tumbleweed314

Construction of a Pogo 50

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I bet a lot of people here remember the "Construction of a Pogo 12.50" thread by @shaggybaxter a few years back.  Well, the title is probably pretty self explanatory. The build of my Pogo 50 started today.  Happy to post progress picks and talk about the design decisions I made/still need to make if anyone is interested. 

I spent a couple years researching which boat I wanted to get. The design spec is pretty simple-- I want to push as far as possible on the performance end of the performance cruiser spectrum for a 50 foot boat.  Finding the right boat was not simple.  I narrowed down to the following boats before making the choice of the Pogo.  There's a million things that make a boat purchase decision, but the most important metric for me was power to weight ratio.  I wanted a cruising boat that approached the P/W ratio of a TP 52.  Yikes!  The summary is below, but I attached the excel spreadsheet in case anyone else things along these lines.  

 

Boat Upwing Sail:displacement ratio (m2/kg)
Pogo 50                    1.81
Pogo 50- 2M taller mast + running backstays                    1.94
TP52                    2.35
Clubswan 50                    1.86
J/121                    1.73
FC53                    1.78
j/88                    2.11
J/133                    1.43
xP 44                    1.24
xp50(deep)                    1.28
xp55 deep                    1.04
Jeanneau 49 ds (my old boat)

                   0.96

 

 

 

boat_comparison.xlsx

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Congrats on your new boat. I'm looking forward to following it's construction.

Why did you focus on Sail Area : Displacement in the absence of Displacement : Length?

 

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Did you make a reasonable allowance for the weight of cruising gear? Extra weight is much more noticeable on very light boats. Both numerically in the SA/D and in sailing performance.Like proper anchors and rode (think windage aloft), for one, and the windlass needed to handle it.  Speaking of anchors...I hear a Pogo's rolling at anchor is something to respect. Choose your anchorages carefully.

However, great choice. My points are not deal-killers in any way. Well worth the issues. It will be super fun. Not sure what you can do except be very minimal with the gear.

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I think I speak for a lot of us who will never go through this process when I say please share every part of the process you’ve already been through and have yet to do. Congrats on your new boat. Look forward to seeing it. The 50 is a hell of a boat.

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@apophenia  I've been very happy with the 50 ft Jenneau, in terms of a balance between waterline, availability at harbors, and maintainability, so in my mind that number was a constant. 

35 minutes ago, El Boracho said:

Did you make a reasonable allowance for the weight of cruising gear? Extra weight is much more noticeable on very light boats. Both numerically in the SA/D and in sailing performance.Like proper anchors and rode (think windage aloft), for one, and the windlass needed to handle it.  Speaking of anchors...I hear a Pogo's rolling at anchor is something to respect. Choose your anchorages carefully.

However, great choice. My points are not deal-killers in any way. Well worth the issues. It will be super fun. Not sure what you can do except be very minimal with the gear.

I agree. I think of Cruising, like I think of ultralight backpacking. So, the design follows that:  Only 1 head. Electric induction range, rather than a propane system. No genset. Lithium Batteries. There's 3 cabins, but the forward one is pipe berths, and the aft 2 are more comfort oriented.  One of the things I like about the Pogo interior is that there is very minimal trim/headliner, cutting down on weight.  I toyed with no windlass, but decided to keep it, and just go with underpowered.   Interestingly the single head can cause issues while heeling on passage, so it will be oriented fore & aft.  

The only creature comfort that I decided to keep was a very small A/C for just the main salon, with no ducting.  In theory it's small enough to run off an inverter on the batteries, along with a hydrogenerator while on passage.  In practice... I guess I'll see! 

 

23 minutes ago, Alaris said:

I think I speak for a lot of us who will never go through this process when I say please share every part of the process you’ve already been through and have yet to do. Congrats on your new boat. Look forward to seeing it. The 50 is a hell of a boat.

Well, in that case, here's the first photo. This is the molds in place in the workshop earlier today. They've been waxed, and the keel cutout has been boxed in.  It looks like a 50 foot surfboard! 

waxed molds.jpg

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34 minutes ago, Alaris said:

I think I speak for a lot of us who will never go through this process when I say please share every part of the process you’ve already been through and have yet to do. Congrats on your new boat. Look forward to seeing it. The 50 is a hell of a boat.

So, actually talking about what I've been through already. 

There's the research, and talking to a bunch of different owners about their experiences with various builders.  Plus, and this might not be obvious, but the most important thing I did in terms of understanding background was upgrading my Jeanneau 49DS.  It's a tub of a cruising boat, but we got 2nd in section and 9th overall in the Mac last year after 5 steady years of upgrades.  Making all of those upgrades helped me form opinions about how to make a boat go fast, and also how to do it with minimal rating penalties in ORR.  

They put me in touch with another owner, and I flew to Maine to sail on his boat for a day. Then it became less about spreadsheets and more about just loving the boat.

All of this gave me the confidence that I needed to ask them to modify the sail plan.  Their first response was polite, but the essence of it was... uh... you're not exactly a marine architect.  But, they listened.  Once I told them that I think it's possible if we add running backstays (there's no fixed backstay on the Pogo, just swept spreaders), they realized that I was very serious about the performance mod.  So, we were able to get two more meters on the mast, and maintain the same weight aloft by going with a higher modulus carbon, carbon boom,  and carbon spreaders. (for the bargain price of three times what I sold my old Catalina 28 for) 

After the rig, the other design specs are largely aren't as critical-- I'm sticking with their philosophy that the #1 jib is all or nothing on a Karver, but the inner stay can be fractionally furled. I opted for three speed winches, because there's going to be a hell of a lot of line on the spin sheets.  The only two weird things I asked for was in deck LED lights flush on the foredeck pointed up at the inside of the jib so I can see telltales while racing overnight, and a removable bench that can be fitted into the companionway as a place to sit while using autopilot on non-race passages. 

 

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Congratulations on your new build! Are you planning to solely cruise or race as well? If you really want to add power in the light airs you can look at getting a J0 or MH0 for added grunt. Did you go for the lift keel or fixed keel?

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3 hours ago, JL92S said:

Congratulations on your new build! Are you planning to solely cruise or race as well? If you really want to add power in the light airs you can look at getting a J0 or MH0 for added grunt. Did you go for the lift keel or fixed keel?

Mostly offshore racing. I'm sailing it back to the US next summer from France. So, that will be cruising, other than the ARC.  

MH0-- So, I'll be getting Masthead Code 65%,also known as a Large roach headsail(LRH), or a tweener.  This code sail is BIG! 183 m2. 

Most code zeros have a mid girth of greater than 75% of the foot, any less than that and it can't be classified a spinnaker. But a lot of the rating rules in the last couple years are allowing for as low as 55% of mid girth on a code sail.  The penalty goes up exponentially as the mid girth goes down. So, for a 65% sail, the penalty isn't that bad.  I've used one of these for 2 years, and they can point quite high. Not as high as a jib, but there's a special feeling of having a code sail on, and seeing the apparent wind so far forward. 

Here's a video of my current one in action earlier this season. It's pretty amazing how high these things point. (go to 45 seconds to see the code 65): 

 

 

 

Edited by tumbleweed314
adding a link.

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17 hours ago, El Boracho said:

Did you make a reasonable allowance for the weight of cruising gear? Extra weight is much more noticeable on very light boats. Both numerically in the SA/D and in sailing performance.Like proper anchors and rode (think windage aloft), for one, and the windlass needed to handle it.  Speaking of anchors...I hear a Pogo's rolling at anchor is something to respect. Choose your anchorages carefully.

However, great choice. My points are not deal-killers in any way. Well worth the issues. It will be super fun. Not sure what you can do except be very minimal with the gear.

IME, that isn't accurate. Extra weight matters on a boat with a narrow waterplane that will "sink" fast which will alter its hull lines. On a wide boat like this, the boat will plane later and be a bit slower upwind but its seaworthiness and its behaviour won't be affected that much as you need a lot of weight to "sink" it. Also you are less likely to store crap on deck which is the surest way to slow down a boat (weight up hgh which is the worst kind of weight + windage).

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56 minutes ago, Panoramix said:

IME, that isn't accurate. Extra weight matters on a boat with a narrow waterplane that will "sink" fast which will alter its hull lines. On a wide boat like this, the boat will plane later and be a bit slower upwind but its seaworthiness and its behaviour won't be affected that much as you need a lot of weight to "sink" it. Also you are less likely to store crap on deck which is the surest way to slow down a boat (weight up hgh which is the worst kind of weight + windage).

Hmmm....then why bother with carbon fibre? ;-)

That might be true considering wetted area alone. Would take some maths. However the displacement of water is independent of hull shape. Every kilo added is another kilo of seawater that must be "pumped from the bow to the stern" to move the hull forward. Or in planing mode each extra kilo must be lifted which directly increases induced drag.

I don't think any naval architect had in mind cargo capacity when considering the advantages of the POGO hull.

The OP seems to have it under control...except for that small air conditioner idea IMHO.

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47 minutes ago, El Boracho said:

Hmmm....then why bother with carbon fibre? ;-)

That might be true considering wetted area alone. Would take some maths. However the displacement of water is independent of hull shape. Every kilo added is another kilo of seawater that must be "pumped from the bow to the stern" to move the hull forward. Or in planing mode each extra kilo must be lifted which directly increases induced drag.

I don't think any naval architect had in mind cargo capacity when considering the advantages of the POGO hull.

The OP seems to have it under control...except for that small air conditioner idea IMHO.

Carbon fibre because every gram makes the boat slower!

My point was just that overloading a wide boat isn't as bad as overloading a narrow boat that will see its floatation line rise quicker.

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19 hours ago, El Boracho said:

Did you make a reasonable allowance for the weight of cruising gear? Extra weight is much more noticeable on very light boats. Both numerically in the SA/D and in sailing performance.Like proper anchors and rode (think windage aloft), for one, and the windlass needed to handle it.  Speaking of anchors...I hear a Pogo's rolling at anchor is something to respect. Choose your anchorages carefully.

However, great choice. My points are not deal-killers in any way. Well worth the issues. It will be super fun. Not sure what you can do except be very minimal with the gear.

I’ve sailed a lot on a pogo 12.5 absolutely loaded down with crap; gear, stores, sails, miles chain, etc, and it was still a rocket ship. Damn thing planed On a white-sail close reach. Bigger denominator on the 50.  Amazing boats. 

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7 hours ago, El Boracho said:

The OP seems to have it under control...except for that small air conditioner idea IMHO.

You're probably right. The AC doesn't match the rest of the design spec.  That said, it will prove valuable in indoctrinating my 5yo daughter that the more spent time on the boat, the better, which shifts the vote at home 2-1 in my favor.   

I might actually remove it for racing season.  

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37 minutes ago, tumbleweed314 said:

You're probably right. The AC doesn't match the rest of the design spec.  That said, it will prove valuable in indoctrinating my 5yo daughter that the more spent time on the boat, the better, which shifts the vote at home 2-1 in my favor.   

I might actually remove it for racing season.  

I doubt it is worth the effort to remove it. On a boat that size a small AC is unlikely to have any meaningful effect on performance. 

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55 minutes ago, tumbleweed314 said:

You're probably right. The AC doesn't match the rest of the design spec.  That said, it will prove valuable in indoctrinating my 5yo daughter that the more spent time on the boat, the better, which shifts the vote at home 2-1 in my favor.   

I might actually remove it for racing season.  

Don’t worry about it - ppl can always knock your business as if their personal choices > yours. You opted to have one marine head. One marine head weighs more than any marine AC system you will end up having for a Pogo 50. 

Don’t let your generous thread become a place where ppl ruin your actual exp. 

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Hi tumbleweed. Thanks for starting this journey. Try and contact Shaggy Baxter, (and if possible other owners), He will be a good resource. I was lucky enough to get around the Pogo factory a few years ago. Great fun.

Make sure you get it commissioned by the manufacturer in France before bringing it back to wherever you will eventually sail. That way you can ensure systems are working, before hand over. We had a bloke try to commission his 12.5 over here, and even with a very experienced team it cost almost as much as the original boat. It was a litany of stuff ups. 
All the best. CK.

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42 minutes ago, Captain Ketamine said:

Make sure you get it commissioned by the manufacturer in France before bringing it back to wherever you will eventually sail. That way you can ensure systems are working, before hand over. We had a bloke try to commission his 12.5 over here, and even with a very experienced team it cost almost as much as the original boat. It was a litany of stuff ups. 
All the best. CK.

For sure. One of the advantages of sailing it back is that the sea trials happen before/at delivery.  

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2 hours ago, McGyver said:

Won't runners be a problem for short-handed cruising?

#1 The original spec didn't have runners, and the mast was 2 meters lower. So, with one reef in, the boat is essentially back to it's original non-reefed spec, and I can leave the runners slack. The boatyard agrees. 

#2 #1 is a moot point. Top of the sail should clear underneath the masthead runners with a reef in, so actually, I can just leave them both set if I have a reef in. 

#3 Pogo specifically stated that they ran the new spec to make sure the runningbacks aren't necessary to keep the mast up, just that they are necessary for performance and longevity of the rig.  The exception case is with the masthead spin downwind in 20+ knots. In that case, "Definitely have the runners on" they said. 

But, yes, shorthanded cruising, in light airs without a reef will be a pain in the ass. 

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1 hour ago, tumbleweed314 said:

But, yes, shorthanded cruising, in light airs without a reef will be a pain in the ass. 

In which case, bung the reef in anyway, set up both backstays and relax.  Won't make much difference to cruising performance, and you can sup your beer while tacking.

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Congrats and good luck tumbleweed! I hope you keep us updated as well as shaggy did, i think every one of us were as excited as he was when he took delivery.

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Great thread.  Sounds like it could be a fantastic project.

Thank you for keeping us informed.

Put plenty of thought into the internal layout and sail storage.

You want to be able to lay out the big headys etc flat without walking on them. Also in heavy conditions off the breeze you will want to get everything out of the bow,  you need somewhere to put it.

Galley U shaped and small so you can wedge yourself in. 

You can never have enough pipe berths!!!

Also try and avoid all roof liners, nothing worse than having a leak in a boat with a roof liner.

Can they build it out of epoxy?, quite a bit lighter.

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4 hours ago, P_Wop said:

In which case, bung the reef in anyway, set up both backstays and relax.  Won't make much difference to cruising performance, and you can sup your beer while tacking.

Definitely. I'll finish that beer and relax just after I tweak this one last thing.... 

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52 minutes ago, DiasDePlaya said:

Do you want to sail fast? Really? (Anyway the Pogo 50 is a very nice boat)

TS5 going fast

He ordered a pogo 50 that’s already under build, take the daydreaming elsewhere. 

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Very cool, posting in here to keep updated.
I have only had good experiences with Karver gear RE: the winches, although I'm not familiar with the winches specifically.

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Next week, I'm finalizing the specifications for the electrical system.  Here's the relevant facts:

1)The first five hulls had a Volvo 55hp Diesel. That model isn't available anymore, so the choice was a 50hp or 60hp w/ turbocharger. The weight/size for the two engines are almost the same. So, a 60hp diesel is on order already. This decision is made, and can't be changed. 

2)As I mentioned before, there's no genset, but there is an AC. It may be possible to run the engine->charge batteries ->use inverter ->run AC.  

Here's my question: my understanding is that alternators are typically current limited, more than they are wattage limited. Therefore, a 48V battery system can be charged by an alternator about 80% faster than a 24V system, which is about 90% faster than a 12V sytsem. (This is the big "innovation" behind the company Integral)  Given the design spec, that argues that the house batteries are at 48V.  All of the large systems can be run on 48V (solar panels, hydrogenerator, windlass, induction cooking) but the lights & B&G electronics are only specced for 12V or 24V. So, that would require a transformer and a 3rd power bus.   The other advantage of the 48V system is the smaller gauge wiring makes the need for a dedicated battery on the windlass go away. 

So, here's the debate in my mind:

Option 1) Simpler 24V house bank.

Option 2) Faster charging 48V house bank-- essentially using the main diesel as a genset. 

Not an option) 12V House bank. There's no advantage to this system, other than it's most common. Booooo. 

 

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23 minutes ago, tumbleweed314 said:

Here's my question: my understanding is that alternators are typically current limited, more than they are wattage limited.

I would want to see the engineering on that assumption. In general alternators, motors and the like are limited by watts (power) per pound. The total mass of wire and magnetic material does not vary with power. For example for 48 volts vs. 12 Volts the wire will be 4 times smaller but the number of turns (mass) will be 4 times more. The magnetic parts are identical. Ultimately they are smoke limited. 48 V is much more efficient in distribution, and creates a human safety problem.

Cutting edge people like you should try flywheel alternator tech: A propulsion engine alternator that would rival generator output. Or some other PTO solution.

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11 hours ago, tumbleweed314 said:

.......  Given the design spec, that argues that the house batteries are at 48V.  All of the large systems can be run on 48V (solar panels, hydrogenerator, windlass, induction cooking) but the lights & B&G electronics are only specced for 12V or 24V. So, that would require a transformer and a 3rd power bus.   The other advantage of the 48V system is the smaller gauge wiring makes the need for a dedicated battery on the windlass go away. 

So, here's the debate in my mind:

Option 1) Simpler 24V house bank.

Option 2) Faster charging 48V house bank-- essentially using the main diesel as a genset. 

Not an option) 12V House bank. There's no advantage to this system, other than it's most common. Booooo. 

 

Your 48V plan is good.  There are many industrial automation suppliers that offer a compact and reliable 48V to 24V (or 12V) DC/DC converter.  Just put one in close to the load to drop the voltage to each system that needs 12 or 24, lights, B&G etc...  

An example:

https://www.pulspower.com/us/products/show/product/detail/cd5242/

CD5.242 - DC/DC converter

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Congrats Tumbleweed! 

Am hoping for lots of pics, no pressure good sir :).

I got to do a walk through of a 50 under construction, the thing is fucking cavernous below, you'll be spoilt rotten. 

Anything I can do to help mate lemme know. Bottle washing, baby care...... 

Say G'day to the team, can't ask for a nicer bunch of people. 

 

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I'm skeptical that the 48V chargers will charge much faster than 24V. Also, 48V means your batteries will have twice as many series connections between the cells, which can complicate charge balancing between them and increases the odds that an out of spec cell will be a problem. Make sure you've got a top-shelf BMS for those batteries. I suspect you could get away without a dedicated thruster battery even at 24V and would still have reasonably svelte cabling.

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I'm going to backtrack on advice on marine DC stuff.  This is immensely complex, and has to be treated as a complete system, or preferably a system of systems.  Get it wrong at the outset, and you'll be stuck with an inefficient and possibly fragile electrical system for ever.

My strong suggestion is to contact Nigel Calder, who has been working on marine DC stuff and writing about it for a decade or more in Professional Boatbuilder and elsewhere.  It may cost you now, but I pretty well guarantee you'll be able to sleep at night in the future.

Ask Haji (Bruce Schwab) what he thinks.  He posts here.

 

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13 hours ago, El Boracho said:

12 Volts the wire will be 4 times smaller but the number of turns (mass) will be 4 times more. The magnetic parts are identical. Ultimately they are smoke limited. 48 V is much more efficient in distribution, and creates a human safety problem.

But more turns necessarily reduces mass, because of the geometry of the turns. So generally, it's not a linear tradeoff.  Theory aside, every time I look on an alternator website, the aggregate wattage for higher voltage alternator is always higher than low voltage alternator given a constant frame size.  

For example: https://balmar.net/products/extra-large-case-alternators/. 2x voltage equates to 1.5x current, so a 50% increase in watts. 

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1 hour ago, P_Wop said:

I'm going to backtrack on advice on marine DC stuff.  This is immensely complex, and has to be treated as a complete system, or preferably a system of systems.  Get it wrong at the outset, and you'll be stuck with an inefficient and possibly fragile electrical system for ever.

Yeah. This is true. Ultimately, I know a lot about electrical systems, but not a lot about marine electrical systems. So, at some point, I need to let the boatyard do what they are good at. 

 

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9 hours ago, tumbleweed314 said:

Yeah. This is true. Ultimately, I know a lot about electrical systems, but not a lot about marine electrical systems. So, at some point, I need to let the boatyard do what they are good at. 

 

Yep. Don’t do one off de novo stuff unless you want to spend a lot of time fixing it or making drama videos. 

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I have a window!  Woohoo! 

Also, a transom.  That's one of the parts that's not supposed to fall off, BTW. 

 

DSC_8529.jpg

DSC_8527.jpg

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