Spinnaker 1.5oz

[mickshep]

I have been sailing some 30 yrs in a variety of older vessels, in all that time have never used a spinnaker, My latest vessel is a steel 32' masthead sloop, weighing in at about 6.5 tons, among her wardrobe of sails is a huge nearly new spinnaker of about 70m square mtrs. On the outside of it's bag which doubles as a chute to launch the blessed thing is stenciled 1.5oz which I guess is the weight of the cloth. It seems very very light to me and is I assume for very light airs, am I right in this? or are they a lot stronger than they look, what wind force would such a sail handle without risking damage to what is an almost unused sail, and without risking injury to a crew who have never used a kite before. Cheers and fair winds, Mike (Fosca Helena)

 

[charles_reed]

On the contrary, if it's 1.5oz US, it's a heavy spinnaker.

Usually light-air spinnakers are 0.75oz - my GP tri-radial which I use in up to 25 knots apparent is just that weight and about the same size as yours and my asymmetric is also 0.75.

One of the reasons that 1.5oz was used is that it is about 60% of the price of the lighter fabric.
Unfortunately it won't set in light winds.

 

[charles_reed]

On the contrary, if it's 1.5oz US, it's a heavy spinnaker.

Usually light-air spinnakers are 0.75oz - my GP tri-radial which I use in up to 25 knots apparent is just that weight and about the same size as yours and my asymmetric is also 0.75oz.

One of the reasons that 1.5oz was used is that it is about 60% of the price of the lighter fabric.
Unfortunately it won't set in light winds.

 

[charles_reed]

On the contrary, if it's 1.5oz US, it's a heavy spinnaker.

Usually light-air spinnakers are 0.75oz - my GP tri-radial which I use in up to 25 knots apparent is just that weight and about the same size as yours and my asymmetric is also 0.75oz.

One of the reasons that 1.5oz was used is that it is about 60% of the price of the lighter fabric.
Unfortunately it won't set in light winds.

 

[mickshep]

Thanks for that, just shows I wasn't joking when said knew nothing about them, Only thing I had to compare with were the normal working sails which are of course a lot heavier. Then the storm sails which are even more heavily made still.
Mike

 

[alan]

As Charles says 1.5 oz is quite heavy (for a spi). Here in the Med the racing boys use 0.5oz or 0.75oz. I have a 1.5 oz ginaker which is good for apparent winds up to 30 Knts on a run (or so the manufacturers say!!) - I haven't had the courage to keep it up in 30 Knts yet though !!!

You should be able to use your spi on a run in winds in up to 30 Knts apparent. Your 'normal' sails are likely to be around 7 ozs - so as you can see there is a lot of difference in sail weights. Try looking at the Bainbridge Sailcloth web site; they have lots of good info on sailcloth and weights e.t.c.

Good luck.

Alan.
Nettuno, Italy.

Alan Cloke

 

[Jacket]

Just remember that the boats steel and heavy, and so will respond more slowly to gusts, putting more strain on the sail. Therefore a 1.5 oz sail should probably only be flown in the sort of winds that a slightly lighter sail would be flown in on a racing boat.

 

[bedouin]

As others have said, 1.5oz is definitely on the heavy side. Even with my 0.75oz spinnaker the boat gets overpowered before the wind gets to strong for the sail. A 1.5oz sail could be carried up to at least 30 knots, but only racers would consider that.

I also have a 1.5oz spinnaker which I think is almost useless. As a cruising sailor I only fly the spinnaker in light winds in in those conditions the heavier spinnaker does not set well.

 

[Twister_Ken]

Clarification

Alan says...
>You should be able to use your spi on a run in winds in up to 30 Knts apparent.<

This might be a bit misleading!

a) As Mick has never flown a kite before, and they become a powerful sails with lots of ways of hurting yourself and the boat in a blow, I'd recommend it comes down when the wind gets to 15kts apparent (and even that might be a little brown trousers). I've flown small kites on racing boats at those sorts of windspeeds and it ain't relaxing. On one occasion, the spi halyard burst the sheave at the masthead, and the exit slot on the mast sawed through the halyard in seconds. When you suddenly sail over your spinnaker at 11 kts things get mighty interesting. That's when I learned the sense of not putting stopper knots in the sheet and guys.
b) at downwindpeeds above 15kts white sails are going to generate enough power to get a 6.5 ton steel boat (presumably with no pretensions at a planing hull-form) up to hull speed or very close to it, so there's no point in hanging on to a kite any longer, and
c) although the sail hasn't been flown much (if at all) before, it's still an old sail and might well have suffered some degradation in the sail bin, so why risk blowing it in strong winds.

I'm not much good with Sqms as opposed to Sqfts, but 70Sqm sounds like a very big sail for a 32 footer. Being 1.5 oz makes me suspect this just possibly might be a heavy weather kite off of a bigger boat. Does the sail number make sense?

 

[temptress]

Hi,

I do a lot of offshore RACING (when I have time) on a variety of boats large and small. I use the following as a rule of thumb:


0.5oz up to 12 knts apparent
0.75 from 10 to 35 knts app
1.5 over 30knts (the sail tends to 'blow out' when we get 45 knots or so)

You can use a 1.5 in any winds but when the wind is light (and this is when you can realy benefit from a spinnaker) the cloth will be just too heavy to set.

The weight of cloth should be matched to the wind not to the weight of the boat

Hope this helps.

Temptress of Down

 

[bedouin]

Re: Clarification

Thanks Ken, perhaps I didn't make myself clear.

My boat is also a heavy 32', and the big symmetric is about the size mentioned (67m I think) - conversion from ft to m is easy - just multiply by 10.

When cruising I regard 15knts apparent as pretty well the limit for flying the spinnaker and I don't usually hoist in more than about 12kts, simply because I don't need it - the marginal increase in speed is not worth the extra hassle.

At those sort of speeds, the lighter spinnaker is more than strong enough - which makes the heavier one almost useless. Even if I were a serious racer (which I'm not) I cannot imagine trying to fly that big a spinnaker above 20kts AWS.

There is no way I was intending to suggest that the spinnaker could reasonably be flown in 30kts - but just that if it could then the fabric would probably take it. In other words for cruising the strength of the fabric will not be the limiting factor.

 

[charles_reed]

Re: Clarification

I agree - the sail might be good for 30 knots but the rest of the gear, the crews' muscle-power and their nerve probably won't be up to those sorts of wind-speeds.

Anyway at 30 knots apparent I'd have to have put 2 reefs in the main and would be using the 150% genoa on the pole and getting a similar boatspeed to flying the spinnaker.

 

[aod]

hmmmmm...........I take issue with you on this.

This guy has a 32ft steel yacht which by definition will be a heavy beast. I am sure a 40ft racing machine flying a 1.5oz kite in 35knots true wind will be doing somewhere in the region of 15+ knots thus reducing the apparent wind to a manageable 20 knots.

You are talking about flying a .75oz kite in 35 knots apparent wind (which is what you said) the true wind speed will be somewhere in the upper 40s or maybe even the low 50s depending on the yacht.

Flying a 1.5oz kite up to 45 knots apparent wind affords you a true wind speed of some 60 knots and even the Volvos don't fly a kite in that because you can't get them down.

Contrary to what you said weight is an issue as is hull shape because if the boat cannot quickly accelerate in the gusts the apparent wind strength significantly increases and the kite, spin blocks and rig maxis out and something breaks.

Another factor is sea state because the yacht won't appreciate accelerating down a wave in a big wind and then plowing into the wave infront with a kite up.

I agree with a previous posting that in view of the vessel and the honest statement of inexperience 15 knots apparent is more than enough to cut your teeth on.

 

[mickshep]

Bloody hell!!!!!!!!!!
Thanks for all the help/advice, but as a purely cruising sailor with no kite experience am begining to wonder if huge kite that is too heavy for light winds might be a little more "brown trousers" than I like, anyone know how to turn a spinnaker into a continental frame tent????. Only joking! But when bring back boat to the North East does anyone fancy a play on an old steel Van De Stadt, (round bilge for the old fogies like me who remember when all boats were) with the intention off showing me how to use kite, Cheers, Mike

 

[aod]

Mick I would love to help you and I do teach race training which of course involves a deal of spinnaker stuff but unfortunately I attempt to earn a living through sailing and couldn't spare the time.
I am sure however that your post will receive a positive response from those who know what they are about and would be glad to go along for the crack.

I would point out that in order to use the said kite you will probably have to invest in some suitable ropes and blocks for the sheets, guys pole controls etc and you need to factor this in.

 

[mickshep]

Re: big scarey kites

Cheers for the support and all the advice,
It would seem all the gear is there for the kite, Will I think, brood on it for a bit, see what happens, plenty of things to do on the boat yet,
Regards Mike

 

[Jacket]

I'd be more than happy to help - I'm getting sailing withdrawl symptoms!

 

[jonjo]

Your spinnaker is about 10% larger and the same cloth weight as the Sigma 33 OOD (4.2 ton) heavy spinnaker.

I doubt it is going to be a useful sail and might not justify the storage space. It will be too heavy to set reliably in light winds, I assume your cruising chute will be the favoured broad reaching sail so that leaves the spinnaker for strong winds on a run.

> what wind force would such a sail handle

On a reach you will have water in the cockpit before the sail blows out.

> without risking injury to a crew

There is a steep learning curve with spinnakers. In two years I went from being too scared to launch it in 12 knots with a full crew to happily dropping 70m2 in 15 knots while single-handed.

 

[Twister_Ken]

Learning to fly a kite

One fun way to do this is to choose a day when the wind is light and is from the same direction as the current.

Anchor by the stern. lash the helm amidships, drop the other sails, then set the kite. By putting the helm over you can see how to trim it at varying windangles, can gybe it without too much hassle, etc. Good fun, and you'll get some odd looks.

 

[bedouin]

Give it a go

What I was trying to say is not that it is useless, but that the a heavy spinnaker like that is only usable in a restricted range of wind speeds.

From my own experiences with a similar boat/sail combination, I would recommend trying it out first when the wind is in the 10-12 kts true range - that should be about right to allow you to fly it without having any hairy moments.