I was asked to give a presentation of this topic at the annual meeting. After a lot of whimpering and whining had excused me, I was asked " well what about an article? ". at that I conceded.

What I would like to present is a simple method to take an existing boat and tune it for speed. this method will concentrate on the most important aspects of tuning which although they are labor intensive, they are not expensive. what is really important is where the steel meets the ice. this means the shape of the cutting edges, their surface finish, their straightness, and t alignment of the side runners.

Straightening runners - This method works with Sarns runners and with other plate runners which are heat treated only at the lower edge. It will also work for insert runners which are stiffened with steel or aluminum on t outside. Do not use this method to bend through-hardened steel plate or the inserts themselves. The assembled runner with external metal stiffeners - yes, the individual heat treated inserts - no.

Using a 18" (minimum) machinist’s rule, check the runner at the stiffener, and just above the ground edge. Rock the rule looking for high spots, which are marked at teach end. Using wood blocks, a strongback such as a thick plank or workbench, and a heavy duty 8" C-clamp bend the runner at the center of each high spot. the bending is done in increments of 1/64th" as measured with a 6" machinist’s rule. bend to 1/64Th", recheck, bend to 264th, recheck et., until finally the high spot is eliminated. Straighten all runners to within about 1/64th" in an 18" span.

Sharpening runners The base method uses a 26" long sanding machine inclined at 45 degrees. This allows the runner to be swept through an arc as it is sharpened which achieves a straight cutting edge with a gradual camber. Whatever method is used, the goal is to form a straight edge of about 90 degrees with a smooth camber, free of abrupt changes or knuckles. The camber should be 1/8" above the ice in front and 1/16" about in back. the back 2-3" of the runner should be dulled and rounded up in back so that rough ice will not cause the runner to dig at the rear. Some also retreat the leading edge of the runner similarly however the dulling is done to a lesser extent. The runner should be relatively flat under the pivot pin, which is checked by viewing the gap between the runner and a backlighted straightedge. Shims of .008" thickness are slid between the edge and the straightedge and the distance of the shims is recorded.

The length of the true flat and the length of the .008: flat is used as comparative tool. The last step is to rock the straight edge (or runner) in order to detect any knuckles. Any found must be removed. All checks must be made with the runner at room temperature. Cool the runner after grinding and preferable wait a few hours before making a final measurements. This is extremely important, and it is something that I learned the hard way after runners that I thought were perfect turned out to be very slow. After the runner checks out, lightly stone each ground surface using a small medium or fine grit whetstone or Arkansas stone. If you cannot detect any burrs when you run a fingernail down the runner then it is done.

The optimum runner measurements vary for both types of runners, as well as for wind and ice conditions. A good general use profile for plate runners is 3-4" of flat with 15-17" of .008" flat. Insert plate runners can use 4-5" and 20". Steering runners work well at 2" and 13" More camber and less true flat is fast in light air and for maneuvering on small courses but the side runners dig in to much as the wind comes up and flatter runners are required. Maximum flat is about 5" and 20" for plates and 8" and 24" for inserts, however, these are special profiles and you will require the general purpose profile for each. This also allows the side runners to be used as spare steering runners ( you must drill a hole and make a parking brake however).

One more measurement of runner straightness should be made. This method also determines runner edge alignment to the chock which is necessary to be able to switch runners without altering the side runner alignment. Mount a small inexpensive 4x gun sight to a wood or aluminum block (1/2" by 1/2 by 4" long). Cut a "v" groove that is slightly wider angle than the runner angle and is aligned with the axis of the scope. Use a rigid vice or better yet, a chock mounted upside down on a bench. Mount a section of yardstick on a wall about 30’ away at the same heiht as the scope will sit on runner. Straightness is checked by observing the shift of the cross hairs as the scope is moved along the cutting edge. Movement of less than 1/8" is excellent, 1/4" is probably acceptable, and 3/8" is probably marginal for longer flatter runners ( all measurement at 30’). Move the scope back to the pivot pin and note the reading on the ruler. Mark this value down on the runner somewhere, since we will use it for the alignment, and for interchanging runners. This variable is only controlled by the technique and the equipment used to sharpen the runners. A rigid long flat sanding machine, which is relatively free of vibration and which aligns the runner consistently in the chock area is required. The runner must be smoothly swept through the grinding and must be kept cool. As the technique is applied, the runner’s straightness improves over several sharpening cycles.

Side Runner Alignment This method uses the same gun sight we used for runner straightness checks. It is an optical alignment method which is extremely accurate, as long as we are careful to eliminate all variable that introduce errors into the method. First mark the runners port and starboard; as we found above, they rarely will point to the same mark on the wall ruler. It is best to use two runners that sight to the same mark on the wall ruler or at least to within 1/16" in 30’. Glue both chocks to the plank during the procedure. They are easily removed by moderate heat (about 300 degrees), and you know that the alignment will not drift. Minor changes can still be made by shimming runners and by swapping sides or sets. Prepare the plank and the chock for gluing by drilling a pattern of 1/2" holes 1/8" deep in both surfaces. This allows a mechanical lock of the assembly which does not rely on an adhesive bond to aluminum. If you are still opposed to gluing both at least glue one chock. the other chock can be locked if a sheet of 80 grit sandpaper is glued grit side down to the underside of the plank. The grit locks into the aluminum but still allows adjustments to be made. Drill five of the six holes oversize to allow slight rotation of the chock about the remaining hole. Perform a dry run of the alignment procedure. At this point verify that the runners are vertical when the boat is loaded (see below) , and correct as necessary. When ready, assemble the chock with holes filled with thickened epoxy, perform the final alignment, and gradually and carefully torque the fasteners.

The first chock should be glued and allowed to fully cure before proceeding. It’s alignment perpendicular to the length of the plank is important but slight error is not critical. I set this using a framing square held on the chock / runner. A wire is stretched from the pivot bolt, across the runner to the pivot bolt of the opposite runner. The square is aligned to the wire. The method gives reasonable accuracy. - If you have a better procedure I would be interested.

The alignment must be done with the plank deflected exactly as it will be on the ice. This means full weight of the boat, rig, and skipper as well as the expected downward load for light air which is about 20 lb. The angle of the runners to the ice is accounted for by rigging the weighted boat with all three runners and locking this setting by tightening the side runner bolts. Make sure that one side runner is free to splay out as the boat is loaded - use 1/8" dowels or balls from bearings. The resulting deflections measured and then locked by lashing the side shrouds together about the 2’above the plank. Ensure that the lashing has not slipped by checking the deflection measurement just before the final alignment. Alternate loading procedures can be used ( the above is the easiest by far) but be aware that if the boat is supported inboard of the chocks then considerably more weight is required to achieve the normal sailing deflection.

Block the boat above the ground a uniform distance fore and aft. This distance must allow comfortable viewing of the scope when held on the cutting edges of the runners. With an assistant, accurately mark the runner cut on a 1" x 1" x 9’ stick held under the pivot pins. Highlight the outside edge of this mark with a black marker - The scope can then sight the edge of the mark, which is more accurate than sighting the center of the mark.

This target stick is then moved out in front of the boat a distance of 40’ minimum - 100’ or more is optimum. It must be supported at the same height as the scope. Use a framing square held at one mark to both align the target perpendicular to the boat. Next slide the target laterally until the square points directly at the edge of the fixed chock’s runner. Ensure that the target remains perpendicular to the boat. go back to the boat and sight the target using the scope on the fixed runner. Shift the target laterally until the fixed runner is perfectly aligned to it’s target mark. sight the loose chock to its target as a dry run and if OK, assemble the chock with thickened epoxy and perform the final alignment. Torque the fasteners and resight both runners as a final check.

Checking alignment on the Ice This method quickly and very accurately measures the alignment on the ice. It is not recommended for gluing chocks due to temperature problems, but if one chock is loose it can be easily adjusted. make a fixture using 12" x 18" piece of plywood. Mount a grooved piece similar to the piece used on the scope lengthwise on the plywood. Mount a 2" length of 1" x 1" on the scope lengthwise on the plywood. Mount a 2" length of 1" x 1" angle iron so that it is not loose but can still be rotated horizontally. to this piece vertically mount a 1/4" x 1" x 16" piece of aluminum or similar shaped rigid material. At the top of this piece fasten the scope so that it can be rotated vertically but is not loose. Wingnuts are useful for these connections. The fixture can be used under each runner without altering the scope’s position on the fixture.

To use this method on the ice, rig, weight, and lash the shrouds as before. Find a house on the distant shore which is as far away as possible but at least 1/2 mile. Point the boat toward the house and place the fixture under one runner - say port. Observe the house through the scope and pick windows, doors or other clearly recognizable features that are approximately 8’ apart. Carefully lift the boat off the fixture and set the boat down gently. Then carefully lift the starboard runner, place the fixture under it and carefully lower the boat until the runner sets into the groove on the fixture. sight the right side of the 9’ distance and estimate the misalignment if any. Check by carefully returning the fixture to the port side and ensuring that the scope still points to the selected object. The procedure requires only a few dry runs to achieve repeatability. Although, the method appears inaccurate, an estimation error on 22’ on an 8’ width at 1 mile is slightly over 1/8? misalignment in 30’, which is acceptable. Accuracy of estimation 8’ at 1 mile using windows is much easier than it seems. Corrections can be made on the ice by shimming or swapping runners. If the distance can be determined by a map, and the 8’ estimate is accurate then you can calculate the actual toe-in or toe-out at the 30’ runner sighting distance. This toe in/out value is marked on the plank and is used when swapping runner sets. Shim tape is used on the inner (stiffer) side of the chock. It is available in .007" and .012" thickness. This is about 1/4" and 1/2" corrections at 30’.

These procedures must be done before investing in higher grade equipment, or the added expense will not produce the expected speed improvements. But an immediate performance increase will result if the above steps identify and correct any problems. As I said before this will allow you to make an existing boat fast! To make it really fast, we have to ask Jeff. Maybe he will write part II.