Gybe angle vs speed increase required

[Fish 0]

Spin

If the wind builds you can run deeper or flat off, can still run hotter angles in the light, and you can keep the kite flying through the gybe, so don't suffer as much as gybing a gennaker where it must collapse and then build speed again.

Boat type & weight also make a big difference though, the average displacement caravan wont ever plane and suit running deeper wtih a spin, a light sports boat can plan easily and get a bigger advantage with a genny, heat up, catch a plane and soak with the apparent. That said, all new designs are genny only planing machines, probably other factors at play there though.

[Guest]

I have an opinion on this but was hoping someone out there could settle an old argument.

[Bogan 8]

Spin or genny downwind depends on the boat and the wind.

 

Fineline's polar numbers suggest that above 20 knots they are supposed to switch to the genny and sail hotter angles.

 

But there may still be tactical reasons to choose one over the other.

[PaulR 3]

I have a question : What sail down wind during W/L races, Spin or Genny ? assuming you have both options.

 

Possibly the one with the least chance of complete F%$#% Ups, either hoisting or lowering.

 

W/L races are short, to VERY short, and it all come down to crew work, being the biggest factor.

 

Then I would next consider the ability of the committee / Race Officer / Mark layers to lay a true windward / Leeward course, without bias in current free area of the sea.

 

Lastly tide would be next. All this assumes that there is a suitable steady breeze.

 

Most W/L races have only ONE CLASS of boat per division, and the different Class Rules generally state what sails are permitted, sizes, how they are measured, set etc.

E.g. See S34 Rules = Big Kite always

 

So being a true W/L race then it's "Spinnaker" for the flat off run or hot angle because of the tide off Westhaven.

 

So IMHO, if you are considering a W/L race under gennaker, then the course has knot been properly set to the wind and you should protest the committee / Race Officer, that kind volunteer just trying to do his best for others.

 

Perhaps with Gennakers and Spinnakers there is a valid arguement to bring back the original Olympic triangular courses with 2 x reaches 2 beats but one flat run to finish at the Start (leeward) end of the course to allow for several races in the day.

 

However it was a real pain spending all morning going out to the gulf (off Torbay), do 1 or 2 races and then spend all evening getting back.

 

Perhaps WEST of the bridge is a possibility.

[Fish 0]

 

Perhaps with Gennakers and Spinnakers there is a valid arguement to bring back the original Olympic triangular courses with 2 x reaches 2 beats but one flat run to finish at the Start (leeward) end of the course to allow for several races in the day.

 

However it was a real pain spending all morning going out to the gulf (off Torbay), do 1 or 2 races and then spend all evening getting back.

 

Perhaps WEST of the bridge is a possibility.

 

OR

Move to the tropics, Weiti winter series is all Olympic courses.

Near free parking in the river, or race out of Gulf Harbour. Quality fleets, flat water...

[Guest]

Mmmmmmmm that dosn't quite tell me what is the best sail to use when flat off going to the bottom mark.

So far spinnaker seems to get the vote.

The question was " if you have both options"

 

Cheers

[PaulR 3]

OK nice & simple.

 

USE the SPINNAKER for W/L.

 

The Gennaker is a reaching sail, not designed for flat running and a W/L race is too short to do wide angle reaches as you will be getting out of contact with the opposition and failing to cover those behind you.

 

COVER, COVER, COVER and no F^&%% Ups

[markm 30]

fwiw,

 

No doubt there's a mathematical arrangement of displacement, length and sail area which would give an answer that people could argue over, but as noted earlier yes, gennakers can work on w/ls if you're light and quick enough.

 

From what I've observed, it's pretty much a kite game for any boat slower than standard E1050 pace, accepted the lightest and smallest of the sports boats.

 

As you go up in size, so you need to be quicker, kites seemed to still be the best on a F40 but 40s much lighter or quicker than that seem to make gennakers work all the time without too many problems.

 

For us, our feeling is in under 8kts or so, a gennaker isn't a bad option but that's in part because in the light you're having to sail higher with a kite anyway and of course our gennakers bigger than the kite which doesn't hurt.

 

Above that, we'd guess the kites always quicker ddw but once you get up over 18kts or so your angles under gennaker are somewhat closer to those of a kite than in the lighter air and ease of handling becomes a more significant factor, particularly on shorter courses.

[Guest]

OK It seems most of us agree. I would and always have used a kite DDW during W/L races if there is an option.

Of course there are variables but in most cases the above would apply.

 

I have been in discussion with a bloke over the last 2 or 3 years on this one. Even got to the point of ringing several sail makers and designers. Also thought I prooved it in one race where we sailed away from him down hill with a kite while he sailed off on a huge angle with his gennaker. Up till then we were very close together. Still he didn't believe me and had a bullshite excuse for getting kicked.

 

Hope he reads this. His come back will be interesting.

[wal 27]

On Demonstrator we would have been shiteloads quicker flat off with a spinnaker in anything above 7 and below 15 knots TWS sailing DDW. Below 7 everyones looking for hotter angles, above 15 we're getting down there quick anyway. I couldn't be arsed running 2 systems. We did it on Gorilla Biscuits - worked well

 

Lucky for us it's hardly ever above 7 and below 15 in Auckland.............

[Pumbaa 9]

I had this long running argument with a friend of mine, I had the opinion that gennakers were better in the lighter airs as they sailed angles better then spinnakers took over as the wind strength got higher until going straight to the mark was as fast as the boat could possibly go, you can't get better than that. Any way at one stage we asked Ken Fyfe, Craig Gurnell and a whole bunch of others for their opinions. This is an interesting response from Steve Thompson

 

"Hi Tim, yes its always an interesting question. One I can answer with good authority on the type of boats I design as I have done extensive testing both on and off the water.

 

Essentially an asymmetric sail is faster below say 8 knots and above 12. There is a gap where the symmetric spinnaker is about the same speed between say 8-12 knots, but there also may be a very small wind range where the symmetric spinnaker is faster around 10-12 knots, but there isn't much in it.

 

I hope this helps, Steve.

 

I reckon most polars show 30 degrees of angle returning the best value, so my pick would be gennakers. More sail area, easier to handle and have a designed entry and exit.

[Guest]

Hey Tim, It took a while.

 

Thompson is refering to testing his own designs only. I think most sailors appreciate that a gennaker could be quicker in the light by sailing angles but I dont believe it would get us to the bottom mark quicker. We have proof of that ..Remember ?

 

By the way, Why didn't you print Craig Gurnell response. After all he was with me when we sailed away from you with a spinnaker while you ran a gennaker. IN LIGHT AIR !. Also had Dave Ferris with us.Between the three of us I think we had enough experience to at least get that right. We had the option of a gennaker but it didnt even get a mention. And further to that, Results speak louder than words. Remember ?

 

Read Wal's bit about Demmonstrator. It is a Thompson.

 

Further more, A spinnaker should be set by adjusting the height of the pole and by using tweakers to adjust the trailing edge thereby creating an entry and exit. Just like a gennaker. There are books around that go into detail about that. ie. when to raise and lower your pole etc.

 

Plain Sailing I believe.

[Pumbaa 9]

So you're still holding that race up as the definitive moment, I'll shed a bit of light on it for some (nearly every one on the planet) that weren't there that day. The opposition in the red corner them: Jagged Edge SR26 sailed by Mark Beachbum, Craig Gurnell, David Ferris and Sharon Ferris as well I think. In the blue corner, us on our 1979 Harold Evans 780 express Coyote Blue sailed by Me, my Dad Bob and Amanda my wife. Third time out with a gennaker but first race with and you passed in last mile when I took the wrong side to the finish. Is that the race or is it a different one you're talking about? Nah that's the race isn't it.

 

Gennakers even if it's just because they're harder to chinese gybe. They're easier to gybe, to set, to drop, I don't know why I took so long to get one and if the difference is so slight we can argue over it for 18 months and still be able to score points. I'll stick to the gennaker until it's blowing like stink (35knots plus dead down hill in a swell) and I've got a ride on a fat old IOR when the poles dipping in the water and the boats rolling so much your puke is making pretty patterns in the air. Ahh memories.

[Marshy 30]

On the SR we have always found a chute faster downhill than a gennaker. In the really light we have played with the big gennaker and it has worked ok as you are running angles already. And again in big breeze downhil the gennaker works because its enough apparant.

 

It really depends on the boat and the ability to be able to build the apparant boatspeed up enough to combat the extra distance sailed. The SR's are pretty squirty little boats, but that said they still squirt with the big masthead chutes up so you can run 20 degree's or even 20 degree's lower not much slower as they are sliding as it is.

 

The only thing with that i guess is how big ya balls are in an SR as they have been known to spit a few people flat off downhill at pace! Something about family frighteners? New rudder has sorted that for now!

[Guest]

Yeah you were doing well in that race as you do in the light. Only mistake was "going on the wrong side to the finnish". Thats because you ended up going into Te Puna inlet on your hot angle while we sailed into Keri inlet with a spinnaker.

[Kiteroa 8]

I think the solution is a pin head main and a massive A2 gennaker hauled to windward with a long canting prod. Then you can fill the kite out the back of the mainsail and get a lot more drive running deep. We carry this kite up to 20 knots and can run almost as deep as the symmetric boats. Provided we don't drop it in the piss it's a dream sail to use.

[noddy 0]

Ahhh!.. A blooper.

 

to say a spinnaker is better than a ASail is dependent. on cut, condition, of each sail. along with class regs on pole/prod length, mast position, mainsail size, and general desugn (Fast rraching hull form versus a good dead downwind boat. Among many other variables.

what boat do you have?

[Guest]

Went fishing today. Did 35 mph ( old speedo ) DDW without hotting up.

Those 115 HP Johnson outboards generate quite a bit of apparent wind.

 

Got a 13lb snapper for my trouble.

[samin 0]

Summer Brezze wrote

"VMG of wind gear data is not as good as GPS via waypoint."

 

Sorry but I think if you are sailing upwind /downwind - VMG relative to the the wind is the only thing that matters. (I.e it is the fastest way up upwind relative to the the true wind direction) GPS VMG to a point is almost worthless IMHO for upwind downwind.

 

Would love to have accurate instruments to get this data on my small Cat.

 

Cheers

 

Shane

So sb. if the bottom mark is on a bearing of say 180 degrees and the wind veers to a direction. of 270 degrees then you would sail the best vmg relative to the wind with no thought to where the mark is

 

sorry sb but the best velocity made good to the mark is the fastest way. Vmg to the wind will not win racea but will make the speedo look good.

 

Actually I had this discussion with Clipper during the night race to Kawau!

 

My opinion was/is if your VMG running i.e not laying the mark the important number is VMG directly downwind. Speed to mark is not important because if you are gybing thru 90 as we do your speed to the mark will be zero when you gybe on the layline. Using your method you would gybe 20 times staying in middle of the course to keep your speed to the mark high! thats not the fastest way to get to the bottom mark!

Clipper you reading this?

SB is correct, Summer Breeze is confused!

[samin 0]

On Demonstrator we would have been shiteloads quicker flat off with a spinnaker in anything above 7 and below 15 knots TWS sailing DDW. Below 7 everyones looking for hotter angles, above 15 we're getting down there quick anyway.

 

Same thing I find on the 8.5 Multihulls but its flatter/small Genny for the lower and higher end and Deeper/bigger Genny (not spinnaker) for the middle range.