What are the main factors affecting IC performance?
The IC is a slow boat – a fun boat, but slow. Other than the obvious factors of technique and experience, increasing straight-line boat speed comes down to the essentials. These include (1) boat at minimum weight with lightest possible bow tip weight, (2) combined crew weight not drastically over the minimum (315 lb. dressed), (3) a straight rig (no permanent bends) tuned to the sailmakers settings, (4) a good sail, (5) a relatively stiff and fair hull and (6) good foils. Other factors include the quality of the hardware, centerboard pin position (older boats have the pin further aft) and general layout. There are plenty of sailors out there going very fast in old wood and fiberglass InterClubs with the right gear and set-up.
What is the minimum all-up weight of an IC under national class rules?
250 pounds under national class rules. Larchmont sails at 230 pounds.
My centerboard handle leaks like crazy! My toes are freezing! How can I stop the leak?
See “Sealing your board handle hole“.
Why is it better to move your shroud chainplates forward to near the max forward position?
Moving the chainplates forward allows the boom to be eased further downwind and is faster.
There is some latitude in the rules on where the shroud and forestay tangs can go on a mast. Where should I put the tangs on my mast?
The current thinking is that the shroud and forestay tangs should be as close together as possible. Since all measurements are taken from the centerline of the halyard sheave, the “optimal” locations are 39″ for the forestay tang and 53″ for the shroud tangs. See the rigging and tuning guide for more information.
Can I install a dacron centerboard slot cover?
No. These are illegal by rules interpretation. The CB slot must have an opening of not less than 44 inches long and a width of at least 7/8 inch.
Why do so many older rigs have a small section spliced to the bottom?
It’s mainly because some of the older boats had masts that were too short. They built them too short because O’day would supply a mast step that could be screwed and unscrewed for height depending on how tight they wanted the shrouds to be.So the least expensive way to raise it was to splice a piece in from a broken section.
Is the Dwyer DM-275 mast section legal in the InterClub dinghy?
At present, NO! Only the Zephyr #1 section and the Kenyon B section are legal. Dwyer’s DM-275 section is nearly identical to the Kenyon, having very similar weight and moment characteristics (Kenyon – 0.89 lb/ft, Dwyer – 0.824 lb/ft). The Dwyer is also slightly less expensive (I think about $2/ft). It is unclear to me why this mast section is not allowed under class rules.
What is the bow tip measurement?
The bow tip measurement has been a very controvertial measurement since its inception. It is basically a measurement of the boat’s longitudinal center of gravity. It was observed that InterClubs “light in the bow” performed better in chop. This is witnessed by many people replacing their all-glass bow tanks with lighter cored tanks. The bow tip measurement is a crude but effective measurement that attempts to compensate for light bows by essentially dictatating where corrector weights must be placed in the hull. Limited observations have shown that most boats requiring correctors need them placed at or near the thwart to give the correct bow tip measurement (see class rules for specifics). An initiative is under way to replace the bow tip measurement with a fixed corrector placement rule.
What are typical purchase systems for the IC control lines?
Purchase systems vary in purchase power and arrangement. I like to cascade the purchase whenever possible. This practice minimizes weight, hardware and friction. Most boom vang systems use an 8:1 with a 4:1 cascading to a 2:1. You could also use a 2:1 to a 2:1 to a final 2:1 cascade to get 8:1. I have seen 12:1 vang systems, but I don’t think anything more than an 8:1 is really necessary. Cunningham systems are usually 2:1, but I prefer a 4:1 system to give precise finger-tip control. The forestay purchase should be at least 4:1 and preferably 6:1. The increased purchase puts less tension on the cleat holding the forestay. Under mainsheet tension, the forestay can get to over 300 pounds and I have seen poorly designed 2:1 forestays slip through the cleat. A 6:1 forestay also lets you make fine adjustments more easily. Outhauls are usually 2:1 and I would recommend 2:1 or 3:1.