Tomahawk
Well-Known Member
We always sail flat.
And fast..
10 kts is ptetty standard...
And fast..
10 kts is ptetty standard...
Sail flat, sail fast...
- Thread starter Greenheart
- Start date
Iain C
Well-Known Member
Dan
Dunno if you yet have SWMBO out on the trapeze, but until you match the ballast to the power, you are not really going to be able to compare your upwind performance to other boats in bigger breeze. Sailing a trapeze boat one up from a hiking position makes a HUGE difference. But if you have got to that point and want to know about the other stuff...
Prebend-this is the bend in the mast. Not rake...you can have a straight mast raked back a lot (Contender), this is bend. Controlled by the spreader angle, the more swept back the spreaders are, the more prebend you get, and the more the leach opens, spilling power. Again, a bit irrelevant with a reefed main or missing a crewmember, but I'll be surprised if you don't have some adjustment here.
Strut-as you wind the kicker on the mast will move forwards at gooseneck level. So normally, the mast needs holding steady somewhere between the deck and gooseneck to stop this. This can be a piece of rope or chocks around the mast, a ram/puller, or a strut. However, in extreme conditions, you can disable this system, allowing the rig to move forward at deck level and increasing prebend and dumping power.
Jib bars-in windy weather the main will be further off the centreline when fully powered so the jib needs to move out a bit to avoid choking the slot and back winding the main. Simply easing the sheet will lose the sail shape, so you move the last block that the sheet runs out (to move the jib out) and up (to open the top of the jib). Again many different systems for doing this...my fireball had spring loaded bars which would move both together in/out up/down on controls from the back of the cockpit, the FF simply has pinstop tracks that only go backwards/forwards and need to be adjusted manually by the crew.
Stuff-in a big gust, point up a bit. Keep the boat driving but point higher than you would normally. Head back down after the gust. Probably not going to work that well with a baggy reefed jib.
Enjoy
Dunno if you yet have SWMBO out on the trapeze, but until you match the ballast to the power, you are not really going to be able to compare your upwind performance to other boats in bigger breeze. Sailing a trapeze boat one up from a hiking position makes a HUGE difference. But if you have got to that point and want to know about the other stuff...
Prebend-this is the bend in the mast. Not rake...you can have a straight mast raked back a lot (Contender), this is bend. Controlled by the spreader angle, the more swept back the spreaders are, the more prebend you get, and the more the leach opens, spilling power. Again, a bit irrelevant with a reefed main or missing a crewmember, but I'll be surprised if you don't have some adjustment here.
Strut-as you wind the kicker on the mast will move forwards at gooseneck level. So normally, the mast needs holding steady somewhere between the deck and gooseneck to stop this. This can be a piece of rope or chocks around the mast, a ram/puller, or a strut. However, in extreme conditions, you can disable this system, allowing the rig to move forward at deck level and increasing prebend and dumping power.
Jib bars-in windy weather the main will be further off the centreline when fully powered so the jib needs to move out a bit to avoid choking the slot and back winding the main. Simply easing the sheet will lose the sail shape, so you move the last block that the sheet runs out (to move the jib out) and up (to open the top of the jib). Again many different systems for doing this...my fireball had spring loaded bars which would move both together in/out up/down on controls from the back of the cockpit, the FF simply has pinstop tracks that only go backwards/forwards and need to be adjusted manually by the crew.
Stuff-in a big gust, point up a bit. Keep the boat driving but point higher than you would normally. Head back down after the gust. Probably not going to work that well with a baggy reefed jib.
Enjoy
Tomahawk
Well-Known Member
Dan..
You haven't said what boat you are sailing. They all have certain tweeks....
You haven't said what boat you are sailing. They all have certain tweeks....
Iain C
Well-Known Member
It's an old Osprey, with some rather unconventional additions...
Tomahawk
Well-Known Member
From what I understand of an Osprey, they like to be upright…
The bow is sharp for cutting into the waves going uphill… the back is nice and flat for planing downhill..
It is a matter of tuning the rig to the wind when you go out.
If windy, flatten everything with bending the mast Etc
If calm allow more camber in the sails..
If you are being overpowered going uphill.. ease the main and allow it to luff … indeed almost until the battens are backwinding.
However do keep the leech reasonably tight..
The bow is sharp for cutting into the waves going uphill… the back is nice and flat for planing downhill..
It is a matter of tuning the rig to the wind when you go out.
If windy, flatten everything with bending the mast Etc
If calm allow more camber in the sails..
If you are being overpowered going uphill.. ease the main and allow it to luff … indeed almost until the battens are backwinding.
However do keep the leech reasonably tight..
JumbleDuck
Well-Known Member
Chuck Paine designed my boat (as I understand he designs all his boats) to sail best at an angle of 20 degrees. As I now realise, though, the OP's Osprey is a very different sort of hull and sailing.
Lakesailor
Well-Known Member
Another of the 17ft class rules is that they are not allowed to reef.
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Buck Turgidson
Well-Known Member
Looking at the previous pictures I hope there is no rule against bracing yourself foot on boom!
Lakesailor
Well-Known Member
Some of them don't seem to use the traveller
flaming
Well-Known Member
Upwind performance is about maximum righting moment combined with power available.
In dinghies this is normally when the boat is flat, or with minimal heel and the crew hiking / trapesing hard. As when you are flat it's possible to get the crew weight out furthest, and this normally has a greater effect than shifting the centre of buoyancy by heeling. Add in the effect of the weight of the rig pulling the boat over and it's clear that flat is best. In fact some classes (18 foot skiffs for example) are sailed upwind heeling to windward to enable them to use the weight of the rig to aid righting moment - plus gain lift from the sails.
In yachts this comes at various angles depending on the size / weight of keel and the shape of the hull. Put simplistically the more a yacht heels the closer the keel is to its max effectiveness (90 degrees) and the more the effect of the leeward side of the hull being submerged and so the centre of buoyancy shifting away from the centreline. At the same time the power of the sails decreases as the boat heels, so at some point the two graphs cross and you have your optimum heel.
In dinghies this is normally when the boat is flat, or with minimal heel and the crew hiking / trapesing hard. As when you are flat it's possible to get the crew weight out furthest, and this normally has a greater effect than shifting the centre of buoyancy by heeling. Add in the effect of the weight of the rig pulling the boat over and it's clear that flat is best. In fact some classes (18 foot skiffs for example) are sailed upwind heeling to windward to enable them to use the weight of the rig to aid righting moment - plus gain lift from the sails.
In yachts this comes at various angles depending on the size / weight of keel and the shape of the hull. Put simplistically the more a yacht heels the closer the keel is to its max effectiveness (90 degrees) and the more the effect of the leeward side of the hull being submerged and so the centre of buoyancy shifting away from the centreline. At the same time the power of the sails decreases as the boat heels, so at some point the two graphs cross and you have your optimum heel.
Greenheart
Well-Known Member
All very encouraging, cheers. I'm in the process of acquiring a decent trapeze harness - for myself, not SWMBO - and I realise the increase in righting force will increase a lot once I've mastered it. Thanks for explaining your tweaking methods Iain.
I reckon my old Osprey was very far from the sophisticated modern version even before I bought her, and as you say I've made peculiar modifications, not performance-minded.
I can see good sense in having a system that allows the jib to be sheeted in hard whilst opening its angle. But I doubt my foredeck is stiff enough to support a mast-strut. Although, singlehanding, I doubt I'll want to go out when there's enough wind to need such bracing of the mast. As to changing spreader-angle or length...I found some damage to the spreader-base this month - a rivet has popped out and the spreaders are no longer their symmetrical angle...
View attachment 39165
...I'll be content just to have them back approximately as they were. D'you think I should grind off the other rivets then use a vice to 'bend' them into symmetry?
The boat is just as tatty and elderly as it appears, so I'm not trying to tune it for handicap-busting performance, just hoping to use all skills & cheating methods to keep her flat.
I reckon my old Osprey was very far from the sophisticated modern version even before I bought her, and as you say I've made peculiar modifications, not performance-minded.
I can see good sense in having a system that allows the jib to be sheeted in hard whilst opening its angle. But I doubt my foredeck is stiff enough to support a mast-strut. Although, singlehanding, I doubt I'll want to go out when there's enough wind to need such bracing of the mast. As to changing spreader-angle or length...I found some damage to the spreader-base this month - a rivet has popped out and the spreaders are no longer their symmetrical angle...
View attachment 39165
...I'll be content just to have them back approximately as they were. D'you think I should grind off the other rivets then use a vice to 'bend' them into symmetry?
The boat is just as tatty and elderly as it appears, so I'm not trying to tune it for handicap-busting performance, just hoping to use all skills & cheating methods to keep her flat.
mrming
Well-Known Member
There's a factor missing here. The keel is also a foil, providing lift to windward and reducing leeway. Heeling reduces the effectiveness of the foil. If the keel is at 90 degrees the boat is going sideways. That's why canting keel boats have daggerboards. Some yacht designs with overhangs are faster heeled as their waterline length increases (the trade off with leeway is worth it), but other than that flat is generally fast except in light airs when it often pays to induce a bit of leeward heel to reduce wetted area and encourage the sails to fall into shape (as others have already said).
Kelpie
Well-Known Member
I'd be surprised if you needed to do anything more than bend them back by hand. The steel will be very thin. But it might be prudent to replace all the rivets if some have already failed. Might be easier to drill them out, and make sure you use monel replacements, and slather on some duralac between the al and the other metals.
Sailfree
Well-Known Member
If you really want to sail faster in a heavy dinghy like a Wayfarer we luff up at the top of waves and bear away going down them the essential think is to keep boat speed.
Always look to windward and anticipate gusts. Let sails out to keep boat flat when gust hits then bear away down the gust holding it for as long as possible then with extra boat speed pull sails in as wind will go more to front. Use boat speed at end of gust to point higher. Up in the lulls bear away in the gusts when reaching. But NEVER at the expense of boat speed.
Mike Mac who at various times has been World Champion in various Dinghy classes describes it a "flobbling" the tiller to keep boat speed but ease up to point high without loosing boat speed.
The beat is what sorts sailors out and spreads the fleet here its opposite when a gust hits the apparent wind goes back and gives you a lift so you luff up in a gust when beating.
Other points of sailing apart from sail trim is the lateral position of the boat. In a Wayfarer we want the bottom of the transom to just be touching the water and we often have to start with both Helm & Crew weight forward then slowly get back as boat planes. Number of times you see the transom buried before achieving speed and a slow boat.
There are lots of good RYA books but sailing with a number of your own class is best. Clear wind is also essential and you get disturbed air often up to 14 boat lengths downwind of another boat.
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Iain C
Well-Known Member
We are talking about sailing upwind here. Much of what you have said, I would totally disagree with. Whilst I do sail boats at the opposite end of the performance spectrum to a Wayfarer (Moth, 49er), much of it is equally applicable to a fast conventional dinghy like a Fireball (sailed one for 13 years) or an Osprey like the OP's. I am also talking about fully powered up, upwind, ignoring waves, in a "we-really-need-to-lose-some-power scenario".
The OP is asking how to keep the boat flat as he gets overpowered when others are not. We've already established he is sailing without a crew so looking for clear air isn't really relevant!
Sorry to come back a bit harsh, but bearing away going upwind in a gust in an overpowered Osprey is just plain wrong and will just end up in a boom-hits-water, boat heels, rudder stalls, high speed swim. Dan, don't do it.
Be ready for it by all means, but easy the sails as the gust hits, not before. You'll lose speed and pointing, and when the gust arrives it will seem harsher if the boat's not already in the groove.
Why? Just when you are trying to dump power you are bearing away and powering the boat up. You are also loosing height. You bear away going downwind, not upwind!
So how does that work then? Increased boat speed = apparent wind moving forward. When the apparent wind moves forward, you have to bear away to compensate otherwise your sails start to stall because you are now pointing too high. This may not be that obvious in a Wayfarer, but trust me in a 49er it's very obvious indeed.
Nope. Going upwind, other way around. Going up in a lull dumps your crew in the water. Especially true for a twin wire skiff, but also very applicable to a single wire boat with the crew flat wiring.
Sounds a bit like my "keep the boat driving but point higher than you would normally" technique...
The OP is asking how to keep the boat flat as he gets overpowered when others are not. We've already established he is sailing without a crew so looking for clear air isn't really relevant!
Sorry to come back a bit harsh, but bearing away going upwind in a gust in an overpowered Osprey is just plain wrong and will just end up in a boom-hits-water, boat heels, rudder stalls, high speed swim. Dan, don't do it.
lw395
Well-Known Member
Some of them don't seem to use the traveller
That one needs to ease the kicker, as easing the traveller won't help with the boom in the water.
lw395
Well-Known Member
In a dinghy like an Osprey, maximum righting moment will be with some significant heel, due to the buoyancy of the leeward side of the hull, i.e. form stability.
But it is still generally faster to keep it as flat as possible.
Generally a heeled dinghy is trying to turn and the rudder is fighting that causing lots of drag.
Greenheart
Well-Known Member
Thanks to all once again, for this advice.
Rob, how critical are monel rivets? I just spent £12 on an assortment of 700...no idea what they're made of though. Duralac? Does it discourage the inferior metal from disintegrating?
Regarding Iain & Sailfree's alternative points of view, I reckon it does relate to the type of boat sailed, and the type of sailing too...
...until last year in the Osprey, I'd never experienced the unhappy moment when you realise that if the boom hits the water, it'll be too late to prevent capsize. All the junior/novice boats seem to have been designed so that dumping the mainsail gets you out of trouble almost till she's on her ear...
...but in a light breeze last July, nudging force 3, the Osp heeled suddenly; for a few seconds the boom was about 9" from the water; I luffed hard and prayed, and slowly she came upright. In other classes I'd never had that unpleasant feeling that I couldn't release the mainsheet because something else would hold it in. Maybe it's related to boom-height.
I can totally see that everything which makes controlling the boat easy when it's upright, is decreasingly effective the more she heels.
I sailed down Chichester Harbour under reefed sail in a Mirror in the 'eighties, from Bosham to East Head, barely keeping control. An old boy in a Guernsey sweater was singlehanding a Flying Dutchman with full main, on the same route. He didn't use the genoa and I daresay he had the kicker bar-tight, but he didn't heel at all, just made steady, controlled pace all the way. He didn't use the trapeze. He didn't even have a buoyancy aid, crazy old coot. Pretty cool though.
Rob, how critical are monel rivets? I just spent £12 on an assortment of 700...no idea what they're made of though. Duralac? Does it discourage the inferior metal from disintegrating?
Regarding Iain & Sailfree's alternative points of view, I reckon it does relate to the type of boat sailed, and the type of sailing too...
...until last year in the Osprey, I'd never experienced the unhappy moment when you realise that if the boom hits the water, it'll be too late to prevent capsize. All the junior/novice boats seem to have been designed so that dumping the mainsail gets you out of trouble almost till she's on her ear...
...but in a light breeze last July, nudging force 3, the Osp heeled suddenly; for a few seconds the boom was about 9" from the water; I luffed hard and prayed, and slowly she came upright. In other classes I'd never had that unpleasant feeling that I couldn't release the mainsheet because something else would hold it in. Maybe it's related to boom-height.
I can totally see that everything which makes controlling the boat easy when it's upright, is decreasingly effective the more she heels.
I sailed down Chichester Harbour under reefed sail in a Mirror in the 'eighties, from Bosham to East Head, barely keeping control. An old boy in a Guernsey sweater was singlehanding a Flying Dutchman with full main, on the same route. He didn't use the genoa and I daresay he had the kicker bar-tight, but he didn't heel at all, just made steady, controlled pace all the way. He didn't use the trapeze. He didn't even have a buoyancy aid, crazy old coot. Pretty cool though.
Iain C
Well-Known Member
Monel rivets are IMHO essential. They will probably be over £1 each, but it depends if you want to risk breaking your mast over the failure of a fiver's worth of rivets!
Greenheart
Well-Known Member
Jeepers. Thanks. Any particular source for them? It's not the money, it's the difficulty of finding them.
EDIT: use internet, dumbo. Loads of outlets. Cheers.
EDIT: use internet, dumbo. Loads of outlets. Cheers.