Where To Put Your Mast
by Joe Whitwell
You will have noticed that our modern rigs and sails need to have their masts placed much further forward in the boat than of yore. I think the reasons for this is that we are using so much stiffer masts and sails with much tighter leeches. To quote the old maestro Paul Elvstrom:
'If the mainsail has a very hard leech, then the dingy will carry a great deal of weather helm as the wind increases and to prevent this you must move the mast nine inches further forward.'
Don O'Donnell has now kindly supplied me with the figures for the mast position that he is using on his boats, and this includes the World Champions boats. Both the heel and deck bearings are adjustable so that you can alter the rake to suit the wind conditions and make fine adjustments to the balance of your boat and the figures given are the positions of the hearings in their most forward positions.
Measuring from the stem to the front edge of the bearing hole of the deck bearing, the minimum distance is 648mm (against the 'standard' 800mm for the old wooden masts).
For the heel bearing, we measure from the number 3 bulkhead to the front edge of the hole and this is max. 630mm. If you have a boat with no station 3 bulkhead, measure from the station 2 bulkhead and make it 1630mm.
If you have an old wooden boat, you will have to cut your stem piece right back and fit in a new keel bolt to get the heel bearing this far forward. So take care that the whole stem does not fall apart and is adequately strengthened.
If you can not get the mast far enough forward, there is no alternative but to go for a different rig. To quote again from Elvstrom:
... but the weather helm can also he corrected with a new sail, which does not have a hard leech, instead of moving the mast.
If you have a bulkhead between the mast and the centreboard case, it may not be at Station 3. Check the distance from the transom, 2800mm, if you want to use this as a datum point for the position of the bottom mast step.