Reefing a 505? Am I dreaming?

[Greenheart]

By degrees, I was gradually appreciating that so tunable are top-flight racing dinghies like the 505, that even in strong winds, a few adjustments to the shape of the sail allow it to spill enough wind not to be overpowering...hence, reducing the sail's size isn't necessary...

...but a bit of a scan on the internet found this page, from the US: http://www.usa505.org/tips/heavy-air-falsone

...and please, no howls to the effect of 'the Americans would do that, wouldn't they?'...the writer seems sincere...

...but there, in the fourth paragraph, amid dimensions relating to mast-rake, is the following line:

...we might be back at 25’0” in a steady 18 knots of wind. As it gets up over 22, we might be back at 24’9 or further. The first reef goes in at 25’2”, especially if there are waves...


The first reef? Am I to understand that these guys actually routinely take in a dozen or so square feet of the main, or more, to ease the lunacy in fresh to strong winds? Not that I'm not glad to hear it - it just wasn't what I'd been led to expect.

 

[Seajet]

Dan,

for your cruising purposes I think reefing or a smaller main will be necessary, not just detuning the main; it's all very well fitting a topping lift and scandalising, but downwind in a blow will still be a handful and scandalising with the kicker off risks a chinese gybe, life might become too interesting or expensive !

Never heard of reefing such boats when racing, I thought 'death or glory' was the normal racing technique...

 

[Keen_Ed]

It's a small flattening reef, mainly designed to lift the boom to give the helm enough room to get underneath.

 

[Seajet]

Ah, that makes sense, thanks.

 

[Neil_Y]

Back at 25'00" ? what on earth is he referring to? he seems to just be talking about rake, could this be the measured distance from mast/main halyard top to transom? seems about right.

As Keen Ed has shown many of these older classes have flattener reefs, but you normally go for a flat sail with cunningham and mast bend as well and add rake if you can. my 14 doesn't have a flattener but we can rake the rig back on the water which makes a huge difference. Cruising a 505 isn't too much of a handful just gybing with the symetric kite and that long boom can be interesting in 20knts. I used to crew one years ago at Portishead steep waves muddy water and high speed groundings come to mind.

 

[Keen_Ed]

masthead to the bottom of the transom, iirc.

 

[TSB240]

Raking rigs and flattenners were introduced to quite a few classes in the the late 70s and early 80s

My experience was with their introduction in the Scorpion class.

There was a simple quadrant lever system developed by the 79 champion only to be rapidly replaced by an expensive hydraulic set up used by Mike Lennon in 1985, 86 and 87.

This was subsequently banned by the class but they continue to this day with wire and pulley systems that allow the rig to be dramatically raked in windy conditions whilst sailing.

Raking the rig and effective use of the cunningham and flattener had a huge effect on depowering the rig so that it was much more manageable in heavier conditions.
It then became the norm for all crews to keep the boat flat and plane to windward in conditions which would have normally meant being wiped out.(Unless you employed the services of a honey monster crew)

Keeping the boat flat also meant playing the mainsheet. The flattener allowed the boom to not only clear the rear side decks but also to avoid catching waves and the inevitable ditching.

IMHO a minor benefit was being able to get under the boom......

 

[Greenheart]

Thank you gentlemen, that's very clear. It hadn't occurred to me the 'reef' might be to give space under the boom...I understand Contender crews do the same thing for extreme rake situations, actually permanently shortening the luff to enable underboom movement.

I have to say, a system that rakes the rig, flattens the sail and allows the boat to stay upright, planing to windward in conditions which normally led to overpowering, sounds fantastic - why would it have been banned?

My queries are always non-racing related, so I'd consider any system that tames the powerful sailplan in strong winds, as I'm unaffected by rules; unless of course it was banned because it led to chronic over-stressing of the rig, breakages, something like that?

Thanks for your input.

 

[sailor211]

I have a flatner on my yacht main. Takes 200 mm out at the back, and flattens the main quite a lot. First part of depowering when a first reef would be to much.

 

[Greenheart]

Please forgive me if I return to entry-level understanding...and then go a few steps even further back...

...is the raking of the mast, simply the consequence of extreme sail-control tension, as a means to flatten the sail?

I had thought that rake was a matter of moving the centre of effort astern a few inches, to balance the slightly retracted centreboard, which had thereby moved the CLR astern.

I can accept that the sail must be flat as possible in a hard wind, but I'm not clear how or why raking the mast helps that.

 

[rwoofer]

Please forgive me if I return to entry-level understanding...and then go a few steps even further back...

...is the raking of the mast, simply the consequence of extreme sail-control tension, as a means to flatten the sail?

I had thought that rake was a matter of moving the centre of effort astern a few inches, to balance the slightly retracted centreboard, which had thereby moved the CLR astern.

I can accept that the sail must be flat as possible in a hard wind, but I'm not clear how or why raking the mast helps that.

Generally raking reduces lift a little(less of a leading edge in the vertical plane), lowers CoE (therefore less righting moment needed), opens the slot a little (less drag) and allows you to pull up some centreboard whilst maintaining balance (which gives you more leeway, effectively taking power away from the sails).

On many boats rake also allows more mast bend. For example on my Phantom it has fixed lowers, so when you put the kicker on the mast bends until the lowers are taught. By raking the mast, more bend can be applied before the lowers are taught. This means that mast rake with extra kicker is the most important depowering control and the cunningham is only put on after that.

 

[[23929]]

Generally raking reduces lift a little(less of a leading edge in the vertical plane), lowers CoE (therefore less righting moment needed), opens the slot a little (less drag) and allows you to pull up some centreboard whilst maintaining balance (which gives you more leeway, effectively taking power away from the sails).

Dinghies with dagger boards pretty much don't bother with raking when the wind increases. They just rag off the top of the mainsail (cunningham/kicker on hard) to lower the CoE and pull the dagger board up since far less area is needed, to maintain lift, as the boat speed is faster. Now the CoE of the rig and the dagger board are closer to the hull and the boat is easier to sail.

Boats with pivoting centreboards, ie a 505 can only reduce the effective depth of the board, as the boat speed increases, by pivoting it backwards. This shifts the boars CoE back at lot ! Therefore, the rig needs to be raked back to compensate. If the top of the mainsail is ragged off as well, the CoE of the mainsail is very effectively lowered toward the hull.

The other consequence of raking the mast back is that it allows the jib leach to twist off, again lowering the CoE of the jib, which is a big help on boats with big jibs.

Here is a photo of a slow dinghy, sailing to windward in what was a pretty windy race. The board is raked back, the mast is back, the mainsail is only a third filled and two thirds ragged off and half the jib is ragged off. The boat is nice a stable, not bucking in the gusts, upright and going at hull speed.

When it gets mentally windy, there is no choice other than to reef as even the ragged off main will capsize the dinghy.

Here is a 505 with Firefly sails.

 

[Greenheart]

Thanks for those posts, very instructive. Fabulous photos too - that 505 crew look like it's a day they'll never forget!

By "ragged off", I infer that you mean the sail is twisted out of its normal shape so that even when the mainsheet is hauled in tight, large sections at the top of it will be free, spilling wind? Hence the drive comes from lower down, which is easier to correct...?

Believe me, I'm taking this all on board, and I think I'm understanding it; although it's still a little hard to believe, that when "ragging off" is necessary, it wouldn't be better simply to hoist a significantly smaller mainsail than the standard one...

...I realise a smaller main will have a lower head, so the mast won't bend to spill wind in gusts; but at the stage where the mast is raked back and most of the top of the main is deliberately made redundant to reduce heel, wouldn't a smaller sail have had the same effect?

The 505 with Firefly sails and three modestly-proportioned crew on the sidedeck...that's interesting on various points...

...what I wonder was the wind strength, that day? It looks like the wrong side of 35 knots!

How well had the 505 performed with non-standard sails, to lead this crew to resort to them on this occasion? I'm guessing they're okay - not perfect, but much better than overwhelming thrust hitting the 505's standard area harder than any technique can cope with?

...and...nobody's on the trapeze! Sense of self-preservation, I guess?

 

[[23929]]

Thanks for those posts, very instructive. Fabulous photos too - that 505 crew look like it's a day they'll never forget!

By "ragged off", I infer that you mean the sail is twisted out of its normal shape so that even when the mainsheet is hauled in tight, large sections at the top of it will be free, spilling wind? Hence the drive comes from lower down, which is easier to correct...?

Believe me, I'm taking this all on board, and I think I'm understanding it; although it's still a little hard to believe, that when "ragging off" is necessary, it wouldn't be better simply to hoist a significantly smaller mainsail than the standard one...

...I realise a smaller main will have a lower head, so the mast won't bend to spill wind in gusts; but at the stage where the mast is raked back and most of the top of the main is deliberately made redundant to reduce heel, wouldn't a smaller sail have had the same effect?

The 505 with Firefly sails and three modestly-proportioned crew on the sidedeck...that's interesting on various points...

...what I wonder was the wind strength, that day? It looks like the wrong side of 35 knots!

How well had the 505 performed with non-standard sails, to lead this crew to resort to them on this occasion? I'm guessing they're okay - not perfect, but much better than overwhelming thrust hitting the 505's standard area harder than any technique can cope with?

...and...nobody's on the trapeze! Sense of self-preservation, I guess?

When it's windy close hauled, the boom will be off the centreline, hence the jib needs twisting off. You want to get the boat planing and this requires loads of drive from the rig without too much heeling force. Hence, getting the drive low down is vital. Ragging off the top of the mainsail is spilling the wind from the top and the sail just flows like a flag, minimising drag. See the Lark dinghy photo.

You also need to pull up the board - think of it as reefing the board. At a higher speed it will provide enough lift but have less drag. Dagger boards are particularly efficient at this as they not only reduce the board area in the water but maintain the CoE position.

It is a good idea to reduce the sail area if it is windy and 18 Foot Skiffs as well as other performance boats and windsurfers do it. But with a 505 you want all the sail area for the downwind legs. You will be a bit stuffed with a diddy mainsail on a run, even though you can put up a kite.

I wouldn't worry about altering mast bend. Just set it up for the mainsail luff curve and forget about it. The bit of mast above the hounds will bend off just fine automatically especially when you pull on the cunningham.

505s are pretty technical boats with a lot of string. My view is to set it up about right and just concentrate on a couple of key controls like the kicker and cunningham. Then get the boat going as fast as you can and keep it in the groove.

 

[Greenheart]

Thanks again, for that. Good points about the centreboard & where the drive is coming from and how it converts to usable thrust. I'd forgotten about keeping the mainsheet traveller well off-centre in high winds, to encourage forward drive rather than high pointing.

My non-racing style of sailing means that when things edge towards the extreme, I'll be happy throttling back by any means possible. If that means things are a bit pedestrian downwind, I doubt I'll be complaining...so perhaps, a smaller suit of well-fitting sails for F5+...

Footage here of an Osprey wearing Scorpion sails, holding up quite well in a serious breeze:

http://www.youtube.com/watch?v=Tf9qS8_0GN0

In case you hadn't realised, I don't have a dinghy at the moment; this thread is part of my in-depth nineteen-year project to discover the best sailing dinghy, without actually sailing any. I've lots of earlier experience, but not much in recent years...

Cheers.

 

[lw395]

......

Here is a 505 with Firefly sails.

You'll note that this popular photo dates from the era of cotton sails!
Has anyone been photographed with small sails on a 5-oh this century?

I've heard several explanations of why more rake makes a boat faster upwind in stronger winds, I'm not convinced that any of the explanations is the full story, but it definitely works on most boats. Some things you just have to accept and make use of without total understanding.

 

[rwoofer]

I wouldn't worry about altering mast bend. Just set it up for the mainsail luff curve and forget about it. The bit of mast above the hounds will bend off just fine automatically especially when you pull on the cunningham.

I think we share a similar understanding however I would not state this bit. When the top is twisted off and you are overpowered, you still want the sail flat low down. The kicker and the outhaul mostly control that and I would definitely advise using them to get more bend low down. Perhaps you were just trying to simplify, which is fair enough.

As you say, above the hounds the leech tension bends the mast and also helped by the cunningham.

LW395 - it reallys depend on each boat as to the relative impact of all these aspects. For example some boats really don't like the cunningham as it makes the sail very twitchy (CoE wanders about too much). When you've got backstays then you'll be using that more anyway.

 

[Greenheart]

...some boats really don't like the cunningham as it makes the sail very twitchy (CoE wanders about too much). When you've got backstays then you'll be using that more anyway.

Hmm...all very interesting, so I'm sorry to trip up the flow of thought...

...but as I'm only thinking of dinghies, are backstays relevant? I'm shocked to admit I don't know...I thought dinghies were given shrouds, and that shroud tension was decided before the days' sailing starts, (or possibly before the season starts ) and left that way!

 

[rwoofer]

I was straying into yacht territory there. Don't actual know of a dinghy with a backstay, but that is not say one doesn't exist.

My albacore shrouds and forestay can be adjusted as you are sailing. The shrouds even have separate fine and course tuning. Generally rig raked forward downwind and back upwind.

 

[Wansworth]

Many years ago my bruz and I borrowed a Fireball from our club at Lttlehampton.T.C.A.L.S.SHORT we ended up down tide with a rising wind so I reefed the main and we managed to make our way tacking into the river.On arrival we where accosted by the class captain, who weighed both our weight together,that WE dont reef Fireballs!!!My fathers baot which we sailed was old school dayboat so we where basically ostracized from the club.....