Fabricating a Steel Ballast Keel Box for a Boat Build

|Peter Johnson
Fabricating a steel ballast keel box

Building the ballast keel box

We've reached the point where we need to make up the ballast keel box.

The box is being built from 22mm mild steel, with stringers cut from 60mm plate. Each stringer needs drilling and tapping with 22mm holes. Once the box is assembled, we'll fill the voids inside with cement and lead.

Fixing the box to the hull

The box will be held to the boat with 18 mild steel studs, each wrapped in PTFE tape and lithium-based water pump grease to prevent seizing and corrosion.

Total ballast weight will come to 5,000 kilos.

Next: sheathing the hull

In the meantime, we're preparing the hull ready for a covering of bi-axial glass cloth and epoxy resin. Keep an eye out for updates on this next stage.
Peter Johnson

Written by

Peter Johnson

Pete Johnson is the owner of Epoxy Ltd, trading since the late 1990s and supplying MAS epoxy and boatbuilding materials to professional and DIY builders alike, all under the philosophy of "Simple Perfection". When he's not helping customers, he's usually elbow-deep in one of his own projects, from building the 38ft schooner Iracunda from scratch to restoring boats like Junior, a 1950s Yachting Monthly dinghy rescued from the scrap heap. He writes the workshop blog to share the practical, often hard-won lessons learned building and repairing boats with epoxy.