >240cm for around 600USD/m3. Doesn't seen very expensive to me. Maybe the market for it is just so small that if you don't import it yourself it'll cost you. And for the price in Japan, they probably only use the highest grade from a specific species...... I have been to Japan and everything is expensive there! 

Besides the discussion whether or not you would want flexibility in a multihull I think practically it is possible. In the automotive industry they are slowly moving from steel to composite leaf springs. Mercedes Benz Sprinter vans and Corvettes have composite leaf springs. They are stronger, provide better damping, are 60% lighter and don't suffer from corrosion and loss off function over time like metal leaf springs. I have even seen them on large trucks. I doubt if properly sized they cannot deal with marine loads. But I am open to arguments to the contrary.

Your point regarding a light boat in heavy seas has been on my mind also. On racers they try to shave off every gram possible but when cruising and hitting heavy weather how light do you want your boat to be? This is one point where my lack of experience in sailing bigger boats bothers me. If you have 2 similar boats, equally sturdy but one heavier than the other, which one would be preferable in a storm?

 

 

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29 minutes ago, CruiserJim said:

Light displacement is fine, but have you worked out the weight of all the stuff you need to cruise and live aboard?  Food, water, fuel, spares, dinghy, clothes, tools, ground tackle, etc.  nothing slower than a formerly light displacement boat. 

Yes I have included water tanks and battery bank in the weight calculation and yes they are located towards the center of the boat. I also included outboards, fuel, 2 anchors, composting toilet, dinghy, radar, wind vane, windlass, oven, fridge, mattress provisions and passengers.....and 200kg miscellaneous extras.

And no, there is no washing machine, aircon flat screen tv or marble counter top :-)

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7 hours ago, Liquid said:

Cheap - Light - Durable

Anarchy or not... You can only pick 2!

 

Wasn't the Tin Can recently converted to cruising and up for sale and probably way under budget? 

2 cm thick wood on a multi seems a tad overkill....

Why not just launch a giant kite, no rig needed!!

 

My favorite is the multiple rigs on amas that flail about! How fast would it shake itself apart?

 

 

Anarchy or not... You can only pick 2!   Why? Street wisdom??

It often works out that way but it is not a law of nature.

Regarding the hull thickness: Pauwlonia is very light, somewhere between balsa and the lightest pine. You cannot use it as if it is marine plywood. The advantages are that the distance between the glass skins on the inside and outside is larger which increases strength allowing for less glass. Because of this the hull also has no stringers and only bulkheads at hull connection points. Additional advantages are very good insulation for temperature and sound and a lot of buoyancy.

There was an arctic explorer yacht with a very thick cold molded hull. I imaging a tiny heater would keep it nice and warm inside. I remember as a child I had wooden shoes in winter. You would freeze to death before you got cold feet :-)

 

 

 

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18 minutes ago, LongJohn said:

This is one point where my lack of experience in sailing bigger boats bothers me. If you have 2 similar boats, equally sturdy but one heavier than the other, which one would be preferable in a storm?

 

I'm not a trimaran sailor, I'm a monohull sailor. If I were *racing* around the world, clearly I want the lighter design, but Imoca 60 sailors sail with noise cancelling headphones and custom-molded seats to withstand the noise and the slamming. I like the extra mass of my Freedom 45 offshore - it's stable and feels solid.

On a trimaran, I think you *have* to be looking at less mass in order to keep it worth doing a trimaran in the first place. 

I still don't get the desire for a "suspension" with a trimaran. My intuition tells me that by doing that you're taking drive and turning it into wasted energy. a boat is at its fastest when it is steady and not pitching - you are purposely inducing pitching into the equation with the suspension and that doesn't seem fast to me. Not to mention that one of the inherent advantages of a multihull is to widen the stance of the vessel, increase righting moment, and allow you to really power up the rig. A flexible system on the amas to me seems like you're losing that righting moment. I think you'd find the boat's performance unpredictable at best. Leaf springs work great on land, but it seems less useful at sea.

THE THREE SECTIONS of the Connector were loosely hinged together to enable the ship to ride comfortably through heavy seas 

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54 minutes ago, ryley said:

I'm not a trimaran sailor, I'm a monohull sailor. If I were *racing* around the world, clearly I want the lighter design, but Imoca 60 sailors sail with noise cancelling headphones and custom-molded seats to withstand the noise and the slamming. I like the extra mass of my Freedom 45 offshore - it's stable and feels solid.

On a trimaran, I think you *have* to be looking at less mass in order to keep it worth doing a trimaran in the first place. 

I still don't get the desire for a "suspension" with a trimaran. My intuition tells me that by doing that you're taking drive and turning it into wasted energy. a boat is at its fastest when it is steady and not pitching - you are purposely inducing pitching into the equation with the suspension and that doesn't seem fast to me. Not to mention that one of the inherent advantages of a multihull is to widen the stance of the vessel, increase righting moment, and allow you to really power up the rig. A flexible system on the amas to me seems like you're losing that righting moment. I think you'd find the boat's performance unpredictable at best. Leaf springs work great on land, but it seems less useful at sea.

THE THREE SECTIONS of the Connector were loosely hinged together to enable the ship to ride comfortably through heavy seas 

This suspension idea obviously makes rigging going from one hull to another impossible so unstayed would be the way to go. Regarding pitching: with or without a suspension the boat has to get over waves. Wouldn't some degree of individual hull movement be beneficial? Barring very small waves you have to go over them, not through them. 

Here is a thought experiment. imagine connecting one of my hulls on a long arm to an oil tanker. If the connection is flexible it will see the waves for what they are. If the connection is infinitely rigid it would be trashed around, lifted, smashed on the surface, pushed totally under water. To a lesser extent, wouldn't the same apply to two equal hulls? Wouldn't a hull finding its own balance in the water be more efficient that having to "fight" with it's neighbor's forces?

How this interacts with the rig is a different matter and here i am not sure if it is desirable or not. But there wont be much lateral flex, the hull can only move vertically.

I know flexibility has a bad name in boating but these guys have crossed oceans for thousands of years with nothing but flexibility:

Living in Tune with the Ocean – Vaka Taumako Project Strengthens Solomon  Islands Traditions

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Total beginner thinks they can design a boat. And build a boat. And they fail. You have several unique ideas. No other boats use this idea but you are convinced they are the holy grail. You ignore advice both cruel and sensible. The reason we react with strong adverse suggestions is that we have seen it all before.

Serious question: Why do you think you have the skills to design a boat? Have you any engineering background, boat design, or you've just read a bunch of books.

 

 

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1 hour ago, Zonker said:

Total beginner thinks they can design a boat. And build a boat. And they fail. You have several unique ideas. No other boats use this idea but you are convinced they are the holy grail. You ignore advice both cruel and sensible. The reason we react with strong adverse suggestions is that we have seen it all before.

Serious question: Why do you think you have the skills to design a boat? Have you any engineering background, boat design, or you've just read a bunch of books.

 

 

There are many assumptions here. And contradictions.

The reason we react with strong adverse suggestions is that we have seen it all before <------>You have several unique ideas ?!

No other boats use this idea but you are convinced they are the holy grail. ---> If I was so convinced why would I be here to hear other people's opinions? I think my ideas are good but am very open to being convinced they are very bad. I am the last person wanting to spend a year building something based on very bad assumptions. 

Another poster equated designing a sailboat to designing a plane or nuclear power plant. They sailed oceans for centuries before we had cars, planes, and power plants, aluminium, composites, navigation electronics..... so I think those kind of warnings are BS. Not that I think it is an easy thing. Wave and wind forces are considerable and there are many safety factors to take into account. I have no experience in boat building. I studied architecture and have good woodworking skills. I have built houses, furniture, commercial pizza ovens, bicycles. And yes, I have read a lot about boat design and building. 

And I am working on building a 1:10 model with correct weight distribution to test the balance of the hulls, rig, daggerboards and rudder on a lake. The wood for version one is being laser cut right now. I try to put some method in the madness :-)

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No, designing a sailboat is not like a plane or a nuclear power plant. But designing a SUCCESSFUL light weight trimaran is not simple. If you don't know what you are doing then copying other successful designs has a higher chance of success than going it yourself without any training. You have a very high chance of making a project ending mistake due to ignorance. It's not because you didn't calculate something, it's because you didn't know you had to consider a particular load.

0) You are wrong that this will save you any money. You are in a part of the world where many cruisers end their cruise. ESPECIALLY due to Covid. While the boat, engine, sails, rigging will be used, that doesn't mean they will be worn out. Many cruisers spend $$ buying new sails and equipment for their boat before setting out. Rigging, no, not so much. Older fiberglass boats are not "worn out" or less safe. That is a misconception on your part. Many people sail around the world every year in 40 year old boats.

Keep an eye on Yachtworld for Thailand and Malaysia. Lots in Langkawi  https://www.yachtworld.com/boats-for-sale/type-sail/region-asia/country-malaysia/sort-price:asc/?length=38-45

1) Your leaf spring idea is bad. 99% of successful trimarans do not use it. Copy successful designs if you are not an engineer or experienced designer.

2) Your multi mini lug rig design is bad. Just find some 6061 T6 tubing, even if you have to import it.  A conventional mast and rigging is well understood and you can do some sort of design that will not fail. 

3) You get the weight balance right with a spreadsheet of all the weights (boat + gear) and then compare the c.g. of this with the center of buoyancy of the hull. A 4' long hull makes a nice childrens toy but unless you are making teeny tiny scale weight gear it's not going to tell you anything.

4) The beams and connections of them to the main hull and amas is likely to give you the most difficulty. Study successful low-tech trimaran designs (Searunner, Horstman) and maybe copy them. 

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3 hours ago, LongJohn said:

 I don't frequent internet forums but the level of toxicity here is stunning. 

You aint seen nothin' yet, cupcake. I smoked some of that local shit when I was in your neck of the woods. Clearly doing it everyday is not a good idea.

 

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4 minutes ago, Zonker said:

No, designing a sailboat is not like a plane or a nuclear power plant. But designing a SUCCESSFUL light weight trimaran is not simple. If you don't know what you are doing then copying other successful designs has a higher chance of success than going it yourself without any training. You have a very high chance of making a project ending mistake due to ignorance. It's not because you didn't calculate something, it's because you didn't know you had to consider a particular load.

0) You are wrong that this will save you any money. You are in a part of the world where many cruisers end their cruise. ESPECIALLY due to Covid. While the boat, engine, sails, rigging will be used, that doesn't mean they will be worn out. Many cruisers spend $$ buying new sails and equipment for their boat before setting out. Rigging, no, not so much. Older fiberglass boats are not "worn out" or less safe. That is a misconception on your part. Many people sail around the world every year in 40 year old boats.

Keep an eye on Yachtworld for Thailand and Malaysia. Lots in Langkawi  https://www.yachtworld.com/boats-for-sale/type-sail/region-asia/country-malaysia/sort-price:asc/?length=38-45

1) Your leaf spring idea is bad. 99% of successful trimarans do not use it. Copy successful designs if you are not an engineer or experienced designer.

2) Your multi mini lug rig design is bad. Just find some 6061 T6 tubing, even if you have to import it.  A conventional mast and rigging is well understood and you can do some sort of design that will not fail. 

3) You get the weight balance right with a spreadsheet of all the weights (boat + gear) and then compare the c.g. of this with the center of buoyancy of the hull. A 4' long hull makes a nice childrens toy but unless you are making teeny tiny scale weight gear it's not going to tell you anything.

4) The beams and connections of them to the main hull and amas is likely to give you the most difficulty. Study successful low-tech trimaran designs (Searunner, Horstman) and maybe copy them. 

1) Your leaf spring idea is bad. 99% of successful trimarans do not use it. Copy successful designs if you are not an engineer or experienced designer.

The fact it is not common is not a good argument. I am interested to know why.

2) Your multi mini lug rig design is bad. Just find some 6061 T6 tubing, even if you have to import it.  A conventional mast and rigging is well understood and you can do some sort of design that will not fail. 

That is possibly true. The rig is what I struggle with most. What kind of rig and how to make it is still "up in the air"

3) You get the weight balance right with a spreadsheet of all the weights (boat + gear) and then compare the c.g. of this with the center of buoyancy of the hull. A 4' long hull makes a nice childrens toy but unless you are making teeny tiny scale weight gear it's not going to tell you anything. 

1.2m is a hell of a kids toy. Not sure if I agree here that it will not tell me anything.

4) The beams and connections of them to the main hull and amas is likely to give you the most difficulty. Study successful low-tech trimaran designs (Searunner, Horstman) and maybe copy them. 

Imagine the opposite, replacing a truck suspension with something light but rigid. That would would requite a lot of engineering and cutting edge materials to pull off.

I have looked at used boats and know that some very well built GRP hulls can last almost forever. But most all other parts age. For a "turn key boat" my budget seems very low, for a turn key multihull it is not even remotely sufficient. 

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42 minutes ago, LongJohn said:

There are many assumptions here. And contradictions.

The reason we react with strong adverse suggestions is that we have seen it all before <------>You have several unique ideas ?!

No other boats use this idea but you are convinced they are the holy grail. ---> If I was so convinced why would I be here to hear other people's opinions? I think my ideas are good but am very open to being convinced they are very bad. I am the last person wanting to spend a year building something based on very bad assumptions. 

Another poster equated designing a sailboat to designing a plane or nuclear power plant. They sailed oceans for centuries before we had cars, planes, and power plants, aluminium, composites, navigation electronics..... so I think those kind of warnings are BS. Not that I think it is an easy thing. Wave and wind forces are considerable and there are many safety factors to take into account. I have no experience in boat building. I studied architecture and have good woodworking skills. I have built houses, furniture, commercial pizza ovens, bicycles. And yes, I have read a lot about boat design and building. 

And I am working on building a 1:10 model with correct weight distribution to test the balance of the hulls, rig, daggerboards and rudder on a lake. The wood for version one is being laser cut right now. I try to put some method in the madness :-)

Sounds like you are following in the footsteps of another famous wacky sailor who built his own tri full of new ideas. I am not sure how that ended...

 

The Walter Mitty sailor who paid the ultimate price | Daily Mail Online

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2 minutes ago, LB 15 said:

Sounds like you are following in the footsteps of another famous wacky sailor who built his own tri full of new ideas. I am not sure how that ended...

 

The Walter Mitty sailor who paid the ultimate price | Daily Mail Online

Looks like he struggled with the rig as well

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Over the years SA has been visited by many outliers asking the design whys,  ouliers that get uppity when they get told well actually you should not approach the problem this way because collectively there is a lot of very experienced sailors on these forums.

They are not there wishing to pop your balloon rather to save you the learning of the lessons the hard way.

Marinas the world over usually have at least one maybe several monuments to the folly of an iconoclast home builder/dreamer with a better idea.

Free thinkers obsessed by breaking the rules, "there must be a easier simpler way" that instead end up breaking the laws......... of physics and engineering, hydrodynamics and aerodynamics to name a few.

Often constrained by budget,  little on the water experience and a green enough to be dangerous mindset,  the occasional one with a budget as well,  who insist on designing the boat, and everything that bolts to it themselves.

 I have to ask why?  So  I can say I did it my way?

I just don't get people that have a limited budget to get out on the sea and yet they become consumed by design, the obstacles and overcoming them.

Do you really have to indulge in the exercise of reinventing the wheel...... again?

Ever wonder why yachts look so similar, its usually due to form following function. The function proved by the worlds most unforgiving testing ground, its oceans.

The design a solution to cope with the numerous dynamic and constantly changing loads and their interactions the small bonus is when its asthetic as well

If you visit the great walls of half hull models that grace the New York Yacht Club, Seawanhaka to name just two,  you are quickly struck by the fact that just about everything design wise has already been tried, indeed some have even been revisited now that we have the advantage of some lighter stronger materials.

With limited experience I would suggest you buy the cheapest boat you can put up with,  do it up a little if you have to and sail it for a year or more.

If after that exercise you still feel driven to design and build your own,  you can sell a boat it may actually have some value.

There are specialists in every aspect of the marine world, indeed there are numerous niche specialties, if you feel so motivated approach someone and ask why,  they will often save you a lot of time and money and save you from designing and building something so individual you end up owning an orphan, an expensive one that cannot be given away,  there is at least one in every marina I've been to, you can just tell...... the money and the enthusiasm has run out,  they look like worthless pieces of shit because usually they are.

Life is short,  go sailing.

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12 minutes ago, Navig8tor said:

Over the years SA has been visited by many outliers asking the design whys,  ouliers that get uppity when they get told well actually you should not approach the problem this way because collectively there is a lot of very experienced sailors on these forums.

They are not there wishing to pop your balloon rather to save you the learning of the lessons the hard way.

Marinas the world over usually have at least one maybe several monuments to the folly of an iconoclast home builder/dreamer with a better idea.

Free thinkers obsessed by breaking the rules, "there must be a easier simpler way" that instead end up breaking the laws......... of physics and engineering, hydrodynamics and aerodynamics to name a few.

Often constrained by budget,  little on the water experience and a green enough to be dangerous mindset,  the occasional one with a budget as well,  who insist on designing the boat, and everything that bolts to it themselves.

 I have to ask why?  So  I can say I did it my way?

I just don't get people that have a limited budget to get out on the sea and yet they become consumed by design, the obstacles and overcoming them.

Do you really have to indulge in the exercise of reinventing the wheel...... again?

Ever wonder why yachts look so similar, its usually due to form following function. The function proved by the worlds most unforgiving testing ground, its oceans.

The design a solution to cope with the numerous dynamic and constantly changing loads and their interactions the small bonus is when its asthetic as well

If you visit the great walls of half hull models that grace the New York Yacht Club, Seawanhaka to name just two,  you are quickly struck by the fact that just about everything design wise has already been tried, indeed some have even been revisited now that we have the advantage of some lighter stronger materials.

With limited experience I would suggest you buy the cheapest boat you can put up with,  do it up a little if you have to and sail it for a year or more.

If after that exercise you still feel driven to design and build your own,  you can sell a boat it may actually have some value.

There are specialists in every aspect of the marine world, indeed there are numerous niche specialties, if you feel so motivated approach someone and ask why,  they will often save you a lot of time and money and save you from designing and building something so individual you end up owning an orphan, an expensive one that cannot be given away,  there is at least one in every marina I've been to, you can just tell...... the money and the enthusiasm has run out,  they look like worthless pieces of shit because usually they are.

Life is short,  go sailing.

The why is a complicated question. I like the challenge. I always tried to push limits where others played it safe. As a teenager I would ride my bicycle thousands of miles through Europe or hitchhike all over when my peers weren't even allowed to venture out alone. When I bought my first house I didn't have enough to buy something decent so I bought a run down place in a great location. Spent a year turning it into a beautiful place and sold it for 3x the purchasing price a few years later. I admire people who try new things. I have respect for people like Thor Heyerdal, James Wharram..... Sure failure is a possibility and there are risks.

But I don't like to be double masked, fully insured, ISO compliant.... When I see all the great yacht experiments that went on in the 70's I feel current times are boring in comparison. As a society we are ruled by the "experts" in every field. There is no more creativity, adventure. The biggest adventure people have nowadays is watching some douchebag trillionaire firing rockets into the sky. And now with the CV1984 shit even walking down the street is hazardous to you and society. Different strokes for different folks. Imagine the difference in feeling between going to the dealer, buying the latest yacht and crossing an ocean or designing, building and sailing it over the same ocean on a tight budget. The latter would feel more like discovering a new continent or having your personal Neil Armstrong moment. Sure it can fail, but that wouldn't devastate me......tried, failed, lesson learned. And if I drown in the process? So be it. 

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Ok, all that is fine, but why come here?  We have some extremely talented designers here—collectively, they’ve drawn, built, and sailed hundreds of boats ranging from dinghies to commercial ships.  We have some real iconoclasts, too—check out the proa page for massive ego clashes and radically different viewpoints. We’ve got people who have sailed around the world on everything from used 28 foot sloops to megayachts.  And, of course, we have a large body of folks who just spend a lot of time on the water.  You want our opinions, we got opinions.  But you seem to NOT want anyone’s opinions.  So, build your boat with your bicycle fork bendy akas and your lateen rigs made out of window frame aluminum.  In all seriousness, I wish you the very best of luck. Maybe you’ll change the world!  But don’t get all shirty when people here don’t accept your unproven ideas that fly in the face of their life experiences.  You asked!

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28 minutes ago, The great unwashed said:

Ok, all that is fine, but why come here?  We have some extremely talented designers here—collectively, they’ve drawn, built, and sailed hundreds of boats ranging from dinghies to commercial ships.  We have some real iconoclasts, too—check out the proa page for massive ego clashes and radically different viewpoints. We’ve got people who have sailed around the world on everything from used 28 foot sloops to megayachts.  And, of course, we have a large body of folks who just spend a lot of time on the water.  You want our opinions, we got opinions.  But you seem to NOT want anyone’s opinions.  So, build your boat with your bicycle fork bendy akas and your lateen rigs made out of window frame aluminum.  In all seriousness, I wish you the very best of luck. Maybe you’ll change the world!  But don’t get all shirty when people here don’t accept your unproven ideas that fly in the face of their life experiences.  You asked!

Who is getting shirty? I come here with legitimate concerns, knowing I don't know enough, trying to learn something an all I get is people asking if they can see my whore girlfriend's tits. You think that is normal civilized behavior? I didn't come here claiming I know everything. I try to explain why I have a certain idea and so far the only reaction is "oh he so dumb", "what an idiot". Can somebody please show me with facts what an idiot I am instead of just dismissing everything as moronic.

I already scrapped my 4 sails idea. That was a dumb idea. Not realized because of this forum's collective effort to save me from myself but rather reading some more on the science behind sail lift and drag. 

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17 hours ago, notallthere said:

Why not sleeve the 6m alum tubes you have available to make a 12 or 18m long mast(s)?

 

Just found some beautiful 12m tapered 6061 T6 Alu flag poles with 140mm base and 5.1 mm wall thickness for the bottom section. Might be usable in a biplane configuration. Maybe with junk rig soft wing sails?

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3 hours ago, LongJohn said:

Who is getting shirty? I come here with legitimate concerns, knowing I don't know enough, trying to learn something an all I get is people asking if they can see my whore girlfriend's tits. You think that is normal civilized behavior? I didn't come here claiming I know everything. I try to explain why I have a certain idea and so far the only reaction is "oh he so dumb", "what an idiot". Can somebody please show me with facts what an idiot I am instead of just dismissing everything as moronic.

I already scrapped my 4 sails idea. That was a dumb idea. Not realized because of this forum's collective effort to save me from myself but rather reading some more on the science behind sail lift and drag. 

WHY ARE YOU HERE

You have no respect for our traditions, including the greeting we all got, you have no respect for our knowledge, and you have no respect for our experience. You are likely just a troll, but on the off chance you somehow don't have the money to buy and maintain a used boat but do have the time and money to build a boat from your own never-been-done-before plans, why not just do it? Why come here?

I suggest you quit going off about your amazing ability to do your own thing and sail a boat through a storm offshore. Then you can talk to us. Or maybe just fuck off and make your flexible boat and see what happens.

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I think the over/under length for "can home brew something usable, cheaper" v. "buy something existing" is somewhere around the length of a sheet of plywood.

Buy some slow boat today for $30k and you'll have a several year head start and budget to arrive before your project boat would.

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5 minutes ago, LongJohn said:

WHY ARE YOU HERE to you too. 

Being a keyboard asshole is easy. In real life someone will break your nose.

You are far from the first internet tough guy on SA and far from the first "I have a better idea you all are idiots" guy on SA either :rolleyes:

Whose sock are you anyway?

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9 minutes ago, Dex Sawash said:

I think the over/under length for "can home brew something usable, cheaper" v. "buy something existing" is somewhere around the length of a sheet of plywood.

Buy some slow boat today for $30k and you'll have a several year head start and budget to arrive before your project boat would.

Besides for that, one could probably sell the $30K boat for $30K in the future and the Flyin' Hawaiian II will be worth the scrap value of the metal and engine even brand new.

The likely end result of this project:

https://www.mercurynews.com/2015/02/03/five-rescued-as-marins-notorious-flyin-hawaiian-catamaran-sinks-at-sea/

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11 hours ago, LongJohn said:

Barring very small waves you have to go over them, not through them. 

and yet most fast, non-foiling trimarans are designed to go through them with wave-piercing shapes.

I think the problem with linkages to the amas is that if they aren't some form of active suspension, you're just going to get wave amplification and out of phase on each side of the boat, and you'll end up just hobby-horsing the amas at low speed while the main hull gets hit with all the power of the waves you were trying to mitigate. I could be wrong. it wouldn't be the first time. I get your 'build it yourself' attitude, I wanted to build a pedal-powered plane when I was 10 and thought of ways to convert my columbia bicycle to do that. Of course I had no idea how incredibly hard that engineering feat really was, as proven out by the Gossamer Condor which was itself an innovative design. I've owned two boats that came from Garry Hoyt's and Eric Sponberg's unconventional minds, and so I'm not afraid of a little out of the box thinking. But if I came here with an innovative idea and Zonker told me I was going down a path of doom and unmitigated failure, I'd probably listen to him.

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21 hours ago, Huggy Bear Brown said:

Do what you want and just wear the biggest lifejacket you can find...........and safety glasses......and a hard hat.  What could go wrong and yes, life might be shorter than you ever imagined

Just ditch the steel toe boots..  or do not do up the laces.. hard to swim... ;)

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16 hours ago, basketcase said:

These guys are right up your alley. They have some interesting ideas in naval architecture that you could try to copy. https://nutshellcatamarans.com/

Now, fuck off newbie and show us your wife's or girlfriend's tits 

Ho-Lee-Fucking-Shite, they finally invented toilet paper holders for fenders! I guess if  you are not going to put them away properly you might as well finish the disguise...

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There people do a yearly show right on the island. If you just HAVE to make your own boat, I can think of worse places to get plans. Their boats actually work :D

https://www.clcboats.com/shop/boats/wooden-sailboat-kits/proa/madness-31-foot-pacific-proa.html

 

Another one that works:

https://www.searunner.com/index.php/designs/searunner-trimarans

These things pop up for sale every now and again and I think you can still get the plans.

 

 

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23 hours ago, LongJohn said:

There are no rules in Anarchy bro.

That is actually not true. Anarchy means there is no ruler (you can look up the etymology if you like) but that does not exclude the possibility of rules.

I could provide a few rules you should follow in designing a boat, but my guess is that it will be lost on you.

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14 hours ago, LongJohn said:

If you have 2 similar boats, equally sturdy but one heavier than the other, which one would be preferable in a storm?

The one you didn’t build

11 hours ago, LongJohn said:

 I am the last person wanting to spend a year building something based on very bad assumptions

Then you are already ahead of the game. Your assumptions trump local knowledge and advice 

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4 hours ago, kent_island_sailor said:

WHY ARE YOU HERE

You have no respect for our traditions, including the greeting we all got, you have no respect for our knowledge, and you have no respect for our experience. You are likely just a troll, but on the off chance you somehow don't have the money to buy and maintain a used boat but do have the time and money to build a boat from your own never-been-done-before plans, why not just do it? Why come here?

I suggest you quit going off about your amazing ability to do your own thing and sail a boat through a storm offshore. Then you can talk to us. Or maybe just fuck off and make your flexible boat and see what happens.

well said

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