My mast has a large black band of carbon all around it. As long as the measurement is concerned only with the bottom of the band I'm fine. Right? <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />

I was quoting from the measurement spreadsheet (see link above).

I think I am correct in saying the F16 sail measurement is slightly different to normal SCHRS (only luff length of mast rated in area.) Is there an arguement for the mast to be banded upon measurement of the mainsail? Mainsail measurement requires the luff length to be measured under tension. Banding would make it apparent that the luff length (and rating) was being exceeded.

Cheshirecatman

Hi Pepin
When I was sailing an R and bought a new Landy F16 mainsail I had to move the boom/goose neck below the mast rotator bracket but it worked out really well. I had to also adjust the outhaul system to the max length of the boom, that boom was a rectangular shape. If you're looking to change mains and need photo's info on what I did please don't hesitate to contact me.

Isn't that section acting as a boom vang? As you release main sheet the boom wants to rise. The lug in the lower sail section is in the sail track and that sail panel pulls tight, stopping boom lift. Vangs are something cats never seem to have.

Just a guess...

As it was explained to me recently, cats do not have vangs because it would impair mast rotation. With a vang you lock the mast and the boom together and the mast can't rotate freely anymore. Monohulls with vang do not have rotating masts.

So if your mast rotate: traveler. If it does not, you get a more convenient (IMHO) vang.

My Arrow had a Vang and the mast rotated fine. The Arrow has a fairly low aspect rig compared to modern cats though. I think it would be scary how much tension you would need on the vang to get decent leech tension on the big head mains. Can you imagine the boom you would need to handle that sort of load?

That lug would never hold the tension required to keep the boom done.

Pepin, the GP sail fits the older style Stealths masts fine just as it is, both Nick and I have not had any problems. <img src="http://www.catsailor.com/forums/images/graemlins/cool.gif" alt="" />

The lug is for the outhaul to pull against, sail without it in the track and the sail near the boom get very ugly. My Mosquito has a vang, very useful for sail shaping and forcing rotation on light days.

I wonder why the Goodall F16 sail for the Viper is different then the Blade/Taipan on the same mast?

Darryn
Mozzie
1782

me too

One of the blades at the club is currently carrying the goodall sails, and the main is the same as the viper big head main. The differences lie in the blade's jib, which has a longer luff length and the spinnaker, which seems to have a longer luff length too. As far asi i can see, all the big head mains coming out of the goodall facility on the taipan, viper and blade are the same.

I crewed on a skiff a few times over winter... It had about a 24:1 ratio on the vang, and he would wrap it around his hand and CRANK it. This caused a lot of mast bend... but more amazingly it cause the boom which must have been about 80mm diameter to bend! And his rig was substantially smaller than a cat rig!

I can't speak for AHPC, but Greg told me that he would build the Viper main different to the Taipan because.

The spreaders are different, the mast is longer,the boom is shorter, also the loads are higher because of extra width and weight.

The spreader difference and weight apply to the Blade Vs Viper also. Although I would expect the Blade and Viper main to be closer in design than the Taipan.

In reality though, you will easily get more variation from different manafacturers making sails for the same boat from my experience. <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" /> I don't think sailmaking is the exact science we all wish it was. <img src="http://www.catsailor.com/forums/images/graemlins/wink.gif" alt="" />

Pepin, are you planning to acquire new beams from John P?

Of course, you'd need a new tramp as well or at least insert a widening strip down the centre of your existing tramp. However, you'd then (with a new main) have a fully optimised Stealth F16 and have increased the value of your boat? Psychologically too, you'd feel that you were on the pace.....

It's just what I would do in your position if I was planning on new sails, go the whole hog!

Definitely not. The 0.02% gain in performance I will get by widening the boat by 8inches will not compensate for my poor sailing skills. I'd say I should improve the man first, the material second.

A F16 main on a type R platform was great at going upwind, don't ask me why but I'm sure it points higher. We have had quite a few beer discussions at the bar over this but no one has come up with a clear answer as to how a slightly narrower platform (200mm-8inches) could point higher but it does. Also, in the lighter stuff you can get the windward hull out quicker both up and downwind and the platform could be stiffer. So all in all there's extremely little overall speed difference between the two. Like Pepin admits it's the nut on the end of the tiller that wins, loses races in most cases.

Ahhhhhh! - NOW I understand!! - It's not the 8 inches themselves but how you use those 8 inches? <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

FYI, many non apparent cats have vangs. When going downwind square with the traveller and main sail all the way out, it is important to keep the boom low to present max sail area to the wind.

My old Dolphin had a wing mast like a super wing and never experienced any promlems with rotation. Also had a vang on my old Mari 4.3. Paper Tigers, Mosquitoes, Arafuras and Quickcats I have also sailed had vangs.

I use the vang upwind also in the light stuff, vang sheeting like a Laser. While some Mozzies run square downwind I find it quicker to gybe downwind, using apparent wind, the vang helps over rotate the mast.

If the Viper rig has more grunt then...? Perhaps I miss the point.

Darryn