Mast Floats: the $40 Insurance Policy

Text and illustration Stu Whitcomb

Most of us have read at least one article dealing with turning turtle and risking hypothermia. In nearly 70 years of sailing, I have been fortunate to have escaped that trauma. However, the odds were narrowing every time I sailed my 15-foot cat-ketch.

With that in mind, I added floats to the tops of my masts. They certainly didn’t enhance the beauty of the boat, but they did increase my confidence, knowing that turning turtle would be far less probable.

Mast floats are not new and can be purchased as three basic types: rigid closed cell foam buoys mounted to the mast head, soft closed cell foam padding sewn into the upper portion of the mainsail or inflatable packs that can be attached to the mast near the top.

I used rigid closed cell foam lobster buoys to make very affordable mast floats. These floats with hose clamps cost less than $40 each.

Materials for (1) mast float:

• Float: Rigid Foam Lobster Buoy

• Shaft: PVC Lobster Buoy Spindle

• Float to Shaft retainer: Buoy spindle washer and cotter pin.

Shaft to Mast mounting:

• Option A: Boats with no standing rigging, external sail tracks or require a sail lashing technique; mount the shaft to the front of the mast; use (2) stainless hose clamps

• Option B: Boats with a headstay and internal sail tracks (sail slide groove), mount the shaft to the side of the mast; use (3) through bolts and lock nuts.

Before beginning your project, take your boat into shallow water and intentionally capsize it, with a medium size fender attached to the masthead and the sails up. Study how it floats while it’s in the 90-degree knockdown position. There will be variables that may affect your test: wind and waves, crew/gear weight and placement, the amount of water that floods into the hull and how much resistance the soggy sails offer when recovering from the capsize.

Now, let’s calculate the size of a mast float. Think of the mast as a long lever. The float and the mast work together to provide the buoyancy. If the float has 10 pounds of buoyancy and the mast is 15 feet long (10 x 15=150 lbs of lift). In this example, two equal size masts, with floats, have a total lift of 300lbs. Not bad!

If you don’t wish to buy commercially available mast floats, you can make your own, as illustrated here. Go to lobstering supplies at: hamiltonmarine.com and start making your sailboat more safe. •SCA•

Stu Whitcomb has been messing about in sailboats since he was eight. Sixty years later he still has found no cure. Before retiring, Stu was an industrial designer and a yacht broker.

First appeared in issue #98