Rig tuning advice-any simple tests & solutions?

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RobBrown

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After spending a weekend with an experienced Yachtmaster O on board my boat, he identified significant differences in performance on alternative tacks when close hauled and pointed to rig set up but unfortunately left before I could quiz him on possible causes & solutions! Having been made aware of it, in subsequent sails, I can definitely see that boat speed on Starboard tack is down about 30% or more than on Port.

Any advice/suggestions on likely causes of the symptoms, easy checks (someone mentioned measuring shrouds with the spinnaker halyard?- I don't have a tension meter) and possible remedies?

Boat is a Moody 29 fin c babystay, shroud & backstay tension is adjustable, but only via usual bottlescrews.

Rob
 
Those guides are good.
It's going to be a lateral issue. Apart from the possibility of the mast not being vertical, you haven't added heating and not got the weight distribution of bottles and batteries right, have you?
Someone on our moorings did that and ended up with a list which translated to a more hull in the water on one tack than the other.
 
30% is a very big difference - I doubt it is weight distribution or that the mast is not quite vertical or straight. It has to be really obvious for that much difference.

Maybe it is actually caused by tide or current?
E.g. leebowing the tide more on one tack than the other?

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Another good guide to setting up the rig can be found on the Selden Masts website

Download the Hints and Advice pdf from HERE
 
Thanks for the pointers.

I had a look at the Kemp guide & one of their first references was to the halyard measurement process, so I will certainly follow that up. I have downloaded the Selden guide previously, but didn't refer to it as I was looking for simple tests and solutions and I guess I expect the Selden stuff to be rather more technical & complex, but now that I've been reminded, I will have another look.

Don't think its weight distribution, tho I did put in a 35l calorifier in the port cockpit locker, so there may be some effect re this, but the tack difference has only really become noticeable in the last yr & the tank has been in 3. Equally not convinced its lee bowing as the last time I noted it, it was beating up the W Solent into a NEly, tho' admittedly with the latter end of an ebb tide.

I guess what I was hoping for was something like "poor starboard tack - set up of port /sboard shroud too loose/overtight or not enough/too little forestay/backstay tension" or some such diagnosis, but as usual, in real life, I guess it is never as simple as that!

Cheers

Rob
 
Interesting point. Hadn't thought of it as a possible reading difference rather than absolute boat speed. It may be in part. It is removed regularly for cleaning, so alignment checked fairly often, but the log impeller is not in the ideal position forard of the keel, instead it is sited on the port side of the keel, 2/3rds aft. Would this set up tend to give give my results? (Average speed on the s/b beat (F3) was c3.5 kts & 4.5 on port tack)

Equally, re Lakesailor's suggestion, tho I do have a couple of separate GPS units (Garmin 128 & 182C Chartplotter), I haven't systematically compared SOG & speed through the water on each tack, so probably aim to do that before fiddling with any rigging set up. However, certainly the impression when sailing is more actual progress on port tack- this even noted by my family crew, who are not experienced sailors and rarely "dial watch"!
 
Any lateral in balance will show up as the boat not sitting level when in still water. Use a spirit level across the top of the transom or cockpit floor.

My boat has always sailed better on port tack hard on the wind. This confirmed after about 20 odd years of racing and has been consistent through 3 masts and rigging replacement. The keel looks straight to me so can only think it is a difference of hull shape.

Check the mast is vertical if so then forget it. olewill
 
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