Swallow Yachts Association
Swallow Yachts Forum => General Discussion => Topic started by: johnguy on 02 Aug 2018, 13:16
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I have a one year old Bre sail no 55 Mk 2 with bowsprit etc. I race it casually with Cardiff Bay Yacht Club and notice that although we are fast downwind we can never point as well on the upwind legs as most of the varied competition (cruisers of various ages and sizes), although we do always thrash the Old Gaffers.
I'm not a racer by pedigree and we do do quite well overall in the cruiser races but I would like to improve this one aspect of our performance.
We have fiddled with jib cars forward or aft, kicker on hard or soft or off, mizzen in hard or less hard but can't seem to nail the best set up for consistent good pointing upwind.
Any set up tips from people who race on best starting point for good pointing and upwind performance for a Bre with MK2 rig?
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Would you mind broadening this discussion? I have the Gunter, boomed jib BR20. We don't point so we'll either.
Any advice would be most appreciated.
John
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John
In my experience with my BR20 (Bermudan shape main with sprit boom) some of my upwind performance is lost due to leeway. I think I’m sailing her hard, lots of heel and spray only to be out performed by flatter calmer boats. My jib is self-tacking so no jib cars to fiddle with but I do have tell-tales on my jib and semi battened main which I use and rely on, these tell me I have the jib shape right and whether the sails are in hard enough for maximum drive. With no portable ballast (crew) most of the times I sail I can only keep the boat flatter with spilling and filling the main as efficiently as i can.
Water ballast is not mentioned in your post, i guess on a BRe you normally fill the tanks.
Matt did post an article on Mast Rake some time ago for BR and BRe it might be worth checking yours 2-3 degrees aft I seem to remember is the suggestion, mostly affecting rudder helm but as you know rudder helm will make a big difference to boat speed.
Can't comment on the correct setting of the kicker as I don't have one and never used one however a quick trawl of the internet brought up some very in depth articles on the use of the kicker and sail performance.
Look forward to reading others experience on this topic.
Peter C
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I find telltales very useful, especially on the jib. There’s more on telltales (and sail trim) in the library http://www.swallowyachtsassociation.org/?page_id=282.
Matt's advice to avoid backwinding the sails in reasonable winds was to keep the jibsheet fairly relaxed, have the main sheeted in a bit more and the mizzen sheeted in harder still.
In light airs, my boat seems to point a bit higher if I improvise an informal mainsheet traveller. Try grabbing a fistful of the mainsheet above the lower block in the cockpit and hoik it to windward. Then let out enough mainsheet so that the boom is more or less amidships. If you want a more formal arrangement, there’s this http://www.swallowyachtsassociation.org/smf/index.php/topic,428.msg2325.html#msg2325. A jib topping lift may also help with jib shape in light winds - see http://www.swallowyachtsassociation.org/smf/index.php/topic,1217.msg8610.html#msg8610.
And as Peter says, keep the boat as flat as you can in stronger winds, preferably by reefing the mainsail first (if in a race and with crew aboard) before putting in the water ballast as a last resort.
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Thanks Peter/Graham, very interesting. We will try sitting flatter and paying more attention to telltales. Kicker is a mystery to me, I can't figure it out. It definitely changes the sail shape but I'm never sure if for better or worse.
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Peter, I usually sail ballast in, as I found with it out we made a lot of leeway. Plus I'm sometimes alone and it is easier and safer that way. Also on short round the cans courses we don't skid round the corners so much. Anyway it is hopeless to think of getting the ballast out properly when the boat lives in the water, a nearly empty with consequent free surface is the best that I can achieve.
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John
This is one of the articles i found on the subject
http://www.ybw.com/forums/showthread.php?117515-what-s-that-kicker-thing-for
Always willing to read anything to do with boats, not that i will remember the content and can't put any of this into practice on my boat.
Peter C
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Thanks Peter, very interesting. I've read up some books too, which more or less say the same. But I wondered what specific BRe comments there were, as I have found it difficult to measure what works best for me. I think the problem is really in my mind, I'm not a racer at heart, only come to it now in old age and looking for short cuts to performance when I should be looking more intently at the sails... on the Swallow Raid this year we were pointing as well as the other BRes so I guess that is it, just have to accept that and hope for more downwind legs to burn off the opposition.
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This is a topic which has occupied my mind on and off this summer. After an overhaul and string replacement I had to experiment with shroud length. I found mast rake to be critical when considering upwind behaviour. I spent a day with unpleasant lee helm and struggling to better 45 degrees to wind. Shortening stays made a dramatic improvement, although my first attempt led to great performance on port tack and lousy starboard - 2cm difference in shroud length.
Otherwise it is the usual things - mainsail shape, jib luff tension, weight distribution fore and aft.
Robin
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This is a topic which has occupied my mind on and off this summer. After an overhaul and string replacement I had to experiment with shroud length. I found mast rake to be critical when considering upwind behaviour....shortening stays made a dramatic improvement, although my first attempt led to great performance on port tack and lousy starboard - 2cm difference in shroud length.
Robin
I have shortened my shroud cords P& S, by the same amount, as I found that my boats rigging had barely bedded in from new, ah
Having been sailed so little by original owner. There has been a lot of strech after a couple of windy coastal passges of a few hours. Jib halyard strech was borderline scary! Have binned that now for cruising dyneema instead.
Pointing much improved, weather helm quite nicely balanced now. No idea how i point relative to other BRe as yet.
I used the shroud eye terminations as reference points, and it did cross my mind that i really ought to check wire lengths against one another. Have not done so as yet.
Robin. Were your shroud wires of different lengths from factory?
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No Simon - I'm afraid it was my inadequate adjustments made on a pontoon on a windy day.
I am undecided on the matter of dyneema vs polyester halyard. It is not possible to achieve rig tension in the manner of fixed mast boats. Without stays attached by hard connection to the chainplate there will always be some give, and I worry about aggressive tensioning of the jib ie by means of a 2:1 block. The mast jib strap is only riveted on.
There are clearly benefits in performance yachts, and greater weight savings aloft, but I'm less convinced in our modest craft. That said I am forever tightening the cunningham in the main when the luff sags in strong winds. Perhaps dyneema would cure this ill.
Looks like a visit to the chandlery £££
Robin
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This is my third season with BRe 047 Whimbrel and my experience of 'racing' with it is at at three successive Falmouth Swallow Raids.
The first season we made good starts but always lost out on the windward legs - I put this down to inexperience. I always thought my mast was a bit raked forward but I was assured that this looked all right. In the second Falmouth Raid it was easy to see when all moored up on the pontoon that our mast rake was indeed forward of all the rest. So at the end of last season and absolutely convinced I was sailing with lee helm I took mast rake measurements but wondered how I would be able to make accurate adjustments just using the shroud lashings. So I replaced them with bottlescrews and adjusted the mast to have a couple of degrees rake aft and again took measurements.
At this last Swallow Raid the boat was going as well to windward as any of the others and indeed the boat tacks faster as we are not having to overcome lee helm just to tack!
So going on Swallow Raids is a good way of confirming tuning before then going out to sail in handicap fleets and not really having a clue as to real performance. Same goes for spinnaker handling too! Learned a lot on the raids!
RayS
Bre 047 Whimbrel
PS (The measurement system I used is one used in Wayfarers and many other classes I assume where you take a tape up to near the top of the mast with the main halyard and write down the figure when the tape is held to the middle of the gooseneck. Then take the tape back to the top rear edge of the transom and log that measurement. It is useful if the class agrees a standard distance to take the tape up from the gooseneck so that we can all compare measurements against each other. Maybe Swallow Yachts have this measurement?
While the tape is up it is also easy to take it to the transom corners and shrouds anchor points to check the mast is vertical from side to side. )
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This was posted sometime ago when mast rake was topical
http://www.swallowyachtsassociation.org/smf/index.php/topic,1507.msg11024.html#msg11024
Peter C
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My Dyneema jib halyard is not so much about super-high rig tensions, as some sort of consistent tension, without the rig rattling about...
I guess my situation was made worse by the jib halyard, P & S shrouds, and forestay all having cord "make-offs" to tension them; the cord for all this appeared to be still stretching when I got the boat. The shrouds/stay appear to be some sort of Dyneema, so that is perhaps why they settled, but the jib halyard had to go...
I don't use any 2:1 set up, as my BRe has a jib halyard winch (as I think most do?).
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Out on Rutland Water with Andy Dingle on Thursday (12 mph winds with gust of 16 mph) no reefs and empty tanks. We discussed windward performance of my BR20 GRP and Andy suggested we take a compass bearing on our current angle of attack and then on the other tack and see what the difference was to determine our pointing performance. I was disappointed with the result of 100 degrees, 90 would have been more acceptable to me, however we kept the boat speed up on both tacks and didn't try to improve the tacking angle by luffing up to much.
We filled the tanks and repeated the test under roughly the same conditions, a marginal improvement was achieved with the boat being flatter, and the conversation moved on to the weight of the water in the tanks and boat weight/reduction in speed, does the boat weigh more when afloat with the tanks full.
Be interesting to hear others results using this simple technique.
Peter C and Andy D
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Peter's last sentence reminds me of the old chestnut. A small boat, containing a heavy anchor, in a tank of water: the anchor is thrown overboard: does the water level in the tank rise or fall? [This has absolutely nothing (I think) to do with BRe windward performance.]
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Sorry, that should be 'last but one sentence'.
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We filled the tanks and repeated the test under roughly the same conditions, a marginal improvement was achieved with the boat being flatter, and the conversation moved on to the weight of the water in the tanks and boat weight/reduction in speed, does the boat weigh more when afloat with the tanks full.
As to the last question the answer is definitely "yes" and I can only remind people of my library article...
http://www.swallowyachtsassociation.org/?page_id=1183 !
I use Seatern's track on the chartplotter to determine tacking angle but, of course that only works in terms of boat performance if there is no current. In the latter case I think I can just about achieve 90 degrees OK but I'm not sure that gives me the best velocity made good, Seatern goes faster through the water if I free off say 3 degrees or so (which I can measure using the Tiller Pilot to steer). Whether the speed improvement is enough to improve my VMG I don't know but I suspect it is.
As to Michaels chestnut, a hint - in the boat the anchor displaces it's own weight of water. When the anchor is at the bottom of the tank it displaces it's own volume of water. The anchor is denser than water (assuming it sinks when thrown overboard!). I'll leave people to work out the rest!
Peter
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I suspect there must be an explanation somewhere on the forum but I can't find it. What part of the boat do I put my spirit level on to get the boat level so that I can then assess the mask rake?
Cheers to all,
Bob
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Bob
I pondered this one some years ago, if you have a smartphone you can use a clinometer app, you the hold the phone/iPad against the surface of the mast and it will display the upright angle for you. Hull level does not have to be considered with this method of measurement from my understanding.
https://www.youtube.com/watch?v=4mJh94Cm3zw
I guess you can prove the theory by taking the mast upright reading and then (assuming the boat is on the trailer) lowering/raising the jockey wheel to change the boat level and take the reading on the mast again.
Peter C
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Hi Peter,
Had a look at the app but not clear how that helps find/set mast rake. If my understanding is right (no guarantee there) then mast rake is relative to some "horizontal" part of the boat and this part of the boat needs to be set horizontal before one can use inclinometer?
Could you or others clarify?
Cheers
Bob
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Bob
“If my understanding is right (no guarantee there) then mast rake is relative to some "horizontal" part of the boat and this part of the boat needs to be set horizontal before one can use inclinometer?”
Bob, this is not my understanding, the app and device works independent of the boat horizontal plane position. Basically if the iPad for instance is held vertical the reading will be 0 degrees, if the iPad body is placed against the mast the reading will reflect the vertical upright degree of the mast.
As is said in the previous post if this is in doubt take the current mast reading and assuming the boat is on the trailer alter the boat horizontal position by adjusting the jockey wheel and take the mast reading again.
Peter C
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I'm like Bob T here, rake relative to what?
I think it is relative to the waterline as it floats. So have the boat in the water and use the inclinometer then to check mast not leaning forward.
If you are on the trailer you can make the inclinometer read whatever you like by adjusting the jockey wheel. That tells you nothing.
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If you have a waterline stripe painted on your boat and it’s accurate (mine is), you can use that, the inclinometer and the jockey wheel to get the boat absolutely level on your trailer. Then check mast rake as Peter suggests.
An alternative quick and dirty test of mast rake was mentioned by Ray S in this thread last month - attend a Swallow rally and compare yourself against other boats when rafted up. Even small variations in rake are fairly easy to spot and big variations really stand out.
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I checked mine on the water yesterday with the smartphone and it was exactly vertical. So some shroud tightening to come next week. I also had a Graham look along the berths and it is noticeable that a vertical mast is unusual, most are tipped back a little bit. I think mine has come more vertical since I put some effort into tightening jib halyard trying to get better on the wind. No affect I can feel on helm loading though, boat is beautifully balanced.
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Bob, this is not my understanding, the app and device works independent of the boat horizontal plane position. Basically if the iPad for instance is held vertical the reading will be 0 degrees, if the iPad body is placed against the mast the reading will reflect the vertical upright degree of the mast.
But as johnguy says, if the boat is not floating you need to know the angle of the hull to it's normal alignment when afloat. I use the table in the cabin (fixed to the top of the centreboard case) as an indication of the designed waterline since I assume matt would have intended that to be horizontal - and when afloat it is. So using the inclinometer built into the smart phone I measure both the rake of the mast and the slope of the table and hence work out the mast rake when afloat. Alternatively i just wait for the tide to come in!
Peter
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About the mast rake and what it is referenced to. I had a chat with Nick Peters, the Swallow technical director, at the boat show. He confirmed that the rake is relative to the waterline. So pop the boat in the oggin and pop an inclinometer on the mast. If you don't like the rake, you can adjust the shrouds or ask the mother in law to sit further aft. Nick also emphasised that in practice the rake makes very little if any difference. he says a bit of aft rake helps the boat look good in photos, but doesn't really affect sailing performance.
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Too rakish?
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Too rakish?
I had to full size the pic to see that the mast is on the RIGHT of the pic!
May seem daft, but my racing dinghy is factory fitted with a mast raking system, primarily so as to reduce weather helm, upwind in a strong blow. Hence increases speed too. It works....but its not a BRe....
Ever seen a Contender in full flight? Rig rake looks very similar..... ;D