Rebuilding a Mast Step
On a 30 Foot MK I

by Andrew R. White


My approach to rebuilding the mast step is probably overkill, but I know it will olutlast me and I won't have to worry about it sagging. The total cost in supplies is approximately $100-$120 depending on your supply of tools, etc.

The supports are made out of 1/4"GP03 fiberglass boards laminated to the original step thickness.

First, measure and mark where the original mast step is. Use the gap between the cabin sole and the top of the supports for reference.

A reciprocating saw will come in extremely handy for removing the mast step. If the tabbing and supports are rotted enough, make two simple cuts down the middle of the supports in the shape of a "V". Once you have made the cuts, you can take each support out in three pieces. Underneath the support is some epoxy putty that will generally remain intact. Leave the putty in place to use as the new base. The old tabbing can be ground off with a "Dremel" tool or simply pulled off. In some cases, the tabbing is not wetted out very well so it will peel off in most places.

Once all the tabbing has been removed, the areas that will be used as gluing surfaces should be cleaned with acetone and roughened up.

Take the old step pieces and place them on plywood to trace out templates. Once you have the templates that fit they can be used to make the fiberglass boards. You need a piece of GP03 fiberglass board approximately 4'x3'. This is available from your local plastics suppler for about $65.00. This is a polyester resin based board. The bow and stern supports are made out of 6 pieces each making a thickness of 1 1/2". The middle support is made from 8 pieces for a thickness of 2". Laminate the boards at home and sand smooth the gluing surfaces and top surface if any glue oozed out during the process. As seen in the photo below, stainless through bolts have been added for extra strength but are probably not needed. The supports can be made a few inches wider that the sole opening since you can drop and twist them into position. Install them in this order -- bow, stern then middle.

Use West System exposy with the high compression filler for gluing them into position. The filler will work out nice to fill any voids in the original putty job. Once glued into position, tab them about three times each side.

Plane the bottom of the wooden plate that the aluminum casting sits on. Then laminate a piece of oak to the bottom to make up the difference. In some cases, the board may be soft on the bottom side only, so a total relacement may not be necessary. Use the wooden board as a template for drilling the holes into the new step. Drill and tap for 1/4"x20 screws directly into the fiberglass supports. This should provide all the strength needed. If the threads strip, epoxy in threaded inserts.