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There have been some good responses to this question in an early topic on this forum which should be required reading.
The consensus is that extreme forward or aft mast step position makes no difference as long as the rake used gives balance, the more forward the mast step the more rake is required.
If you are using rake measured in actual terms from the black band, it is critical to have the boat set up in the fore and aft sailing position- rather tedious. It is more practical to measure black band to transom. While it varies from dinghy to dinghy due to slight differences in shape, for an individual dinghy it is a precise measuring distance easily measured.
Having just acquired a Sabre, I tested out different mast step positions and adjusted the rack for balance in 8-10 knots of breeze. I used 266 and tested four sails, each had a different required rake for a mast step position. This was due to different sail shapes and mainsheet tensions to get the tuffs flowing.
To make life more interesting, there are of course numerous reasons why the optimal rake will vary. Just a few are fresh/salt water, weight of crew, flat/choppy or swell conditions, design of boat-mainly rocker etc..
My conclusion was that with more rake you could centre the boom marginally more in light-medium conditions, possibly a slight advantage. However, I ended up with the furthest aft position being better for me. The reason, I am tall, heavy, and old thus the more room to duck under the boom while tacking the better!
If the dinghy is balanced it will be potentially fast, the rest is cosmetic.
Thanks for the information Phillip.
I am trying to make certain my Sabre fits the rules. I am refitting 982 and so far have found several mast and boom measurements to be way out. For example, the boom vang measurement is 100mm short while it has a wire strop rather than a towel rail. My next task is to refit 266 which is really neglected with spots of rot which I will West System.
Fortunately one of my friends currently sailing a 2.4 in the World Ckampionship in Sweden, is helping me. He is an ISAF measurement expert and did it for the Mirror Worlds in Tasmania
Regads, Paul
Thanks for your response. I will take the suggestion and go with foredeck location using Ronstan small cleats.
Phillip should be congratulated on his excellent resposes to this and the similar question on mast step position.
A general agreement, but not proven, is a dinghy goes to windward better when it carries a degree of mast rake. A typical rake if applied to a Sabre would be about 200mm measured at the gooseneck from a vertical line to the black band when the waterline is level.
As Phililip says there should be a slight weatherhelm going to windward, say about 3-5 degrees. Thus, in theory the mast step position should be varied such that the weather helm is optimal when there is some 200mm of rake.
There is also general agreement that forward rake is best for downwind sailing. The Sabre can not alter its mast rake while sailing, so it has to be a compomise decided by what the skipper hopes to achieve, for example fast first beat to get out of the pack, as against better marginal planning if you are a light weight.
In practice, most people first decide on where to fit the mast step[subjective decision] then find the best rake by trial and error to get the best helm characteristics[cbjective decision]. The rake which gives the best balance will vary by dinghy shape, sail characteristics, skipper’s skiill and also weight. For example, a heavy skipper will need to sit further forward to stop the tuck dragging, and thus need slightly more rake. The rake would also need yo be changed for fresh or salty water.
My suggestion is fit the mast step according to fashion but work hard to find the best rake for that setting. It seems a wide range of mast step settings with the correct rake all give similar good speed. Using the wrong rake for the chosen position is the quickest way to the back of the fleet due to the most effective brake on a dinghy- the rudder!
A possible limit to changing the existing mast base position is the distance to the shrouds to remain in the measurement rules.
I am just refitting a derelict Sabre hull for mainly social sailing, my first dinghy sailing for 40 years, and my choice of mast step position was decided on by reference to Rule 86. Where the halyard lock could legally go without cutting the existing wire!
