Tuning : Inter 17 R

by Mark Biggers, Chris & Mark Batchelor

Starting Point: Hull Alignment

Since all 17s are brand new (out of the box), start with the front crossbeam and set the hulls at the in the saddles & set the bolts ( do not over-tighten). Set the rear beam in the saddle & bolt the rear beam, note there’s no hull align adjustment. The Inter tramps are designed to tension only from the rear beam.

Rudder Alignment

Rudder alignment should be set to 0 or 1/32” toe in to compensate for lash in the rudder system. Measure fore & aft on the rudder, level with the bottom of the stern. The tiller arm to x-bar space should be equal on both starboard & port side… before tightening the set screws.

Daggerboard Tuning

Daggerboards and rudders are the same as those of all Inters so careful tuning is important to prevent cavitations. Rounding of the leading edge seems to be more important than getting the trailing edge sharp. For the trailing edge, thinning of the foil from about 1” forward to an edge about 1/16” thick seems to work best.

Daggerboard Position

Daggerboards should be raised at least 50% for the downwind legs.

Mast Set-up

Set the spreader rake to about a minimum of 1” to 2”, now this depends on skippers weight. Heavier skippers closer to 1” lighter skippers move towards 2”. (Place a straight edge across the tips of the spreaders and measure to the back edge of the mast) it is not important to use a wire tension gage to set the tension of the diamond wires. Just tension the diamond adjuster until you reach appx 1” to 1.5 “ of pre-bend over the length of the mast. Of course final measurement is taken with mast lying on its side.

Rig Set-up

The Inter 17 seems to like a tight rig, unlike other unis, this boat performs better with the tight shrouds. If you’re a serious racer it’s a must to change to the I-17R 1/8 racing rigging. This kit will also include a longer pigtail.

Leveling the boat, & hanging your main halyard, you can measure mast rake. The halyard should touch in the rear half of the tramp. (more rake for lighter skippers).

Downhaul System

The stock downhaul system [8 to 1] is adequate for the all skippers. The leach of the main will open up readily with the application of downhaul. Because it works so well it becomes the sole method of controlling the main on wind gusts.

Spinnaker
Most of the sailors seem to run the spinnakers 4” off the tack fitting & appx. 5” from the mast bail. Also it’s a good idea to upgade the front beam blocks. Add a turning block for the spinnaker halyard off of the rear beam…….Do not raise or drop the spinnaker heading directly down wind!

In Conclusion

The Inter 17R is a high tech around the buoys racer that must be properly tuned to be competitive .We have only begun to tap the speed potential of this great new boat. If you have any questions or comments please feel free to contact Mark Biggers 517-692-9430 [evenings]

Thanks to; Mark & Chris Batchelor for their input…..

Please do not copy this to other Web Pages, but feel free to link to this tuning page





The Cat House..... 517-6929430

Fax-692-9431

Note (4th march 2002) : This is a copy of that web page (the cat house home page is off line)