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Post by richy on Dec 16, 2014 9:18:18 GMT
Recently purchased a Sunfast 37. Any set-up tips very much appreciated. It has a fixed three blade prop. Is it worth considering a folding one for racing? Also what IRC handicap is she likely to be given?
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Post by MalcolmP on Dec 16, 2014 10:00:04 GMT
Congratulations on the SF37 and welcome to the forum. That fixed prop will slow you down by at least 0.5 knot compared with most folders. There are quite a few threads on the forum already about the various merits eg: jeanneau.proboards.com/thread/3302/folding-prop-recommendations but do get rid of the fixed, presuming that you will be racing and not motoring a lot then a good quality folder will be the best - you will need to check the gearbox ratio (on plate on side) shaft size, engine HP etc before you can get reliable quotes Will leave the racers to talk to you about IRC rating, but you also need to think about sails as the most important part of a go faster package - quite a few recent threads on this forum as well Malcolm |
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Post by sitara on Dec 16, 2014 22:18:15 GMT
Pointing ability will also improve with a folder. I added a feathering prop at the start of last season and the results were very obvious, faster, pointing higher and smoother. As Malcolm said get all the necessary data together about the boat and I would suggest getting quotes form a few manufactures to check their estimates for prop size for consistency. I went for the feathering prop because it did give me the option to adjust pitch. My old fixed prop (factory fitted) was over size and would not allow the engine to rev out to max revs under load which made my mechanic very unhappy
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Post by dbostrom on Dec 17, 2014 6:14:07 GMT
Maybe a good subject for a hints and tips roundup? Useful, fairly scientific review of many folding props by Yachting Monthly is here. |
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Post by hoppy on Dec 17, 2014 7:49:53 GMT
I guess that there is no debate as to whether it's worth getting a folding prop for racing, it's a definite yes. I also think it's a definite yes even for cruising if you do any sort of distance sailing. The point to debate is which prop is best  The link posted by dbostrom is a good starting point. |
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Post by On y va on Dec 17, 2014 13:36:07 GMT
I guess that there is no debate as to whether it's worth getting a folding prop for racing, it's a definite yes. I also think it's a definite yes even for cruising if you do any sort of distance sailing. The point to debate is which prop is best The link posted by dbostrom is a good starting point. Yes, except that test is 5 years old. And several prop manufacturers have updated their props. I.e. Maxprop Easy. But, a test is one thing, practicality and reliabilty another and let's not forget, shaft or saildrive. I.e a 3 or 4 bladed Volvo prop is cool for racing, but sucks for cruising. As the slightest growth makes them vibrate and cause substantial extra fuel consumption. To give an example: I took an Oyster 46 with a 4 bladed Volvo folding prop from Palma de Mallorca to Corfu. the prop was squeeky clean, so was the hull. We motorsailed nearly all the way. We used 675 litres of fuel. The delivery crew who brought the boat back from Greece to Palma (with 100 miles more distance), but with a fauled prop used 1820 litres!!!!! also not being able to run any faster than 6 knots. I.e. the new Maxprops Easy have a damping system in them, which dampens the shock onto the gearbox when the prop opens. Very nice, but also much more complication inside the prop, besides...it will wear over time. If you have a Volvo saildrive, you don't need that dampening system anyway. On a Yanmar up to 2012 you do. Other consideration: if you have a saildrive, the shafts are relatively thin. Most folding and or vane props have huge centre hubs and the blades positioned at the end of that hub. On a saildrive, this can cause exessive vibrations, esp with a little growth on the prop. So then it may be an idea to get a short prop like a Featherstream (by Darglow Engineering UK). Also being able to change your pitch underwater (without having to lift the boat out of the water) or not can be useful. With some props you can, with others you can't. Especially for long distance cruisers this can be useful. So really look at what your engine/gearbox and or drive situation is and what your intended use is before you decide. Don't just look at the tests. |
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Post by dbostrom on Dec 17, 2014 18:40:28 GMT
There we go: debate provided!  Seems as though if the Oyster being returned had a fouled prop, the hull would be a factor as well; impossible to fully sort out the variables there but I'd still offer that the hull would be larger issue than the prop. As well, a fixed prop would not be immune to fouling. So I'm not sure the Oyster example is very useful? More anecdotal data to argue over: our boat (SO39i) has a Flexofold with about 2,500 hours on it, coupled to the usual Yanmar 3JH5E. The boat just went through survey and the prop was found to be in excellent condition, with no obvious signs of wear. It has not required repair since being installed when the boat was commissioned in 2010. The boat has been in service about 1/4 of hours with the owner skippering, the balance of the time in the hands of (carefully vetted) charter guest skippers. I've found the Flexofold to deliver pleasingly authoritative thrust in forward and reverse and to exhibit very scanty propwalk. As with the other props in the review by YM, the position of the Flexofold in rankings varies a bit by metric. It does seem plainly intuitive that a fixed blade prop striking an object is probably going to deliver better survival (or at least limp home) statistics than a folding model. That might be a deciding factor in choosing a prop suitable for whatever mission is being contemplated; a broken prop is no use no matter how good it was before being broken. It's true that the YM article is becoming long in the teeth. Against that, some of these designs have been largely static for a couple of decades. |
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Post by so36idavid on Dec 18, 2014 0:13:46 GMT
Pointing ability will also improve with a folder. I added a feathering prop at the start of last season and the results were very obvious, faster, pointing higher and smoother. What prop did you add? Thx |
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Post by MartyB on Dec 18, 2014 4:05:11 GMT
I would also add, dump any Sta set/yacht braid lines used as halyards or sheets, Unless for really light winds under say 10 knots or so. Sta set typically has a 3-4% stretch at 15% breaking strength, vs a dynema based line with .7-.9% at 20% breaking strength. You can also go a size smaller and still have more breaking strength in the line, which will save some weight aloft.
Also a laminate sail is a must overall vs Dacron. Again lighter cloth, and lighter sails overall, so less weight aloft, better pointing, less stretch in gust, better for light winds, reefing comes 2-4 knots higher in wind speed. You do not need to go to a string style ie Norths 3dl, ullman fiberpath, but some of the lower priced true laminate will do better than a Dacron or Dacron Mylar blend sail.
Hard paint and fairing the hull and keel will also help with some speed, and pointing ability also.
Reduce ANY and all non essential needs below in the cabins unless needed to race. Go with the minimum sized anchor/rode pkg you need up front. Do not have an all chain rode. For my 28' 6500 lbs Arcadia, that is a 5.5 lb anchor, and total 11.25 lbs of road, anchor and chain. Most cruisers would have at least a 15-20 lb anchor, 30-50' of chain and 150 minimum of road, total in the 40-60 lbs range. Weight at the ends can hobby horse your boat, so it will not sail as well, point etc. Not sure where you are at, ie Europe or US, in the US/north america phrf is more common. The minimum anchor is overall boat length divided by 17 then cubed. My boat (30/17)=1.765x1.765x1.765 = 5.498 lbs, then overall wt of pkg is LOA squared divided by 80. so 30x30 = 900/80 = 11.25 lbs total With 150' minimum of rode with sufficient strength to handle the load of the boat.
From a folding/feathering prop perspective. You typically gain .5-.75 knots of boat speed. For me going from 6 to 6.5 knots is a gain going from a 10 min mile to a 9.23 min mile. I get a 9 sec lowered rating/credit for a fixed 2 blade, and 12 secs for a fixed 3 blade. But I literally gained over 45 secs a mile in actual boat speed! by going with a nonfixed prop.
Hope some of this helps.
Marty
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Post by sitara on Dec 18, 2014 5:02:37 GMT
Hi So36idavid,
I fitted the Seahawk Autostream propeller. Main reasons were ability to adjust all blades with one set screw, stainless steel construction, and I could collect it from the local manufacturer. Other contenders were the Kiwi prop and the Gori and Flex-o-fold folders. I have lost some boat speed under power but as I can now get maximum engine revs under load (same as in neutral) there is some scope to increase the pitch and boat speed. The pitch setting for reverse is quite fine (but also adjustable) so I have to use a lot more revs for stopping, the plus being very little prop walk.
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Post by On y va on Dec 18, 2014 15:24:38 GMT
There we go: debate provided! Seems as though if the Oyster being returned had a fouled prop, the hull would be a factor as well; impossible to fully sort out the variables there but I'd still offer that the hull would be larger issue than the prop. As well, a fixed prop would not be immune to fouling. So I'm not sure the Oyster example is very useful? More anecdotal data to argue over: our boat (SO39i) has a Flexofold with about 2,500 hours on it, coupled to the usual Yanmar 3JH5E. The boat just went through survey and the prop was found to be in excellent condition, with no obvious signs of wear. It has not required repair since being installed when the boat was commissioned in 2010. The boat has been in service about 1/4 of hours with the owner skippering, the balance of the time in the hands of (carefully vetted) charter guest skippers. I've found the Flexofold to deliver pleasingly authoritative thrust in forward and reverse and to exhibit very scanty propwalk. As with the other props in the review by YM, the position of the Flexofold in rankings varies a bit by metric. It does seem plainly intuitive that a fixed blade prop striking an object is probably going to deliver better survival (or at least limp home) statistics than a folding model. That might be a deciding factor in choosing a prop suitable for whatever mission is being contemplated; a broken prop is no use no matter how good it was before being broken. It's true that the YM article is becoming long in the teeth. Against that, some of these designs have been largely static for a couple of decades. -------------------------------------------------------------------- Well, why I mentioned the Oyster trip, is because I am trying to say that a squeeky clean prop might perform well, but some props are much more affected by marine growth than others. That you never see in a test, but is the reality for most people owning a boat. I don´t know many people that scrub their prop clean every month. I have on average about 12 sailing yachts in my service-management, so I have a fair idea of what works or doesn´t work in reality. So tests, wonderful marketing and swooshy websites with lovely animation videos don´t mean that much to me. I.e. the prop featured in an add on this very website, I would not go near ever again. An opinion purely based on experiences. |
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Post by dbostrom on Dec 18, 2014 19:42:04 GMT
Ah, now I get what you're saying about different designs being more or less affected by a given amount of growth, On y va. That's a good insight. As well, you're more or less running a real-world lab with a decent population of experimental subjects so that does count for a lot. Would be very interesting to see bollard pull tests etc. done with the same group of props tested by YM, after being nicely fouled. That's a Practical Sailor kind of thing. Brutally expensive test suite to arrange, though. "Join in, let your boat become heavily fouled-- you'll be nicely thanked."  |
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Post by On y va on Dec 19, 2014 9:53:15 GMT
For a serious regatta sailor it doesn't really matter, as long is the prop as slippery as possible when folded/vaned. His/her prop and hull will be cleaned regularly. The guy who just uses the engine to get out of and back into a marina, for them the affect it doesn't really matter either.
However, for people that venture and especially long distance sailors, a poorly performing prop can be a total nuisance and in the end rather costly (as per the Oyster example I gave). I am a long distance sailor, hence I went for a 3 bladed 19" Maxprop. In my experience the least affected by marine growth. Unfortunately I have the classic, so pitch setting is not as simple. But even with substantial growth on it, it still performs fairly well.
The debate about a fixed prop versus folding or vane in regards to hitting something is correct. The fixed prop gives you most survival changes. But to me that is the only advantage. As the permantly turning of the prop whilst sailing (plus the whining noise) is a huge disadvantage for long(er) distance sailors, unless you have a shaft generator. Also a fixed prop has much more chance of catching nets or plastic bags etc. In the Med where I sail, a permanent issue/danger.
Anyway, each to their own. As long as you are happy.
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Post by richy on Dec 20, 2014 22:37:25 GMT
"Just uses the engine to get out of the marina..." That's me. You've convinced me re. Folding prop and thanks all for the excellent tips. How about sail plan? Initially I was planning to stick with the standard roller furling genoa (about 110%??) but I am aware that some opt for a much bigger overlapping genoa. Is the extra sail area likely to outweigh the handicap?
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Post by hoppy on Dec 21, 2014 13:44:19 GMT
"Just uses the engine to get out of the marina..." That's me. You've convinced me re. Folding prop and thanks all for the excellent tips. How about sail plan? Initially I was planning to stick with the standard roller furling genoa (about 110%??) but I am aware that some opt for a much bigger overlapping genoa. Is the extra sail area likely to outweigh the handicap? Depending on where you sail, perhaps you might consider keeping the 110% genoa (upgrade to some fancy laminates) and get a code 0. The code 0, I believe does not affect the handicap. |
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Post by MartyB on Dec 21, 2014 21:58:11 GMT
In some regions, being as a code 0 is not connected to a head stay, it counts as a spinnaker, assuming you have the largest spin available for the base rating of ones boat, the code 0 does not effect the rating. BUT, if you are trying to sail non-flying/white sails or some other equal version. A code 0 would effect your rating, by making it lower, faster or some other equal that gives you less time to get from start to finish.
Marty
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The link posted by dbostrom is a good starting point.
