When I built my A-class, I did a bit of research on rudders and daggerboard profiles. One of the things that I came across was an article by Martin Fischer on the DAG rudder profile that he had designed that has a hollow trailing edge. This provides a reduction on drag by allowing the rudder to pull less water along behind it. He had data on how much less drag it produced compared to a NACA 64 series board which is a good design already. The website was for a Mikan A-Class and is now defunct, but most of the A-cat designers are using the DAG profile. If your 44 series profile were to be made symetrical, it would resemble the 64 series design.

As his Dag rudder profile was proprietary, and unavailable, I aquired an Eppler assymetric foil shape set of coordinates that featured a hollow trailing edge, and made a symmetric set of coordinates from them, and then used those coordinates to build the foils. To make them work well, you have to work hard to get the trailing edge very fine, and then they are fragile. It is real hard to get the foil exactly right. The first set I made were too thick in both the leading edge and trailing edge.

The reference I followed for the planform was a text by model aircraft builders that state that an elliptical shape is best. The trailing edge should be straight, andt hen the front should be straight for about half the legnth, then start to taper, and then the end should be rounded off to a 90 degree angle with the trailing edge. Alternately, a taper with a rounded end is almost as good. That is what Marstom boats use if you can find a picture of the foils on one of those A-Cats.

I made my rudders at just under 10% thickness to chord. The daggerboards were made at about 8% of the chord thickness. It took a while to make a decent plug of the correct thickness. After 4 trys, I finally made a square ended daggerboard plug by laminating cedar together wide enough on plate glass glued on a frame, then shaping it with a 3 inch wide wood block that had been routed to the correct shape and using a jig to keep everything straight. Then I overlaid it with one very thin layer of 3 oz fiberglass cloth, and then sanded it fair using the same block to get close to the correct foil shape. I made the mold by laying several layers of fiberglass over this with plywood edging. So my daggerboards wind up being straight with a square bottom. If I were to do it again, I would make them the tapered design.

It is not even close to easy to make a real good foil. The suggestion to get a mold made for you by Phils Foils or some other shop with a computerised shaper is a very good idea. You will then get a perfect foil shape and be able to replicate foils over and over. One other thing to consider when making your own foils is that it is esy to make them too flimsy. I have broken both original rudders and one daggerboard so far. So as the first daggerboards proved too short in light air, I made 2 new ones. The second pair of daggerboards are noticeably better than the first ones, as I took more care to ensure the daggerboard halves were not too fat at the leading and trailing edge.

I hope this helps.