Sailing Angles and VMG

[Alan#38]

I have found it very difficult to sail downwind in 5-8 knots of wind.  I can't seem to find the fast right angles in this wind range.  I seem to migrate to about 90 degrees apparent and I think that may be too high.  I'm also going in to 1.5 to 2 knots of current, so that is an additional complication.  Any advice would be appreciated.

Also - has anyone used the Velocitek S10?  http://www.velocitekspeed.com/product.php?p=s10
It looks like a handy tool for learning the right downwind angles, but I'd like to hear from someone who's used one before I buy.

[Chris Shaughnessy]

We bought the mk1 version a few years ago, but have not really used the VMG mode, just speed.
Speed alone is a blast to see when you're up on a plane.
I believe the later models are a bit more flexible with changing mode (the company does seem to listen to feedback).
The unit itself is quite tough and very visible - be even better when I get a bracket to mount it on the mast with (I don't think they sell one, currently we velcro ours to the side decking up near the jib tensioner cleat).
The new replay course on your PC function sounds great for after race analysis.
(note : I think the current class rules may outlaw use of VMG type instrumentation in competition).   

[Justin Scott]

The Velocitek is not allowed in class OD regattas by the class rules.

However, one of our local fleet members, has access to one (courtesy of a current Olympic/Paralympic campaign) and has used it in one or two local club races as they experiment with vmg angles etc. They then circulate their thoughts to the rest of the fleet via email. I will ask them to post this on the forum so it is more widely available.

The velocitek is a very cool toy. It is currently not allowed because it is  a)Expensive b)VMG would be an advantage c) Would appear to compromise the "simplicity" component of the class philosophy. However it is your class association and your class rules. We want a period of rule stability after all the recent updates but feel free to send suggestions. The Velocitek is certainly acceptable for PHRF racing and practising. Please post your findings to share with others.

Re 5-8 knots downwind. We get our fair share here. Experience and time on the water pays. There is no huge change in the power curve, as in 10 knots, when you get on the plane. There is however a detectable kink in the power curve as the boat picks up speed and the apparent wind goes fwd. Head up, paying close attention to the hull speed thru the water, as soon as the spinnaker seems to pick up pressure and the apparent goes fwd, you have found the sweet spot. 

[Paul Gillard]

I have an s10 -( i dont have other vipers around to race and just race fleet), however I have not used it on VMG mode yet (hate to admit). On harbour courses you really only need speed and a compass, however I must set it up on VMG for a w/l. 75% of my sailing is in winds of  18knts plus and I try and keep things simple then, however I want to try it out in that mode soon as I sail against symmetric kites on w/l's and you need to be on the right angles to try and keep up with masthead kites on flat runs.If i get any useful deductions I will post