mookiesurfs

To Foil or not to Foil, that is the question

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I think we're all pretty comfortable with the concept of induced drag, and I framed my question poorly. What I intended to ask was if the induced drag penalty from generating lift while not foiling upwind was offset by reduced parasitic (form and skin) drag because the hull is riding a little higher in the water from that lift, although not foiling.

This is an probably an entirely anecdotal and intuitive answer that comes from experience, unless someone has a flow tank. That's all I was looking for, experienced and intuitive opinions.

I wanted these opinions so I could then decide if the time and effort penalty of resetting the boards was worth it. 

It's all moot if the boat blows away. How do you stay with the boat?

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47 minutes ago, mookiesurfs said:

Thanks All

That was to thank you all for the previous advice. When I reread it, it seemed like it could be taken as sarcasm for losing the boat. It's not. 

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2 hours ago, mookiesurfs said:

It's all moot if the boat blows away. How do you stay with the boat?

It's shocking to hear it happened to you. But it's also one of the "known features" of modern a class cats.

What I've heard is "don't let go of the mainsheet" - which in the heat of the moment may or may not be applicable advise.

As sailor of a different foiling cat, I might say - trick your mast top to sink, not to float, maybe with an easy way to re-seal it when you're racing. So in a racing context, there's support boats and a fleet around you, nd you don't want to waste time to a capsize. Any other time, let it sink, so you can swim to it safely.

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mookie, did you get your boat back?


If you let an A-Cat mast sink, good luck! SimonN points this amount above; the boat is impossible to right, and you can break the rig while doing so. Not advisable on this or any other cat. What is advisable is to have a rib in tow or at least another competent sailor around to get you to the boat, and to launch downwind of your sailing area when learning.

 

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2 hours ago, mookiesurfs said:

I think we're all pretty comfortable with the concept of induced drag, and I framed my question poorly. What I intended to ask was if the induced drag penalty from generating lift while not foiling upwind was offset by reduced parasitic (form and skin) drag because the hull is riding a little higher in the water from that lift, although not foiling.

This is an probably an entirely anecdotal and intuitive answer that comes from experience, unless someone has a flow tank. That's all I was looking for, experienced and intuitive opinions.

I wanted these opinions so I could then decide if the time and effort penalty of resetting the boards was worth it. 

It's all moot if the boat blows away. How do you stay with the boat?

Mookie,

In more breeze, when you are really foiling and the top guys are always foiling, which is now in 12kts (Ashby is 10-11kts) and above, generally you can leave the foils alone as SimonN mentions. You’ll get into a skim mode with a target upwind speed of 16kts, where the foils are getting a good bit of the hull out and this is quick. Tacking angles are lower-in a lull they could be 10degrees lower than in high mode, but you’re 3-4kts faster. Then from this mode you work to go foiling upwind, which if you are working it properly should be the same height or higher than the skim mode.

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30 minutes ago, samc99us said:

mookie, did you get your boat back?


If you let an A-Cat mast sink, good luck! SimonN points this amount above; the boat is impossible to right, and you can break the rig while doing so. Not advisable on this or any other cat. What is advisable is to have a rib in tow or at least another competent sailor around to get you to the boat, and to launch downwind of your sailing area when learning.

 

Oh yeah, got the boat back. The Hobie that picked me up had wings, so when they came by I just grabbed one and swung up. They gybed down to my boat, and as they went below it I rolled back off the wing. The Hobie stuff was fun. He had guest crew, and their eyes were big as dinner plates. Yep, that's catamaran racing. Then, the Hobie dropped its mast later in the race when a chainplate broke. I helped them clean up when they came in, and I'm pretty sure his guests had a memorable outing.

My boat blew right to me once I was below it. I will say this about A cats, they are the easiest boats to right and get back on.

Finished the race, although broken trap bungees are a pia.

I think I'm going with Bethwaite key hole and ball trap fittings from Murrays. Positive attachment and detachment with the original 2 ball design. Also, going to modify the trap bungee purchase. Right now the trap bungee crosses between the hulls 3 times. I think I'll add a set of blocks and have the bungee cross 5 times to give it more stretch before it breaks.

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3 hours ago, mookiesurfs said:

I think we're all pretty comfortable with the concept of induced drag, and I framed my question poorly. What I intended to ask was if the induced drag penalty from generating lift while not foiling upwind was offset by reduced parasitic (form and skin) drag because the hull is riding a little higher in the water from that lift, although not foiling.

This is an probably an entirely anecdotal and intuitive answer that comes from experience, unless someone has a flow tank. That's all I was looking for, experienced and intuitive opinions.

I wanted these opinions so I could then decide if the time and effort penalty of resetting the boards was worth it. 

It's all moot if the boat blows away. How do you stay with the boat?

Oh wow, sorry to hear that! have you been able to rescue the boat without major damage at least? 

Me as a relatively inexperienced catamaran sailor (<5 years experience) is trying to firmly grab whatever I have in my hand when realizing the capsize, sheet, trapeze, tiller extension. Could cost you the tiller extension as I have experienced (memo to myself: Run a string of dyneema trough the stick)

 However I can imagine there are situations where it is not working. So there is the advice from many experienced guys to go out with more boats ideally, but hey, this is not always feasible...haven't been there and hearing the cellphone is not doing the job let me think as well how helpful it is.

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1 hour ago, martin 'hoff said:

It's shocking to hear it happened to you. But it's also one of the "known features" of modern a class cats.

What I've heard is "don't let go of the mainsheet" - which in the heat of the moment may or may not be applicable advise.

As sailor of a different foiling cat, I might say - trick your mast top to sink, not to float, maybe with an easy way to re-seal it when you're racing. So in a racing context, there's support boats and a fleet around you, nd you don't want to waste time to a capsize. Any other time, let it sink, so you can swim to it safely.

Please try NOT to give such a wrong guidance, more if you don't have the experience. NEVER ever, if possible, let the mast sink. What a poor and without any base/experience on the matter advice to give. As Sam points you are not going to recover it, less being a carbon mast. 

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7 hours ago, mookiesurfs said:

I lost the boat.

Thanks All. I raced last night in more wind than anticipated but set the foils where I usually do.  Wow, that was a WILD ride. Too much lift. Moments of transcendent speed, lots of work, and two crashes. I liked it, and learned, but:

I lost the boat. It was on its side, and blew away from me faster than I could swim. Now, I am a competitive swimmer, and competed in the last two swimming world championships. If I couldn’t catch this boat, NOBODY could catch this boat. So yes, there I was, floating in the middle of nowhere as the boat headed for the horizon. That’s fatal, and unacceptable.

How can you attach yourself to the boat?  Can you use a positive clip-on trapeze? Remaining attached to the trapeze would solve the problem, even though the bungee breaks. What are the risks of a clip-on trapeze?

Yeah, I’m not dead, but I’m not going to place myself in a position of helplessness again, either. I was wearing a Zhik vest with a waterproof phone and hand-held VHF, but it was an alligator infested lake and getting dark, so time was of the essence. Turns out a waterproof phone doesn’t work well in the water, and inland beer can racers don’t monitor VHF. In the end, a friend racing a Hobie 21SE saw me and picked me up.

How do you stay with the boat?

 

That is very scary.

Glad you are safe.  Have you got the boat back?

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9 hours ago, mookiesurfs said:

I think we're all pretty comfortable with the concept of induced drag, and I framed my question poorly. What I intended to ask was if the induced drag penalty from generating lift while not foiling upwind was offset by reduced parasitic (form and skin) drag because the hull is riding a little higher in the water from that lift, although not foiling.

This is an probably an entirely anecdotal and intuitive answer that comes from experience, unless someone has a flow tank. That's all I was looking for, experienced and intuitive opinions.

I wanted these opinions so I could then decide if the time and effort penalty of resetting the boards was worth it. 

It's all moot if the boat blows away. How do you stay with the boat?

I can't say how different the results might be for an A-Cat, but here are some drag estimates for a Moth (with hull & foils) that might be of interest to you.

For this specific hull & set of foils, there seems to be little or no penalty for a small amount of lift at the lowest speeds, and increasing benefit to moderately higher CL values at the higher pre-takeoff speeds.

I hope the figure isn't too confusing. If so, I can elaborate on it later.

SemiFoilingDragEstimates.jpg.ff1aaa08947572b6fa327a72494e34db.jpg

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7 hours ago, k2mav said:

Please try NOT to give such a wrong guidance, more if you don't have the experience. NEVER ever, if possible, let the mast sink. What a poor and without any base/experience on the matter advice to give. As Sam points you are not going to recover it, less being a carbon mast. 

As I said, I'm not an a-cat sailor, so yeah, I qualified my experience. Smart readers will know what to do.

I sail several boats with carbon fiber mast, and they won't break even if they turtle. Are a cat masts so underbuilt they can't handle being turtled?

And, you seem to be more concerned about the mast than about the life of the sailor. Is that the right priority? 

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12 hours ago, martin 'hoff said:

As I said, I'm not an a-cat sailor, so yeah, I qualified my experience. Smart readers will know what to do.

I sail several boats with carbon fiber mast, and they won't break even if they turtle. Are a cat masts so underbuilt they can't handle being turtled?

And, you seem to be more concerned about the mast than about the life of the sailor. Is that the right priority? 

as an A-Cat sailor I would not like try to flood the mast on purpose if you like. The drift speed of a capsized A (given the mast is sealed) is no foiling phenomenon, likelihood to be substantially separated from your boat might have increased however.

Having said this I remember from the kind of german reference book on cat sailing (guess what, there are not too many:-) the authors (Sach brothers, F18) are postulating to actively turtle the boat on purpose. However they narrowed this to the case of one crew being with the boat and the other swimming  literally miles away. So obviously not possible on any single handed catamaran:-) For double handed cat classes I have no experience if that method is useful, but I could imagine if the crew on the boat cannot manage to get the boat up alone it sounds sensible.

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Dyneema bungie is the way to go.  Doesn't break and three runs under tramp should be sufficient.  I think I paid $20 for mine and have used it to pull myself back to the boat no problem.  Well worth it!

I personally am not a fan of the ball system for trapeze and haven't seen them be more reliable or safer, but that is personal preference.  I am a big fan of inspecting and maintaining trap systems to make sure they are reliable.  A worn line or other failure can break a tiller or much worse.

A friend of mine who used to sail on the ocean on his A used a carabiner tied to his harness that he could clip on the mainsheet / traveler.  I tried it and it felt awkward and there could be some downsides, but it did stop the possibility of separation. 

I have been on turtled larger cats and that comes with issues too like daggerboards and other gear disappearing.  

I have seen A sails where the mast had been in the bottom mud and the sail now stained.  It can happen and the mast can survive,.

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That is some brilliant advice! Martin mentioned dyneema bungee, which I had never heard of, so I ordered some. It’s reassuring to hear that it actually works the way I had hoped, and will hold under some load at least. I also ordered some double 18mm Carbos and will put 5 crossings in the tramp. That should settle the trap bungee breaking.

I decided against the trap ball attachment for now, because I could find no real endorsements of it, and there is some mild discontent with hooking up.

The carabiner/snap shackle to the mainsheet sounds promising. I’ll test that also as a backup until the foiling wrecks become fewer, less violent, and less spontaneous.

Windsurfers have a lot of neat harness and harness release gear, it turns out. Most of it is aimed at getting off the hook under load, which is not what I was looking for, but could be useful. However, they do have a rubber finger they call a “donkey dick” that holds the hook on to prevent inadvertently dropping off. I’m going to think about rigging something similar.

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Be careful on clipping onto the main sheet, if you fall off, all you do is tighten the main and the boat just wants to go faster, thus making it even harder to get back on the boat. A good example has been the recent experience of the Weta thread here on SA which basically towed the in water crew until the boat beached on a sand spit by memory.

Cheap skate way of making stretchy dyneema is use a 4mm Dyneema line with a 3mm bungie cord down the middle, stitched at either end, it pulls the line up to about a 1/3rd of its fully extended length and you can reach down and clip into a dedicated loop in the tramp.

 

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21 hours ago, mookiesurfs said:

That is some brilliant advice! Martin mentioned dyneema bungee, which I had never heard of, so I ordered some. It’s reassuring to hear that it actually works the way I had hoped, and will hold under some load at least. I also ordered some double 18mm Carbos and will put 5 crossings in the tramp. That should settle the trap bungee breaking.

I decided against the trap ball attachment for now, because I could find no real endorsements of it, and there is some mild discontent with hooking up.

The carabiner/snap shackle to the mainsheet sounds promising. I’ll test that also as a backup until the foiling wrecks become fewer, less violent, and less spontaneous.

Windsurfers have a lot of neat harness and harness release gear, it turns out. Most of it is aimed at getting off the hook under load, which is not what I was looking for, but could be useful. However, they do have a rubber finger they call a “donkey dick” that holds the hook on to prevent inadvertently dropping off. I’m going to think about rigging something similar.

Really love this forum and the  sharing of such useful things from all you guys!

Will also switch over to dyneema shock cord/bungee, also cause I am curious whether the promised effect of dyneema shell reduced friction. Read reviews which recommend that material as default for shockcord on dinghies/skiffs. Let's see...

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I have been using dyneema covered bungee for several years. In addition to the increased breaking strength, the bungee life is easily double that of conventional bungee. I don't think it necessarily runs more smoothly through the blocks, maybe a tad, but the exterior is a bit more textured than conventional bungee, so I would say that feature is a wash. Still, I highly recommend it for the increased useful life.

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On 7/23/2020 at 11:39 PM, mookiesurfs said:

I lost the boat.

Thanks All. I raced last night in more wind than anticipated but set the foils where I usually do.  Wow, that was a WILD ride. Too much lift. Moments of transcendent speed, lots of work, and two crashes. I liked it, and learned, but:

I lost the boat. It was on its side, and blew away from me faster than I could swim. Now, I am a competitive swimmer, and competed in the last two swimming world championships. If I couldn’t catch this boat, NOBODY could catch this boat. So yes, there I was, floating in the middle of nowhere as the boat headed for the horizon. That’s fatal, and unacceptable.

How can you attach yourself to the boat?  Can you use a positive clip-on trapeze? Remaining attached to the trapeze would solve the problem, even though the bungee breaks. What are the risks of a clip-on trapeze?

Yeah, I’m not dead, but I’m not going to place myself in a position of helplessness again, either. I was wearing a Zhik vest with a waterproof phone and hand-held VHF, but it was an alligator infested lake and getting dark, so time was of the essence. Turns out a waterproof phone doesn’t work well in the water, and inland beer can racers don’t monitor VHF. In the end, a friend racing a Hobie 21SE saw me and picked me up.

How do you stay with the boat?

 

I lost mine once when I fell off in a foiling gybe. There was no way I was going to catch it. Luckily I was rescued before it hit the rocks. For awhile I tried towing a rope behind the boat that I could grab if I lost hold. was ok in strong winds, but drag made it harder to get up on foils in light conditions. I ended up carrying a VHF in my vest

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The hurricane brought us nice freshening winds yesterday, so I went for a sail to try out some of the ideas for staying with the boat. For starters, clipping on to the mainsheet did not really work. What a spaghetti factory. I used a swiveling snapshackle on the harness with a quick release ball and lanyard, but never even tried jumping off to see what happens. After just a few tacks, the line situation was such a pia I decided the idea would not work, at least racing short courses. Maybe for the Worrel if you don’t  mind unclipping and reclipping after sorting lines on every long tack, but then you have would probably have chicken lines anyway.

Things that did work where the longer trapeze bungee (5 passes under the tramp with two 18mm Harken double blocks) and dialing down the foil lift. The VHF fit in the life vest ok, but the antenna kept stabbing me in the face until I turned it sideways. Today is the hurricane, tomorrow is 20-30 Kts steady. I’ll pass.

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On 7/24/2020 at 11:40 AM, martin 'hoff said:

As I said, I'm not an a-cat sailor, so yeah, I qualified my experience. Smart readers will know what to do.

I sail several boats with carbon fiber mast, and they won't break even if they turtle. Are a cat masts so underbuilt they can't handle being turtled?

And, you seem to be more concerned about the mast than about the life of the sailor. Is that the right priority? 

I know this is a bit late, but this is simply wrong. The advice is nothing to do with how strongly the masts are built.The advice is nothing to do with breaking your mast.; Your problem is that you do not have the experience to comment, because if you did, you would understand how wrong your comments are.

The problem with an A is that compared with any other single handed cat, the mast is ridiculously long. If you get water in the mast, you will not get the boat back upright. It is that simple. This is because of the lever effect of the weight of the water so far away from the righting moment you can provide. Therefore, a capsize with an unsealed mast guarantees that you will need outside assistance. You would be surprised at how little water is needed in the mast to make it impossible to get upright. It may not be a huge issue on a lake, so long as the shore isn't rock, but if you are blown onto rocks you break your mast and boat and maybe even place yourself in danger or if you are on the sea, and it is an offshore breeze, you are in very deep trouble. This is not a new issue for A's that has come about with carbon masts. It was probably even worse with alloy masts because they were so much heavier in the first place.

So on an A you have choices. You can allow water into your mast and get into significant trouble every time you capsize, or you keep it sealed and have to work out what to do in the very rare situations when you get separated from your boat. IMO, the first option means you cannot sail with a support boat while the second is manageable if you plan for it. So your "recommendation" is actually the one that puts the sailor most at risk.

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And after my rant above, now the real reason why I looked at this thread today........

Yesterday, I went for a sneaky mid week training session. I had done some maintenance under the trap to ensure that everything was working as it should so set out with 2 others in what seemed like great conditions. It soon became apparent that I had stuffed up and there was an issue with the under tramp mainsheet system.  It felt very stiff and I couldn't pull the mainsheet fully on. The one downside of an under tramp system is that you cannot sort issues out on the water, but this was the first time in 4 years i had an issue. Knowing I would lose most or all of the day if i went back in to sort it out, I decided to continue sailing to see if I could steer around the issue. I only had a small range of effective mainsheet, although i could ease it enough to get up on foils downwind and just get it in enough once up on foils. What i couldn't do was play the sheet, so once I was up and running, all I could do was steer. It was not fast.

What this reminded me of is 2 things. First, as i have said before, the biggest issue for most when they start foiling is not moving enough sheet. You cannot steer around this problem as you need to keep the boat level and you need to make sure you do not overpower the foils. So if you believe you boat is set up reasonably well but are struggling to keep the boat on foils through gusts and lulls, look the amount you are adjusting the sheet. I did go in and sort the issue and went out again for a short time to check it was working, and what struck me was that while I was constantly trimming, it wasn't whole armfuls of sheet but for most of the time. it was just pulling and easing by the amount you can move your arm. Yes, there are times you need to sheet far more than that, but what was clear is that those relative small amount of sheeting coupled with correct steering is what is needed. 

The other thing is that in so many cases, I find people who are sailing with very sub-optimal mainsheet systems.The obvious thing is to ensure your blocks and ratchets are working really well, and that the rope is threaded correctly for minimal friction. However, what i think far to few people focus on is the rope itself. Many sail with rope that is either too thick, too stiff or too old. The too old is something many never think of. Depending on how often you sail and the exact type of rope you use, you probably should be changing your mainsheet every season, while I know some who change it every 6 months. I don't need to because I use very expensive but very good rope (Marlow Excel Fusion) and I get 2 seasons out of a mainsheet. I also use 7mm which for some, might seem a bit small (it is available in 8mm), but when I first switched to it, that was all I could get and it is now what I am used to.

The bottom line is that you stand no chance of developing your skills if your mainsheet system isn't 100%

 

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On 8/19/2020 at 2:43 AM, SimonN said:

it was just pulling and easing by the amount you can move your arm.

At what purchase ratio? On the 7mm diameter, what are corresponding sheave sizes In the under deck systems (if not using some magic wheel)? I still have sheet above deck and a combination of 57ish outer/40ish inner sheaves and a 9mm mid part spliced to a 4mm Dyneema taper towards the fixed point.sometimes I already feel 9mm is too slow for fast teaction although it is a nice soft rope. Also I am not too happy with the autoratchet release. Probably this mechanism is aging as well?

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16 hours ago, Butenbremer said:

At what purchase ratio? On the 7mm diameter, what are corresponding sheave sizes In the under deck systems (if not using some magic wheel)? I still have sheet above deck and a combination of 57ish outer/40ish inner sheaves and a 9mm mid part spliced to a 4mm Dyneema taper towards the fixed point.sometimes I already feel 9mm is too slow for fast teaction although it is a nice soft rope. Also I am not too happy with the autoratchet release. Probably this mechanism is aging as well?

While I don't know what purchase the DNA wheel system gives you, I do know that all the Exploders now have 10:1 purchase - 2:1 above deck and 5:1 under the deck. I have 40mm blocks under the deck, but I know some who insist on the bigger ones. I also have 2 autoratchets, one on the deck and one under the deck and the one below the deck is a Harken that gives you 1.5 times grip. I need it due to my age and strength, because without that, i could not sheet the main hard enough foiling upwind. Mine works well enough but I admit it is on the very edge of being too grippy.  2 ratchets in the system isn't just for wimps like me - I know somebody who won a recent worlds with 2, although they did have standard grip. You can also get the Harken autoratchets with high threshold engagement which delays the point at which it starts to work.  What I am certain of is that you need 10:1 to be able to sail a foiling A properly. I experimented with 12:1, which was very nice but was too much rope and too much friction in winds below 8 knots. If I knew I was always sailing about 10 knots, I would seriously consider it. Others in my training group tried my boat and were surprised how good it was when there was breeze. In short, I think 10:1 is not only the optimum, but also the minimum purchase.

9mm seems to me to be way too thick, whatever rope you are using. You can use 8mm if it is the right stuff like the Marlow I use, but again, if it isn't soft enough or gets old and stiff, you will have issues. I also suspect that 9mm could have an impact on the ratchet and if it is a bit old, while it may feel soft, it might have got a bit smooth. Also check the "teeth" of your ratchet for wear.

I believe that while the under deck system has least friction, you can make an above deck system work with the right blocks and the right sheet. Do not under estimate the improvements from a new mainsheet of the right material and ensuring your blocks are in top condition. Although not suggesting you need to buy one, there is a reason why the Olympic Nacra 17 guys have mainsheet systems that cost about $1700!

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Where do like to stand to to get up on the foils, downwind? Currently I'm always in the back footstrap to start foiling and continue foiling, but I've seen photos of people much further forward, and have read about moving fore and aft to adjust the boat. I'd like to be further forward, it's more comfortable and a better place to handle the boat from.

Can you get up on foils from amidship, downwind? Or do you move forward?

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On 8/30/2020 at 6:25 AM, mookiesurfs said:

Where do like to stand to to get up on the foils, downwind? Currently I'm always in the back footstrap to start foiling and continue foiling, but I've seen photos of people much further forward, and have read about moving fore and aft to adjust the boat. I'd like to be further forward, it's more comfortable and a better place to handle the boat from.

Can you get up on foils from amidship, downwind? Or do you move forward?

I suspect the photos you have seen of people further forward are when they are foiling upwind. Downwind, you should be in the back footstrap and most people will stay in that strap and move their other foot forward and back as needed. If you are super confident in your boat handling and the set up of your boat, then maybe the straps aren't so important and you can "walk the gunwale" a bit more, but I haven't seen any benefit from doing so and you are far more likely to swing around the front.

My technique for getting up on foils downwind is pretty simple. From sitting on the side, you go out as the hull lifts off the water, which tends to level the boat out until you can sheet and steer properly which then makes the hull lift again. As it lifts, I take a step back and put my rear foot into the rear footstrap and at the same time, I bear away a little and ease the sheet to get the boat absolutely flat. At this stage, my feet are only 12 inches apart. As the boat lifts off, you will need to sheet on or else it will come over on top of you, but if you sheet too soon, the foils load up and you come off the foils. The boat rises and begins to reach "cruising height" and then you need to move your front foot forward to level off the flight. Bow up attitude is not fast. I end up with my feet about 2.5 to 3 feet apart but I leave the rear foot in the strap. I will then  fine tune ride height and bow up or down with a mix of mainsheet and front foot position, plus a bit of steering as the wind pressure changes. If I need to go any further forward to get the bow down, it probably means I am running too much lift on the centreboards. 

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I do not want to derail this conversation, but above, you all were talking about trapeze bungee systems and making multiple passes under the trampoline.  After re-doing my bungees far too many times, I'd like to get a proper setup under the trampoline.  Can anyone point me to a diagram or some information on how to make these back and forth passes and where to place the blocks?  
I will order the dyneema bungee at a later time, but I need to get back on the water this weekend, so I will be fixing it with the regular stuff for now.
Thanks in advance for any help on this.

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3 hours ago, DialedN_07 said:

I do not want to derail this conversation, but above, you all were talking about trapeze bungee systems and making multiple passes under the trampoline.  After re-doing my bungees far too many times, I'd like to get a proper setup under the trampoline.  Can anyone point me to a diagram or some information on how to make these back and forth passes and where to place the blocks?  
I will order the dyneema bungee at a later time, but I need to get back on the water this weekend, so I will be fixing it with the regular stuff for now.
Thanks in advance for any help on this.

It very much depends on what you have going on under the tramp. If you have your mainsheet under the tramp, then you need to make sure the bungee cannot get caught up in it and you might lead the bungee uip and down the sides - through the eye in the tramp, down the side to the back, through a block and then up the side to the front, across the boat (just in front of the beam) and back down the side to the back and up to the eye (I hope that makes sense!!). Alternatively, if it won't foul the mainsheet, you can go through the eye, across the boat to the other side, through a block, back across the boat and through another block and then back through the tramp eye.

Hope that helps.

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5 hours ago, DialedN_07 said:

I do not want to derail this conversation, but above, you all were talking about trapeze bungee systems and making multiple passes under the trampoline.  After re-doing my bungees far too many times, I'd like to get a proper setup under the trampoline.  Can anyone point me to a diagram or some information on how to make these back and forth passes and where to place the blocks?  
I will order the dyneema bungee at a later time, but I need to get back on the water this weekend, so I will be fixing it with the regular stuff for now.
Thanks in advance for any help on this.

I removed the existing single blocks and installed double blocks in the same location. On my boat, it is the aft most bungee, and runs back and forth 5 times between the hulls, right about where the trap lines are.

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12 hours ago, SimonN said:

It very much depends on what you have going on under the tramp. If you have your mainsheet under the tramp, then you need to make sure the bungee cannot get caught up in it and you might lead the bungee uip and down the sides - through the eye in the tramp, down the side to the back, through a block and then up the side to the front, across the boat (just in front of the beam) and back down the side to the back and up to the eye (I hope that makes sense!!). Alternatively, if it won't foul the mainsheet, you can go through the eye, across the boat to the other side, through a block, back across the boat and through another block and then back through the tramp eye.

Hope that helps.

It does make sense.  I'm on an F16 and I'm just trying to work out in my mind where I'm attaching the blocks.  I guess I could go diagonally back to the rear beam area, or up to the dolphin striker, but I don't think there is anywhere else to attach a micro block.

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On 9/1/2020 at 1:55 PM, DialedN_07 said:

It does make sense.  I'm on an F16 and I'm just trying to work out in my mind where I'm attaching the blocks.  I guess I could go diagonally back to the rear beam area, or up to the dolphin striker, but I don't think there is anywhere else to attach a micro block.

SS rings are far cheaper and work just as well for the bungy, also think about back to front rather than side to side, also a simple pass to the opposite side can save a lot of passes as only ever one side gets used at a time, the F16's doesn't quite have the knitting underneath of the A's. Also use say 2 x 3mm bungy as small diameters stretch much more than larger diameters.

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43 minutes ago, Waynemarlow said:

SS rings are far cheaper and work just as well for the bungy, also think about back to front rather than side to side, also a simple pass to the opposite side can save a lot of passes as only ever one side gets used at a time, the F16's doesn't quite have the knitting underneath of the A's. Also use say 2 x 3mm bungy as small diameters stretch much more than larger diameters.

I have a SS ring currently that I use for my spin halyard/retrieval line to keep it taught against the tramp.  Yes, fore and aft passes will work much better than side to side as there is nowhere to tie off to against the hulls.
Thanks, I'll take a look when I get home.

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On 9/3/2020 at 4:43 PM, DialedN_07 said:

Yes, fore and aft passes will work much better than side to side as there is nowhere to tie off to against the hulls.

On my F16 we used a simple 2 x 3mm bungy leading from one Trapeze down through an eye in the tramp, across the tramp, through another eye and back up to the opposite trapeze, there was enough length to give the right amount of stretch.

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6 hours ago, Waynemarlow said:

On my F16 we used a simple 2 x 3mm bungy leading from one Trapeze down through an eye in the tramp, across the tramp, through another eye and back up to the opposite trapeze, there was enough length to give the right amount of stretch.

I don't believe this is enough on an A. You would have about 3m of shock cord, which needs to be under a bit of tension to hold the trapeze in place and you therefore don't get full the benefit of the 100% stretch capability. When you are at the very back of the boat you have well over 2m of shock cord coming out of the eye, so you are beginning to approach the maximum stretch, but even at 75%, that's more forward pull than you want. Then there is the situation of being thrown forward, around the bow, which happens to the best occasionally. i think you will get to the end of the limit of the stretch and break the cord, unless you have dyneema but even them, you are working at the limit.

You also lose some of the stretch capability because of the friction through the eyes and through a SS ring. I personally wouldn't use a SS ring for a 180 degree turn in shock cord. A proper thimble improves matters but there are still loses and for the sake of a few dollars, i would always use a block. It doesn't have to be some expensive ball bearing one, with Ronstan offering a suitable one for under AU$10. When you consider how much an A costs, how important staying on your feet is and the penalty for breaking your shock cord (lose the rest of the day), why not do it properly?

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A’s must be special boats to need special measures I guess, sort of A Class snobbery :D

Yet to find a bungey that will not break when you go around the front of the mast in a pitch pole but then as I’ve had only ever 1 pitch pole in over 8 years of non foiling sailing on both a F16 and a modified A Class, I guess that scenario is the one I’m least worried about.:rolleyes:

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On 8/18/2020 at 5:43 PM, SimonN said:

On our F18 and F16 we place a block at each rear corner of the tramp. Run cord from eyelet across boat to block, along rear trampoline to the other block, then back across boat to other eyelet. This is for skippers. Crew runs in beam. 
Not enough for my A, but works well for the F boats. 

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15 hours ago, Waynemarlow said:

A’s must be special boats to need special measures I guess, sort of A Class snobbery :D

Yet to find a bungey that will not break when you go around the front of the mast in a pitch pole but then as I’ve had only ever 1 pitch pole in over 8 years of non foiling sailing on both a F16 and a modified A Class, I guess that scenario is the one I’m least worried about.:rolleyes:

I am not sure it's about the A needing special measures. Your post suggests that even with the boats you sail, you haven't got your system correct. I think in 8 years of A Class sailing and many trips around the forestays, I have only broken 1 shockcord. It's a case of having enough shockcord in the system so that you don't reach the end of the stretch capability. By adding dyneema shockcord as well, it should take a really extreme event to get a breakage. In the past, we used to run 2 shockcords so that if one broke, you could still finish the day (that's how common breakage used to be) but for the last couple of years, we have only been running one and I think that is because we now have enough give in the system and strong enough cord. I wish I could say it is because we no longer go around the front, but that would be a lie!

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7 hours ago, SimonN said:

I am not sure it's about the A needing special measures. Your post suggests that even with the boats you sail, you haven't got your system correct. I think in 8 years of A Class sailing and many trips around the forestays, I have only broken 1 shockcord. It's a case of having enough shockcord in the system so that you don't reach the end of the stretch capability. By adding dyneema shockcord as well, it should take a really extreme event to get a breakage. In the past, we used to run 2 shockcords so that if one broke, you could still finish the day (that's how common breakage used to be) but for the last couple of years, we have only been running one and I think that is because we now have enough give in the system and strong enough cord. I wish I could say it is because we no longer go around the front, but that would be a lie!

Interesting that the A's do the nose dive dance so often, we played for ages on front spinny pole length together with the T foils from about 2000 on the Stealth F16's and with the Spinny even way over powered and you are up to the front beam in the ditch, you just do not see the pitch poles you are talking about. I think I'll take the simplified bungy system we have and take the 1 break in 8 years.

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2 hours ago, Waynemarlow said:

Interesting that the A's do the nose dive dance so often, we played for ages on front spinny pole length together with the T foils from about 2000 on the Stealth F16's and with the Spinny even way over powered and you are up to the front beam in the ditch, you just do not see the pitch poles you are talking about. I think I'll take the simplified bungy system we have and take the 1 break in 8 years.

He’s talking about foilers not floaters. They crash for very different reasons. 

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It is of limited value comparing A Class cats to any other cats.  A Cats, foiling or floating, at 75kg, are very responsive, and in over 20 knots, twitchy,  much more so than F16's, stealth, shadow, hobie, nacra etc.   Honestly, they are worth the swims, but if you don't race an A Cat, you don't race a boat 'similar' to an A Cat.  Call it snobbery if you like, A Cat sailors are the least snobbish, most helpful sailors I have met.  One thing A Cat sailors are quite good at, is inventive ingenuity, the control systems have evolved through countless generations, if A Cats use 8m of trapeze bungee and ball blocks, there is a good reason.  If you're not going round the forestay once a year, you're not trying hard enough, broken bungees are a crap reason to go ashore.

 

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15 hours ago, Waynemarlow said:

Interesting that the A's do the nose dive dance so often, 

13 hours ago, WetnWild said:

He’s talking about foilers not floaters. They crash for very different reasons. 

 

WnW nails it, as usual.Seeing we were talking about foilers, I discussed what we do in foilers. And for the record, the reason why we go around the front is rarely due to a nose dive but more about sudden acceleration and/or deceleration, or simply getting washed off the side of the boat. 

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