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Traditional Nauticat Door Roller Replacement

Category: Hull

Contributed by Chris Woodbury

Summary: All of the Traditional Nauticats (Woodies) have sliding hatches (doors), which ride on rollers. These rollers fail after a few years because they are made with carbon steel and soft plastic. I have designed a replacement which is not too hard to build and will last longer.

Replacements are also available from Nauticat Yachts OY in Finland. Email sami.louhelainen@nauticat.com.

The carriers are made of 16 ga brass cut out of sheet material. 5 rollers can be made from a piece 6" X 4 ½" with not too much waste. I cut them out with a jeweler's saw obtainable from hobby shops. First spray the sheet metal with a flat gray paint to make it easy to draw the layout on the sheet. Once cut out and filed clean the bending process is done in a vice with a piece of steel ¾" by 1 ¼" and about 3" long. The first bend is done between the jaws of the vice making sure the bend line is just above the edge of the vice. The second bend is made with the piece of steel held tight against the first bend. I use a second piece of steel to start the bend close to the vice jaws. This makes a sharper bend.

The wheels are cut out on a lathe and drilled for the 3/16" shaft. The material for these is a UHMW (ultra high molecular weight) polypropylene plastic, which is a dense low friction plastic. I find it lasts well in this application. This material comes from an industrial plastics supplier and is not expensive but must be purchased in minimum quantity. 12' of round stock 1 5/16" dia. for about $32 will make over 200 wheels. Contact me and I will make the wheels for you. In either case, make the wheels just a little narrower than the grove they will be riding in. Usually they are 9/16" but for the NC36 they need to be 7/16" wide.

Shafts are made from 3/16" brass rod that can be found in any good hardware. I cut it on the lathe but a hacksaw and vice are adequate. Wrap it in cardboard to prevent scoring the surface. File off the cut ends to the appropriate length so that peening will be even.

diagram

The next step is to drill the holes for the shaft in the right places on the carrier. This has to be done accurately or the wheels will run crooked. I use a divider to scribe a line up the center of each side of the bent up carrier (using a square) and another line the correct distance up the side. With the carrier sitting on a flat surface, use the divider to scribe a line at the correct height for your boat. For most Woodies it should be ¾". Now use a punch to dimple the metal to start the drill. Drill the first side against a block of wood held in a drill press vice.

The second hole needs to be aimed, checked and punched through the first hole. A nail-set ground to a point works well for this. If the holes end up out of line I use a jewelers file to skew the holes just enough to correct the alignment. Just a touch with a tapered reamer will open the hole for a good fit on the shaft. A good fit will mean that the shaft will only have to be peened a little to secure it. Peen over the ends of the shaft against the flat of the vice just enough to assure that it is firm.

I always forget to drill the mounting holes until after the wheels are assembled. Hold the assembly in a drill press vice and against a block of wood and drill these holes to match the old units removed from the doors.<br />Good Boat keeping,<br />Chris

See an enlarged diagram: ~/tips/images/doorwheels.jpg