Full Spinnaker

[occasion]

Has anyone rigged a Telstar with a full spinnaker? I entered a race last week with a long down wind leg and couldn't keep up with the monohulls with full spinnaker, even tacking downwind.

Sandy
Occasion #368

[Ron]

Sandy -

I'm assuming that you're talking about a symmetrical spinnaker. I'm not sure that a symmetrical chute will outperform an asymmetrical on most mult-hulls. Note that USA17 did not have one even with their huge sail budget. Neither did the Swiss cat. You also won't find one in the Corsair options book. I'm not sure if I've ever even seen a trimaran with a poled out symmetrical.

You've got to take advantage of a multihulls higher increase in boat speed that comes with an increase in apparent wind. When I race with monohulls on a windward/leeeward course (I try not to though), we rarely sail in the same direction as the mono's, regardless of sails, and usually get to the mark sooner. The multihulls tend to be out somewhere in "left field". You want to fall off going into the wind, and higher when running. How much depends on a number of factors, and is guided by maximizing your Velocity Made Good (VMG). I'm perhaps 15 degrees or more lower on a beat than them, and about the same amount higher downwind. This is asymmetrical territory.

Sailing on the same sluggish downwind course as the monohulls would be giving away one of your big advantages, and won't get you there any faster. Since you've lost apparent wind by doing this, poling out a chute at that point won't really help. Hey, USA17 was doing mid-30's in about 8 to 10 knots of true wind with an asymmetrical. It's apparent wind was probably 25+ knots higher than true and it was gliding thru the water at well above 30 knots. On a dead run it wouldn't even exceed wind speed.

[wingman]

I race often with a asym. I use a J-80 spinnaker that fits well. In my experience, the lightweight boats can keep up with us in light air as they go almost downwind with symmetricals. In heavier air, I leave them behind, but the big boats, over 30 ft, will outrace me. If I can surf the waves, I can do well. As Ron says, VMG does not lie. When you practice, put your GPS on a mark directly downwind and try to find the angle that gives you the best VMG. I find that it is usually between 140 and 160. When we have a non W/L race and we get a reach leg, then we can beat all the smaller boats and some of the bigger ones. You should at least trail the centerboard unless on a beam reach, but do not forget to get it back up when you turn upwind, or you will slide!

I race a lot against an old (lighter, one outboard) Gemini with a symmetrical spinnaker and a main that he can get to go to 90 degrees. He is very hard to beat downwind. Of course, he is 34 feet long with bigger sails. he is also a great sailor.

Did you get the standard spinnaker that comes with the boat? It is cut a little different from mine, as it has heavier cloth, less area, and a lower clew. I think that last year I put a comparison of the measurements on the forum somewhere. It may be more of a reaching spinnaker than mine and that would hurt on a straight downwind leg. You may also want to get a boom vang to take out some of the twist out of the main. With the swept shrouds, you hit the spreaders quickly and I do not like to poke holes in the expensive main.

John

I have found that in very light winds, the wing-on-wing is good for a directly downwind mark. I am talking about 2-3 knots on smooth water. it is hard to hold, but if you sail slightly by the lee, you can keep the asym full without jibing the main.

[occasion]

I have been told that a polar chart can help define the best VMG downwind. The Telstar wind meter gives VMG upwind. Does anyone have polar charts?

My GPS, alas, doesn't give VMG.

Sandy

Occasion #368

[Ron]

I think there are some blank polar diagrams in the owners manual. Since every boat is a little different and we all sail in different areas, it would not be a bad idea to fill out the charts for your boat in your sailing area. Not an easy job though. You'd have to collect the speed data from a number of wind angles and at a number of wind velocities. I haven't done it yet either. Maybe next year.

The wind meter will give you the vmg based on the wind direction and not on a course headed towards a given mark. It would be rare to be dead downwind of a race mark at a given moment.

[drsm]

Should the polar diagrams be filled out on the basis of apparent wind or true wind (or does it really matter)?

[Ron]

I've seen several variations, including true wind speed and true wind angle, apparent wind speed and apparent angle, and true wind speed with apparent angle. I suppose it doesn't really matter as long as you know what you did and how easy you can interpret this when needed. I'd favor either all true or all apparent - less confusing when you're out on the water.

[drsm]

I've been toying with filling out the polar diagrams, but just wasn't certain which way to go. I've been leaning toward apparent wind speed and direction, simply because that's what I monitor the most. I think I'll go ahead and do that.