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Death Roll and how to avoid it...? |
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RS400atC
Really should get out more Joined: 04 Dec 08 Online Status: Offline Posts: 3011 |
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Topic: Death Roll and how to avoid it...? Posted: 21 Jun 12 at 10:24am |
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That's why most modern boats have chines. Is the EPS one of the 'we don't need to design for ply wood' era, all rounded? In my varied but selective experience, rolling is fiirstly caused by the top of the main driving the mast to windward. It is kept in check by: Kicker Steering Sheeting in and heading up a bit. Possibly heeling to windward a bit, rig centre over hull. I say kept in check rather than stopped, because in some boats, rolling a bit or being on the edge of it is not slow. The real cure is to get the kite up, speed up, get the apparent wind off the stern. |
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Rupert
Really should get out more Joined: 11 Aug 04 Location: Whitefriars sc Online Status: Offline Posts: 8956 |
Post Options Quote Reply Posted: 21 Jun 12 at 12:11pm | |
Before Lasers started doing it so well, this was called the "Firefly Death Roll", and once it started, the helm would be screaming at the crew (me) to sit still. The answer in a boat with shrouds was always to sheet in and drop the centre plate a bit, but with a shroudless rig like the EPS, bearing away to rebalance the boat certainly works, as the rig can go so much further forward.
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Firefly 2324, Puffin 229, Minisail 3446 Mirror 70686
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G.R.F.
Really should get out more Joined: 10 Aug 08 Location: United Kingdom Online Status: Offline Posts: 4028 |
Post Options Quote Reply Posted: 21 Jun 12 at 12:16pm | |
Yes it has an edge to edge curve as well as a nose to tail parabolic rocker with what looks quite close to a shift to flat that we use windsurfing, sailed flat it really is as 'quiet' a wake as you could wish for, it doesn't like to be on its ear and all that rocking is not good news. The obvious answer is never dead run but then on a lake with a short buoy to buoy course, comes the time you have to point right at them and should that coincide with a shift..... You don't get death rolls with kites, well not that I've ever experienced it seems to be the province of certain single handers, I bet that 300 would get five stars if ever death rolling were in the michelin catalogue.
Edited by G.R.F. - 21 Jun 12 at 12:17pm |
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pondmonkey
Really should get out more Joined: 12 Aug 11 Online Status: Offline Posts: 2202 |
Post Options Quote Reply Posted: 21 Jun 12 at 12:25pm | |
4.5... the reverse flare gives some crucial face saving opportunity... if you're alert (or have exceptional fitness )
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maxibuddah
Really should get out more Joined: 06 Mar 09 Location: United Kingdom Online Status: Offline Posts: 1760 |
Post Options Quote Reply Posted: 21 Jun 12 at 12:42pm | |
never really used to death roll the 300. the hull accelerated as quickly as the rig meaning the generated lift on the sail didn't happen so much. of course if it got a little on the draughty side of things you could just move aft and dig both wings in to act as stabilisers, again slow but safe. the wings stopped an awful lot of rolling if needed.
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Everything I say is my opinion, honest
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RS400atC
Really should get out more Joined: 04 Dec 08 Online Status: Offline Posts: 3011 |
Post Options Quote Reply Posted: 21 Jun 12 at 2:12pm | |
I've seen a keelboat roll with the kite up, to the point where it filled up and sank. So a kite is not a total cure. But a dinghy with a kite would have been going much faster, got the apparent forward etc. Enterprises were always known for rolling, less chines that say a GP and no kite, and in the days I sailed them, mickey mouse kickers. The 400 is certainly much happier with the kite up, at least until it's time to gybe. |
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G.R.F.
Really should get out more Joined: 10 Aug 08 Location: United Kingdom Online Status: Offline Posts: 4028 |
Post Options Quote Reply Posted: 21 Jun 12 at 4:25pm | |
It probably only has been in my case since I've only ever experienced assyms that are loaded to one side come what may. It also occurred to me, the longer and lower the boom the more likely it must be, although I've not seen boats like Contenders engage in the habit, then they have flatter hulls.
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pondmonkey
Really should get out more Joined: 12 Aug 11 Online Status: Offline Posts: 2202 |
Post Options Quote Reply Posted: 21 Jun 12 at 4:36pm | |
how many contender sailors would run2run gybe? I'd have thought it was be tippy as hell with the relatively high aspect rig, low freeboard and narrowish beam???
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fab100
Really should get out more Joined: 15 Mar 11 Online Status: Offline Posts: 1005 |
Post Options Quote Reply Posted: 21 Jun 12 at 5:29pm | |
You could always just spray the mast-top with WD40, GRF. It repels water after all, so the effect should get stronger, the more the boat heels
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Steve411
Really should get out more Joined: 09 Sep 08 Location: Cheddar, Somerset, England Online Status: Offline Posts: 705 |
Post Options Quote Reply Posted: 21 Jun 12 at 6:11pm | |
The 300 may occasionally heel a bit to windward on a run in a blow, but so will any boat sailed incorrectly - the 300 just tells you quicker than most boats.
As Sargesail mentioned, there is more than one way to get downwind safely. I love this picture as it's all there - http://www.chunkypics.co.uk/photoalbum/Sport/Sailing/2007/RS300%20Inland%20Champs%2001-12-07%20NSC/Saturday/Page%202/E5013673.jpg
Sargesail is in 506 - bit of kicker, boom well out, rock steady. I'm in 411, bit less kicker, boom in a bit more, rock steady. The thing in commom is that both of us have the top batten in line with the mast. Letting the top batten go in front of the mast is what causes death rolls - http://www.chunkypics.co.uk/photoalbum/Sport/Sailing/2007/RS300%20Inland%20Champs%2001-12-07%20NSC/Saturday/Page%202/E5013590.jpg
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