Brobo

>>there must be max downhaul to get the shape that way,....

Downhaul AND bending away of the mast top.
It appears the top of the masts are bending away to leeward. Intended wingmast behaviour. This depowers a boat like nobodies business.

>>they are depowering the top 1/3rd of the sailplan to keep the Uni in balance upwind......not very efficient, don't you think?

It also tends to hurt pointing.

>>does the 18HT rule allow for a sail smaller than maximum s.a.?.....or is one committed to use max s.a. in all conditions?

Smaller is allowed. I don't remember wether you would have to use the same suit of sails for the whole event.

Wouter

Wouter, Scooby and all,

It is no doubt a great event.

Nothing like great sailing to make the week go by faster

He is my question,.....for the ICCT,.....would it have been possible for a F16 team to participate? These folks know Uni with spin sailing, 1-up and 2-up ,...and I am sure their skills could transfer to the 18HT.

Not taking away from the Tornado sailor one bit, understand this please.

...but there are a bunch of F 16 contenders in Europe, USA and Austrailia that are top notch Uni sailors too!

....even invite a F 17 representative ( and let them pick a crew, of course)

....how about a invite for the A Cat gang too ( ditto on picking a crew),....intersting things might happen

regards and good sailing,

Bruce
St. Croix

Before this thread goes places we don't want to be, I would like to express my desire to not discuss F16's in a thread about F18HT's and ICCT. This kind of thing sort of quickly degenerates into a pissing contest, at least it often did so in the past.

With regard to your quesion. I'm sure that any crew from any class can be in the ICCT. There are certainly HT charters available, if not participantion slots. Such a crew would just have to lay down the money and do it.

I guess it all comes down to a personal wish to compete in an event like the ICCT and the willingness to pay the cost for such a campaign.

That is all,

Wouter

The sails almost looks like windsurfer sails trimmed for a lot of wind. Have to be quite an amount of downhaul applied..

The F18HT class rules does specify that you can just use 1 set of sails in the same event. So the sailors probably brings their best all-round sails.

The snuffers on the two boats above is quite different. One looks like a Marstrøm snuffer with a shorter pole, while the other is the 'regular' bucket. Looks like 'the optimal' solution has not been found yet, and nobody uses the Marstrøm 'snail house' snuffer.

Anyone can enter the ICCT, you have to submit a entry, pay the fee and bring a boat. Check out the SYC website. If the response was overwhelming, the hosting YC would have to make a determination on how many challengers they would want to accept, since match racing requires umpires, you need a significant amount of on the water support for each race. The ICCT has one umpire boat per competitor racing on the water. So, the number of competitor boats would largely depend on the number of judges the RC could supply or how long or how many races you needed to run.

The HT class supplied charter boats for Johnny and Charlie and Enrique's team. Mitch and WF brought their own boats. So, if someone from the uni world, or any cat class wanted to compete, I am sure that the class would do its best to support them.

With regard to the sails, you can go smaller if you want according to the HT rule set, its a max 20sq m main, but you can go smaller and you can reef if you want.

Changes in equipment are permitted in the case of breakage, or if the event decides to permit changes then this overrides the class rule. Southern YC is sponsoring the event, so the class's position is that they have the final word on rule interpretation for this event.

Bill Vining
HT Class

Rolf and Bill,

Thanks for the good answers.

Looks like a great event.

The posted day by day pictures , make it fun for us too.

Thanks again.

So, for example, the Stealth 18HT , out of the UK, could have competed, if they coordinated their end of it, correct?

As a spectator, it would be good to see the different designs compete

regards,

Bruce
St. Croix
I-17

hello catamaran friends,

it would be beautiful to see javelin, ventilo, eagles and stealth or the new tomcat 18ht from france

the icct pictures are great

steve

Did you notice that the sails on most of the boats seemed to come from Ullman?

Pat

Studying the photo with the 2 usa boats too. You can't tell how much the top is twisting off from a side view. Also you can't tell how much bend to leeward there is from a side view. If that isn't a hollow cut into the leach between the battens then there is serious leech flutter though. looks like it's sailcut to me.
you can see that the mast rotation is pulled in pretty tight, it almost looks like the top of the sail is backwinding a bit up forward.
always enjoyable to see good shots of cats powered up.

I dont think the sails are cut with a hollow leech between battens. Look at the pictures here for a better view.

Besides, what would be the design theory behind such a design? I know there has been some research into why some sea mammals have similar profiles on their appendages but have yet to se a conclusive report (more information on this is always welcome).


Take a look at a windsurfer sail with lots of downhaul, you can see the same effect on the shape of the leech there. Hence the conclusion that lots of downhaul was applied. You might even see it on a cat, if you dare to apply enough downhaul and the sail is cut with a large roach.

It's the mast top bending to lee. I have the same effect on my F16 and even saw it on skiffs like the 49-er when the gust hit the top of the mast. This bending off makes the leech extremely loose in the upper part and it wobbles as a result. They are depowering these boats likely nobodies business at 2.5 mtr width and 10 mtr mast featuring 20 sq. mtr. mains I'm not surprised. Like I said I've seen it on my 2.5 mtr wide and 8.5 mtr by 15 sq. mtr. boat as well in high force 5's

Wouter

The sail on Johnny and Charlie's boat is Cuben fiber, so it is going to hold its shape differently (so I have been told - you guys might help me on this one.) I hear it is very light weight. Their spin is also very light weight, a couple of pounds less.

WF and Bob were sailing with Ulhman Pentax, (the smoke colored sail)

Most of the Spins are Ulhman's - the most current shape comes the design that Jay Glaser and Peter Johnstone worked out.

Bill

Wouter,
By the way, we dropped the "F" - its 18HT now.

Thanks

Bill

to all,

As Wouter and others note, the max downhaul is bending that mast above the hounds to the max also, opening up that leech.

Also, as mentioned, the mast rotation is minimal, so the related downhaul induced mast bend is on the long axis of that mast.

Further, it may be or not, the top 3-4 battens may have been switched out for solid glass ( re; no bend) battens, due to anticipated wind conditions. The only reason for this is to control power ( inhibit it) at that part of the sail plan. I read about this( and other tuning tips) from an Aussie T 4.9 champ, which can be found on the F-16 forum on this URL.

By looking at the way those battens are acting ( no bend seen), it would be a fair statement to suspect very stiff battens.

Uni sail/mast control is an entirely different realm and it is great to see these experts set up their rigs for different weather.

great sailing!

regards,

Bruce
St. Croix

Bruce



more likley that the battens have been put in the wrong way around. We've been doing this for a while in Hurricanes and Tornado's when it is windy. In fact My Hurricane spent all it's life with the top couple in the wrong way around.......Does NOT work on the 17 Mind.....

>By the way, we dropped the "F" - its 18HT now.

Ohh, I didn't know that. I have noted it now.

Thanks,

Wouter

>>The sail on Johnny and Charlie's boat is Cuben fiber, so it is going to hold its shape differently (so I have been told - you guys might help me on this one.) I hear it is very light weight. Their spin is also very light weight, a couple of pounds less.

Please correct if I misunderstood but are you saying their spinnaker sail is a couple of pounds lighter than standard ?

I know for certain that the 1st spinnaker I bought (1999) was made of the most basic, heavy duty and low costs spi nylon that was available and that it weighted in at 1222 grams (electronically measured at the groceries) = 2.7 lbs. (source : ) I would love to safe even 1 lbs on that. It was 17.5 sq,mtr. but still the cloth itself is not the heavy part, the reinforcements and eyes at the corners are.

What kind of cloth were they using ?

Wouter

>>As Wouter and others note, the max downhaul is bending that mast above the hounds to the max also, opening up that leech.

No Brobu that is not what I said. I said it is the top of the mast bending away to lee. This is NOT the same as the mast bending BACKWARDS under downhaul.

This characteristic is typical for wingmast on cats, something Petrucci pioneered on his A's in the past. And I really mean wingmasts here not teardrop shaped masts like the Hobie and Nacra variety. These wingmasts are very flexible over there minor axis and when the mastrotation passes a certain minimumal angle the top just bends of to lee. In some case even quite considerably. Skiffs (not wingmasts but very bending glass tops) have the same behaviour.

This is one of the funny aspect of wingmast rigs and great fun. You can finetune the whole rig with just the mast rotation. A little more rotation and the leech tension stiffens up the mast top and lifts your hull and gives you power. A little less rotation and quite quickly the leech tension is insufficient to stabilize the top and it bend off to lee with each gust. Thus spilling lots of air and make you accellerate without any lifting. The effect can be quite dramatic. On my own boat this is the way to totall calm down the vessel even in winds way beyond 20 knots.

>>Also, as mentioned, the mast rotation is minimal, so the related downhaul induced mast bend is on the long axis of that mast.

Although downhaul is important on wingmast rigs it is not all-important. Mast rotation becomes more important with increasing winds because of the way the top behaves. At least it is on my wingmast rig and I suspect that the 18HT are no different here.

Wouter

Wouter,
Yes that is correct - the spin that Johnny and Charlie are using is lighter by at least a pound. I was also told that the material that they are using didnt absorb water either, which is big plus.

I will find out the material for you.

You are right on track about the Bimare HT mast. However it takes a certain weight on the wire to get it to act that way. It bends off in the puffs better with a combined crew weight of about 380lbs.

Bill

Wouter,

Good points on this important technique.

So, from looking at the pictures posted in this thread I the USA vs USA one),....is the photo angle sufficient to determine what the top of the mast is doing?

One can see from the spreaders, an approximation of mast rotation, yes. I appears to be minimal mast rotation.

Plus, we can see the effect on the top 4 sail panels.

So, if there is enough visual support, which is happening....in your opinion ( or anyone who cares to venture an idea)

.....mast bend-to-lee? ( bend on minor axis)?

....or mast bend-to backwards (bend on major axis)?

regards,

Bruce
St. Croix