The following is a simple step-by-step guide to setting your dinghy up. Although all boats are different the same principals apply.
1. It is vital that the mast you will be using is straight before you start working through the measurements. Check that there is no bend fore and aft or side-to-side; if there is bend characteristics will be affected.
2. Most boats will have a position for the mast foot; this is normally measured from the transom. See the Pinnell & Bax tuning sheet. Set this before the mast is stepped.
3 .Set the length and deflection of the spreaders making sure that both sides are equal in length. This refers to the A and B measurements in the Pinnell & Bax tuning guide.
4. Step the mast, hoist the jib up or just the luff wire if a stuff luff jib.
5. With the mast under rig tension as stated in the Pinnell & Bax tuning guide check the straightness of the mast. Is the mast bending to the side?
Are the spreader tips symmetrical to the shroud base of the boat? If not check by placing a string at the shroud base and spreader height. Sight between the two and adjust the spreaders until the two strings are parallel.
Are the shrouds the same length? If not adjust until they are.
On deck stepped masts has the step worn on one side? Is it worth replacing? Will a small piece of Mylar under the mast foot do?
6. The mast should now be straight side-to-side and you can now start to measure the rake and rig tension.
Measuring the rig tension: - refer to you class form on amounts and position of measurement (some classes will measure on the shrouds others on the luff wire). Measure at shoulder height. Check that the wire been used is the same as your tuning guide (dyform will measure a lower reading) Pull until you find the required amount and mark on the mast. It is best to use a Superspar or loos rig gauge to accurately gain this reading.
Measuring rake: - Most classes will have a measurement point from the head of the mast to the top of the gooseneck black band or the gooseneck itself (see diagram below) Once this is achieved swing the tape to the back of the boat and measure at the stated position in the guide (normally at the top or bottom of transom). If the measurement is correct mark this on the shrouds or adjust to suit.
7. With the rake and tension on to the required settings check the pre bend of the mast. To measure this pull your main halyard down to the top of the gooseneck and measure the distance form the aft face of the mast to the halyard. (See diagram 2) This will normally be at spreader height. Adjust until the required spreader deflection is found.
8.Calibrate all your setting so that you will be able to repeat the settings.
9. Check the positions of your jib cars or fairleads. Make sure you can achieve all the settings needed. Adjust if necessary.
10. Go sailing
It is important to check these settings on a regular basis as they may move from time to time. Please call if you require any more help.