After reading the post on I-17 sailor needing advice on pointing, I came to the realisation that I should ask you guys about sailing with a Spinnaker, since it is a new thing to me (on a cat, anyway.)
I sail a Mosquito 16ft cat, similar to your class although a bit underpowered in comparison - 100kg boat weight, 12,5sqm main, 3,5sqm jib, 16sqm spinnaker (the spinn. is an add-on - not std in the class.)
A few questions I have are as follows :
- Under spinnaker, trying to head up onto a beam reach, the boat suffers from excessive lee-helm. Bearing off helps alleviate this, but at times it may be necessary to sail high. like in a distance race where
there may be a long beam reach. (Mast is plumb, if I rake back I get weatherhelm upwind.)
- As the wind increases I find the need to bear off even more - a factor no doubt due to apparent wind moving forward making you bear off.
- I have been keeping the traveller close on centred, mainsheet in fairly tight, even in 5-8knots, as the gusts come I bear off, as they die I head up. Even in this wind range I find the highest I can "point" seems
to be a broad reach. In under 5knots I can head up higher. At this point crew is on leeward hull, I`m sitting forward & inboard trying to raise windward hull. Head up in lulls, bear off in gusts.
As the breeze increases I move weight back & outboard, eventually getting crew on the wire in 12 knots plus.
Centerboards are always half-down.

My question is : Does this sound like the right technique to sail with a spinnaker in these wind ranges ? What do I do as the wind gets up above 15 knots ? Are there any "newer" techniques to sailing fast with a
spinnaker ?
Anyone with valid go-fast info, please let me know.
The learning curve just got steeper.

Steve

Steve,

I've never sailed with a spinnaker so can't give you advice on your problem.

I would imagine however that once the wind got to 15knots it would be time to drop the spi for a beam reach. The boat would pretty much be at hull speed by this stage and the spi probably won't get you to go any faster wheres the risk of disaster would be quite high.

As I say I haven't sailed with a spi so may be completely wrong.

Can the Mozzie mast handle the spi OK?

Rob.

Hi Rob,

Thanks for reply - as you say, I don`t intend to beam reach with spinn. in 15 knots, as the wind increases you get pushed down by your apparent wind.
If you haven`t sailed with a spinnaker, good idea to try it, you will become addicted fairly quickly. Ask me !
Regarding the Mosquito mast holding up, as long as you sheet the main in fairly hard you stiffen the mast up with the mainsail leech, sort of like a backstay
which supports the mast. I`m speaking for the South African Mosquito masts, not sure if the Aussie masts are stiffer/stronger than ours. I know that one of the
Aussie Moz sailors has also experimented with a spinn, not sure of any further developments there.
It seems you change sailing technique downwind with mainsail in fairly tight, traveller close to centreline, using apparent wind like
never before. In more than 5knots it feels like you are beating all the way round the course !
Have a look at our web-site : http://users.iafrica.com/t/tu/tuffex/

Steve

All cats suffer the same problem when sailing high with a spinnaker. You can try flying the hull higher, this will balance it out a bit, but this is usually slower than sailing flatter and accepting the lee helm. You can shorten the pole, this will reduce it a bit. Or you can rake the rudders forwards giving a more neutral helm., the lee helm will still be there but you won't be ble to feel it so much.

Sorry this is quite short, but I posted three replies to this and they don't appear to have worked.

john pierce

Thanks for reply, John.
I`ve heard raking rudders forward will also reduce weatherhelm upwind, but too much will make the rudders "twitchy".
If I can reduce weatherhelm upwind in this way I may be able to rake the mast back a bit, which should reduce lee-helm downwind.
I`ll try it out next time out.

Cheers
Steve

Steve,

I looked at the Mosquito website. The Mozzie with a Spinnaker looks great!! I'll bet a fleet of those racing would be a real buzz to be part of.

Rob.

For one I don't agree with raking your rudder forward, at least not as starters. Raking your rudders should only be done after you are happy with all other settings and still want a little less rudderhelm. But when the tuning is done right you won't have to do this at all.

Question one :

-1- Under spinnaker, trying to head up onto a beam reach, the boat suffers from excessive lee-helm. Bearing off helps alleviate this, but at times it may be necessary to sail high.

I first have to dissappoint you here. Some spinnakers can not be sailed high. It is all in the cut of the sail and the experience of the sailmaker who made it. I sailed a few spinnakers on both cats and monohulls and the difference in quality is sometimes amazing. Some spis can be sheeted hard en loosely and remain easy to be controlled and lee helm is modest. Others collapse without notice making you pull hard on the sheet to prevent it resulting in massive leehelm.

So to a large extend you have to work with the spinnaker that you are given and spis from some sailmakers just don't fly well high. You will have to determine wether you spi is one of them.

What can you ?

Rake your mast back, accept a little extra weather helm upwind.

Shorten the spi pole but only when that baby is longer than 11,5 foot or 3,5 mtr. Your pole should be something between 3,0 and 3,5 mtr.

>>> (Mast is plumb, if I rake back I get weatherhelm upwind.)

Well yes, but a little weatherhelm upwind is not a bad thing. It will make your boat go better to windward when you load your rudders up a little bit. Only stop loading up your rudders when tacking becomes difficult or when the boat has a too strong a tendency to round up when you try the accelerate away from parking.


-2-- As the wind increases I find the need to bear off even more - a factor no doubt due to apparent wind moving forward making you bear off.

If you really need to point high than you can play with your halyard and try to make your spi more flat and reduce the force developped that way this should reduce lee helm at the same time.

Micheal Coffman wrote in oktober :

"The wind built to the most of the day as we came to Pensacola pass (maybe 8-10), and we popped the chute as soon as we could, even though it was initially above a beam reach. I slacked the halyard, the crew cranked the sheet, and we rounded double trapped and doing 14-ish plus. We drove above a F31 tri and the f18ht that had passed us. "


-2- I have been keeping the traveller close on centred, mainsheet in fairly tight, even in 5-8knots, as the gusts come I bear off, as they die I head up. Even in this wind range I find the highest I can "point" seems to be a broad reach.


I should centre my mainsail to much; in extreme cases you can have losed attached flow thus greatly reducing the forces on your mainsail which you desperately want to counteract your spinnaker induced lee helm. Maybe try the travel out a bit more and make sure you have attached flow (tell tales)

You should be travelled out to roughly 1/3 the distance between midbeam and the end of the beam. Start there, tweak the other stuff and then play a little with it and find out what works.


>> In under 5knots I can head up higher. At this point crew is on leeward hull, I`m sitting forward & inboard trying to raise windward hull. Head up in lulls, bear off in gusts.

This sound good. And all the time you should hear your crew working the spi sheet. When it is quiet for more than 3 secs give him and nutch. Most crew don't work the spi sheet in the beginning but they should.


>>As the breeze increases I move weight back & outboard, eventually getting crew on the wire in 12 knots plus.
Centerboards are always half-down.

You have rotating boards right not the sliding kind ? Maybe you should let them down and only play with them when all else is satisfactory. Rotating back the boards can only aggrivate the situation. It maybe wise to take this out of the equation till we know exactly what is going on.

It is to bad I don't know your boat at all, makes it more difficult to comment on it.

>> What do I do as the wind gets up above 15 knots ?

Sail deeper.

>>Are there any "newer" techniques to sailing fast with a
spinnaker ?

-1- Working that mainsheet so that the spi is just about to curl up at the middle of the luff.

-2- in very light winds role the jib away so that the spi fills better or just fills.

-3- don't double trapeze when flying a spi. It looks good and it is fun but it doesn't give you better downwind VMG. And often the skipper has alot less control over the boat which is somthing that is more important than when sailing upwind.

-4- try windwards drops of the spi. Just pull on the windward sheet while sheeting out the leeward one but keep tension on the sheets. At one point the clew will flip around your jibstay and than the skipper releases the halyard from its cleat and the crew quickly retrieves the spi. This technic is helpfull when you approach the c-mark with the spi on the "wrong" side. It safes you a gibe and the spi is on starboard where it needs be after rounding the B mark next time.

But start by practizing alot of sets and drops so that you work together as a team and can do drops and sets (both leeward and luff ones) in your sleep. This will greatly help in races.

This is it for now.

So first rake your mast back before you rake your rudders forward. Try it and then come back and tell us what the results were.

Wouter

On your webpage you wrote :

"I discarded the main sheet and played with the traveler sheet, which I occasionally dumped when we were overpowered. ... In 25 knots I found us having to almost run to keep control, which caused us to nose dive several times."

How strange it may seem but when you are running almost straight downwind and you are likely to dive; don't sheet out your maintraveller. Chances are you are to late to prevent decelleration and because you go slower the apparent wind is likely to turn from perpendicular to the centreline to behind your boat. By sheeting out your traveller you rather increase the projected surface and make sure you go into a proper gibe. Rather let the main traveller and the main sheet be.

Another trick used on sloops in heavy winds is to not set the jib to tight. Sheet the jib just tight enough so that it doesn't flap; it doesn't have to have a nice shape. Often with a spi the jib can be set rather tight and when you suddenly drop the spi the jib power up quickly and give a push to your bows. Or at least that is what the local F18 champion here advices to do.

Here apic of two Mosquito's with spis in South Africa



Wouter