hi all,
a noob Q on downwind sailing

which is better for vmg

a. tacking downwind through 90degrees with traveller all the way out and apparent at 90degrees, BUT tell-tales back of main stalled

or

b. tacking through 90degrees downwind with apparent at 90degrees but with traveller pulled in enough to get tell-tales back of the sail flowing

Downwind without spi my traveller is around the jib line. Downwind with spi, it's closer to the center. The only time I release the traveller all the way is to pass the upwind mark in hight wind to make sure I'm not thrown overboard when I round it.

You want the back tell tales to flow at all times.

B

The tell tails show you how the wind is flowing over your sail. if they are stalled... you have flow issues. The outside (leaward) tales are more important to have correct flow... but ideally you want both lea and windward to have correct flow...

Oh yea,... in case you dont know (and you say you are a newbie) an important part of downwind sailing (that took me 25 years to learn) is that you don't want to sail in a straight line.. you want to head up to gain speed (and apparent wind) and then slowly fall off. This of course means adjusting the sheets of all sails as you fall off and head up...

For going downwind without spi the most important thing is the jib trim. Let the jib out as far as you can while maintaing a round full sail (not flat because of letting it out too much). With this setup, find your fine line going as deep as possible while letting the leeward jib tales always flowing straight back. Now set up your main to fit the picture and steer to the jib tales, always on the edge of stalling the leeward tales, but never stalling them. This will be roughly 90 degrees of aparent wind, but not always.

Erice:

Spend the $30 on this https://store.catsailor.com/pc/viewPrd.asp?idcategory=99&idproduct=6437 It will teach you all you need to know about flow and telltales and cut years off the learning curve. MUST for every new sailor.

Doug

Eric
I find that your B is flawed. If the telltales are stalled then you are over sheeted. The traveller would need further easing or the boat would need to be headed up.

You also didn't mention mast rotation. An aftermarket mod to the 5.2 was to put a rotation forcer on the mast for downwind sailing.

thanks for the replies guys

- it's my 1st cat and i've have it for just over a year now after a couple of years on a 13foot dingy

- do have rick's cat racing for the 90's, and also the earlier hardback version

- up to now downwind i've just been letting the traveller all the way out and then steering the boat so the bridle fly goes out sideways. jib generally gets blanketed by the main and is very difficult to set in our light winds.

- recently realised that the main's leeward tell-tales should be flowing and not stalled. can steer off the wind to get them flowing and go faster but then am tacking downwind through around 120 degrees so vmg suffers.
so rather than steer off to get the back tt's flowing i've only recently clicked that i can get them flowing by pulling in the traveller and STILL head down with apparent wind at 90degrees, (thanks for confirming that peps)

- our lake is only about 1 mile by 2, so no spinnaker required and the east arm has very fluky winds as it is surrounded by mountains from the prevailing nor-westerlies

http://www.youtube.com/watch?v=BNAsxV1ltMU

- because the lake is basically too small for a 17foot cat, average time between tacks is probably something like a minute. quite good training as it's so technical but sailing solo you tend not to muck around too much with inhaul, outhaul, luff tension and dagger board positions or you'd never stop moving on the tramp.generally not much time to tune the sails to the nth degree

- the small lake size means good pointing ability is very important and it is generally better vmg to pinch upwind and stall the main downwind rather than toss in 2 or more extra tacks of only a 100yards.

- sailing with jib solo means most upwind tacks are not fast as after bringing the bows across the wind i let the jib backwind and then the boat slows almost to a halt while i hold the tiller with my foot, uncleat the jib, pull across and re-cleat on new side, grab the tiller again, pull in the main and steer deep to get speed. takes even longer if coming in/going out on the wire

- positive rotation kit for the 5.2?, would love to see some pics but again would probably be too busy solo to remember to uncleat it all the time at the end of the run

- so far have just been using the gps passively to record the tracks and to show sailing speed
think if i use it a bit more actively by actually punching in a route around the buoys that i can then use the vmg functions to better experiment different headings, settings

- i'm about the last sailboat on the lake now as it gets colder and colder. before the end of the year ski fields on the mountain tops hope to be running and by then i'll have broken the boat down and put it in storage

i can clearly see in your video your tell tales are stalled.... (kidding)... great video to express your sailing conditions....

we want to see one of your skiing in a few months (with gps/speeds)

Always avoid backwinding the jib during tacks...that stops the boat and can even start it backing up...A properly done tack should see a small speed loss and good accelaration out & onto the next tack.

Re-read the section in Cat Sailing for the '90s about roll-tacking. Your basic approach should be to have a hand on the cleated (or uncleated if light) jib sheet while sitting in your normal position before heading into the tack. Main in pretty tight. Shift your weight aft along the hull as you begin to turn up...then release the jib, letting it flog as you keep turning up...now shift your weight all the way aft, to the rear (still) windward corner. THe idea here is to lift the bows a little bit, effectively shortening the waterline and to create a pivot point on the old windward rear corner. Try to "Carve" your rudder blades smoothly through the water, not jam them over hard making lots of spray/drag. Keep the main in tight until just prior to going head to wind...then be sure to release it, easing at least one arm length of sheet . Keep rudders turned without flopping them back & forth as you pass the tiller extension behind the main sheet blocks. Move to the new hull, keep turning off wind. Do not sheet the main yet...do the jib first...but don't go forward until you're past head to wind to avoid stopping the turn and risking going into irons. Once the bows are turning nicely away from the wind and the boat begins to move forward, then sheet on the main. If you do this too soon you will end up in irons.

Practice this technique hundreds of times and then do it some more <img src="http://www.catsailor.com/forums/images/graemlins/crazy.gif" alt="" />

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I will post some up tomorrow of my set-up for you to see.