Dinghy spinnaker: pros and cons of going asymmetric?

Greenheart

Greenheart

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As Fisherman Quint said, "Y'all know me, you know what I do..." :rolleyes:

I'm interested in what drives dinghies to perform better under particular points of sailing...and since my interest is theoretical at the moment, I'm not bothered about class rules, nor am I afraid of imagining systems which would invalidate a boat from racing.

I found an account of two Ospreys crossing the Channel, and one of them used an enormous asymmetric spinnaker...

"...at this point Richard and Steve produced their secret weapon, a huge masthead asymmetric! With their big spinnaker they were dramatically quicker than we were..."

I wish there'd been photos. Now, I realise that asymmetrics are no use at all, dead downwind. And I see that flying such a sail from the masthead would probably be restricted to light-airs work. And, it wouldn't make a versatile alternative to the Osprey's standard spinnaker...

...but for performance-addicted crews keen to get the most from specific conditions, is there any practical objection to having a whopping great kite on board, as well as the sensibly-proportioned, approved design?
 
Dan,

as you know I've sailed various performance dinghies.

When I got on a ' modern ' International 14 with an asymmetric kite, it was a revelation; so user friendly it was almost unbelievable !

True it wasn't brilliant dead downwind, but we tacked downwind at snorting high speeds to easily overcome that.

I did find gloves absolutley essential for the loads on the trendy thin low weight / windage sheets.

I have an asymmetric on my A22 now, and would love a carbon fibre bowsprit but it woud mean a piercing in the coachroof which I'm not prepared to do, or some sort of fold down sprit which I'm saving up for !

So a big + here for asymmetrics.
 
It's all about "the apparent".

Asymmetric kites are not really quicker overall than symmetric ones other than because you can fit more rag in the gap. They do make boat handling easier though.

The performance edge has got more to do with the ability to get a hull to plane, as then your apparent windspeed increases dramatically. So if you have a hull with a very biased polar, by sailing it at it's max vmg angle (which the kite will be cut for), you get the hull on the plane quickly. Then as the apparent wind increases and moves forwards, it bears you away, giving you a good vmg. However, they key is about keeping it planing.

On displacement dinghies which have a more even polar, and hence don't have a big planing "hump", an asymmetric will be slower around the course because it is not as flexible. This is why it's the lightweight boats (skiffs mainly) with easily-driven planing hulls with use them best.

Over the past 20-odd years, they have been shoved on lots of inappropriate boats by the manufacturers in an attempt to make their boats look cool and trendy, but then they tend to be one-design boats, so you'd never know if they were quicker with pole kites (which most would be).
 
Well my boat may be ' inappropriate ' but she goes like a rocket with an asymmetric, up to a close reach !

Also, these sails can be let fly in squalls which is important.
 
A conventional spinny doesn't let fly without massive drag as many have found to their cost.

As for the rest of your post, please explain !

- Edit to answer the latest smartarse, I've owned or sailed 1960's, 70's and 80''s Int 14's - the 1960's job was indeed a dog ! - but the thing I'm talking about was a late 1990's twin wire state of the art, carbon hull silly money exercise.
 
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Thanks Andy, all you say is welcome. I recognise what's also been said in support of conventional spinnakers, but for the type of large-ish, lightweight dinghy I'm planning to sail this year, I reckon an asymmetric isn't as loony a modification-plan as some of mine are...

...particularly as most bigger dinghies come with traditional spinnakers anyway. So adding an asymmetric masthead kite for conditions when it will spell the difference between planing and slacking, won't be a bad choice...more like an additional 'performance option'! I hope. :)

I suppose enthusiasts in established performance classes are so busy proving their skills with the standard equipment, that options like asymmetrics aren't felt to be relevant. Fun, though!
 
Seajet said:
A conventional spinny doesn't let fly without massive drag as many have found to their cost.

As for the rest of your post, please explain !

- Edit to answer the latest smartarse, I've owned or sailed 1960's, 70's and 80''s Int 14's - the 1960's job was indeed a dog ! - but the thing I'm talking about was a late 1990's twin wire state of the art, carbon hull silly money exercise.
Click to expand...

Yey, he bit!
 
Hi Dan,

the rig I'd really like to have is my current blade jib, along with a furler ( not reef ) asymmetric, snag is this has to be on a sprit.

I have tried my asymmetric on the spinnaker pole lashed to the foredeck but it's not ideal, one of the projects for this season ashore.

As for sailing some kind people have invited me for sails, including an Osprey; you're always welcome.

PS Int 14's of any vintage were always dogs compared to Ospreys !
 
You can let a conventional kite fly in a squall. It works perfectly. You just need to know which corner to let go...sheet the kite in hard and blow the halyard. It's called an Aussie Drop and works really well if you've gone too low for the next mark but need the kite for the next leg. Alternatively, give the kite a bigger than average curl, steer downwind, and just keep the boat under the rig. I don't think I've ever not been able to fly a Fireball kite on a dead run regardless of how hard it's blowing. Conversely you can't let an asymm flog on a skiffif you are in the groove...if you do, the world goes green very quickly and there's a mainsail on your head...

They did experiment in the 90s with asymm on a Fireball and by all accounts it was much faster. However, it was much bigger too, and would have destroyed the balls-out ('scuse the pun) nature of the class in high winds, plus the tactical racing in lighter winds.

Dan, you could do it, but as Bob eludes to there's not much point in putting an big asym on a boat unless it's fast enough to make use of it in the first place. Setup is everything...you need a proper, decent pole system and launching method...you really want one or the other, not both, or you will have compromises. But you could look at a system like the Alto has, which does enable you to angle the pole to windward so you can sail deeper...but personally, I'd rather run properly with a symm kite, or send it apparent wind sailing in a skiff.

Kite shape is important too...IMHO the 49er kite is far too flat, and it's very easy to "overwire" in lighter breeze, especially with chunkier crew. At the other end of the spectrum you have 12' skiffs which BobC and I raced, and you are even dialling in the right amount of heel downwind to counteract the lee helm...it really is a big bag of wind on he front of the boat (but a right laugh too!)

That said, I cut a length of old 18' skiff mast last night and I'm heading down to the boat this weekend to look at the foredeck of my Sabre and scratch my chin a lot and wonder how it's all going to fit. At just under a metre projection, it won't be a monster bowsprit, but I'm hoping that it should get the boatspeed up a bit downwind when I fit the new asymm. Still probably be quicker VMG wise with the proper kite, but the asymm will be easier to use short handed, and that's the general idea.
 
Searush said:
Have you bought your bloody boat yet, Dan? Get a move on son!
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Thanks Cap'n. I'll be afloat this spring, that I can say for certain...

...I'll promise this: if I can't supplement my threads with photos of my own boat by mid-May, I just won't post at all! ;)

Iain C said:
...you could look at a system like the Alto has, which does enable you to angle the pole to windward so you can sail deeper...it really is a big bag of wind on he front of the boat (but a right laugh too!)...

...I'm heading down to look at the foredeck of my Sabre...at just under a metre projection, it won't be a monster bowsprit, but I'm hoping it should get the boatspeed up a bit downwind when I fit the new asymm. Still probably be quicker VMG wise with the proper kite, but the asymm will be easier to use short handed...
Click to expand...

I had been thinking of the Alto, and there's some entertaining footage of an asymmetric-rigged 505, here:

 
Hmmm, kite doesn't look quite right to me...luff looks too tight, leach looks too open at the shoulders. TBH when the 5o5 went for the big kites back in the early 2000s they started sailing windward leeward courses anyway...so that American boat looks like a waste of a good five-oh!

But they look like they are enjoying themselves...
 
Iain C said:
...when the 5o5 went for the big kites back in the early 2000s they started sailing windward leeward courses anyway...
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So...maybe the most versatile answer would be to have a choice of conventional spinnakers - of differing sizes, including a vast masthead one?
 
dancrane said:
So...maybe the most versatile answer would be to have a choice of conventional spinnakers - of differing sizes, including a vast masthead one?
Click to expand...

Those of us who are actually experienced with conventional kites will know what it's like trying to fly them to spill wind...

Meanwhile

I do agree with the idea Dan should get on with it, musing about boats is a lovely pastime in itself but none of us are getting any younger and we might get hit by a meteorite or lorry any time...

Go on Dan, get something like a Foiler Moth or International Canoe and a rucksack then report back here about cruising the thing !
 
dancrane said:
So...maybe the most versatile answer would be to have a choice of conventional spinnakers - of differing sizes, including a vast masthead one?
Click to expand...

Yes, but watch the masthead idea. It's very easy to rip the top off the mast with no support. You can usually get away with about 18" above the hounds, but not much more without cap shrouds.
 
It is definitely time for you to buy a boat, Dan. I can only quote to you the wise words of Blondie Hasler in Practical Junk Rig, 'excessive preoccupation with theory is a sign of inexperience and a reason for not gaining more experience'.

As for cruising something like a Foiler Moth, I had a lovely sail yesterday shorthanded in a J80, and have been thinking ever since what fun it would be to chuck some minimal camping equipment into the tiny cabin and go off for a week on a boat that sails so beautifully, even if it wasn't designed as a cruiser.
 
I could lend you my conventional kite, 290 sq ft should give a bit of a boost to whatever dinghy you end up with !

Seriously, thinking about your cruising ideas Dan, how about a Kinsman ?

Not the sort of thing to pull up and down the slip on a trolley I'll grant you, but a tasty looking boat; a friend and I used to muse over the brochures as an abstract idea, now suddenly there are 2 at my club...

www.ykboats.co.uk/Ykboats.htm
 
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