Bournville Yacht Racing
Radio Control and Free Sailing yacht Racing
A part of the Bournville Radio Sailing and Model Boat Club
A few hints on rig preparation and sail setup:
Everyone prepares and sets up their yachts differently but there are a few guidelines worth remembering:
Ensure you mast is upright, there are a couple of ways to do this :-
The best being in a tank, setting up your mast this way enables you to have a constant – you can always go back to square one if things are not going well!
Alternatively ease the mainsheet to a running (fully out state) and flick the main boom from one gybe to the other, assess the “lift” at the end of the main boom this should be equal on both gybes with a similar lift amidships.
A point identified above is the lift being the same when fully sheeted out as it is with the boom on the centreline – this sounds easy however, with most yachts having the mast raked towards the stern along with an amount of curvature in the luff of the mainsail can make this a difficult thing to achieve. The effect of rake and luff round significantly changes the geometry of the sail and gooseneck / kicking strap arrangement having the effect of either tightening or loosening the leach of sail for different points of sail.
The next thing to consider, as a result of the round cut into the luff of Mainsails when the mainsail is sheeted out the tension on the luff increases this is detrimental to sail set, to overcome this a number of methods for automatically releasing luff tension using a Cunningham have been tried – a good source of information on these is via Lester Gilbert’s website -
Well worth a look…
As we have discussed earlier luff round has a significant effect on your rig setup and requires you to fine tune the loading of forestay, back stay and mast ram (if you use one) to set the shape of the mast to fit the sail – really a trial and error as every mast, sail and boat are different, the thing to remember her is the sail maker has designed his sail cut for a reason and your setup needs to be in line with his thoughts..
Once you have achieved a good setup with enough forestay tension to stop the jib from ‘flapping’ when under load you can fine tune the shape of the sail with backstay, Cunningham and kicking strap tension
A few examples can be found on the North Sails website although targeted at full size the principles and effects are the same
Also an article from the Guildford website on air flow and sail setup is well worth a look
also checkout Lester’s interpretation of telltales on sails and what the mean…
There are a number of ways to overcome this issue the simplest and cheapest is to “jack” the bottom of the gooseneck fitting away from the mast to change the geometry – it only requires a small amount of change to have a significant effect.
An example of a shimmed gooseneck by Lester Gilbert is shown to the right.
It should be notes the shim angle needs to change if you alter the rake of the mast!
Dave Potter has developed a gooseneck arrangement that easily enables the axis to be altered by fine tuning a single screw
simple to alter but like all things you need to remember to check and alter if you change the basic setup of the rig.