Tuning for North Fisher Nickels (15300 – Present)
Written by Kevin Morin
Below are the tuning steps:
-Move mast butt back one hole.
-Step the mast.
-Lubricate the turn buckles on the uppers and lowers.
-Tension the uppers to 18 Loos PT-1 (240lbs).
-Install fitted block in front of the mast without any other blocks to help make sure the mast is centered at the deck opening.
-Center the rig measuring down to the chine via the spinnaker halyard within 1/8″ side to side.
-Install 2 3/8″ of block behind the mast.
-Tension the lowers to around 24 Loos PT-1 (300lbs).
-Verify that uppers dropped to 17 Loos PT-1 (165lbs) and adjust lowers/uppers to make sure that they are at 24/17 Loos PT-1 respectively.
-Pull a 50′ tape up the main halyard.
-Measure rake with the rig relaxed (i.e. no sails, no backstay, no crew touching it). Should be 26′ 6″. If number is longer (i.e. 26′ 7″), then pull a 1/4″ block from behind the mast and re-tension the lowers/uppers to 24/17 Loos PT-1 respectively. If number is shorter (i.e. 26′ 5″), then insert a 1/4″ block behind the mast and loosen the lowers/uppers to 24/17 Loos PT-1 respectively.
-Record exact rake measurement. ______________
-Attach the backstay.
-Pull on the backstay until the slack is taken out of the forestay. Record the “Change” number. ______________
-The “Change” number should be exactly 3.5″. If it isn’t, release the backstay and adjust the forestay so that the “Change” number becomes 3.5″. If the “Change” number is longer than 3.5″, then make the forestay shorter and re-measure. If the “Change” number is shorter than 3.5″, then make the forestay longer and re-measure.
-Remove the forestay, lay it along the front edge of the mast, and mark the forestay where mast band is on the mast. Attach the forestay and measure from the top of the new mark to the forward most part of the deck. The number should be something like 44 3/8″. However, Greg Fisher suggests, “I’d set it [forestay length] where it needs to be to make the right number at the back [rake]“. So, setting the rake to 26′6″ is more important than the forestay measurement being 44 3/8″. Record the number. ______________
-Snug down the nuts (or equivalent) that prevents the shrouds from adjusting.
-Label all mast blocks with a permanent marker. Label deck so it is clear where each mast block goes.
-If the rig is new, check the tension every race for the first two months because the rig and shrouds stretch.
ADDITIONAL NOTES:
-Lightning Plans and Specifications – > Article 2 – Spars -> 56. Upper and lower shroud tension shall not exceed 113.39925 kg (250 lbs.) with the forestay slack, backstay off and mast blocks removed.
-If the outboard end of the boom appears too high off the deck when heading up wind and trimmed properly, the rake is probably too large. The number should be 26′ 6″.
-If prebend (measured by holding the main halyard taught against the aft edge of the mast and by looking at the gap between the halyard and the mast at the spreaders) is not sufficient (i.e. 2″), the lowers are probably not tight enough. Change the lowers and then go back to step 11.
