Independent guide: Whether your mast is keel- or deck-stepped is set by the designer. Do not change it without professional advice.

Quick answer

A keel-stepped mast passes through the deck and sits on a step on the keel or floor, with wedges or a collar at the deck partners. A deck-stepped mast sits in a shoe on deck, with a compression post or bulkhead below carrying the load. Keel-stepped masts are stiffer and more robust after a stay failure; deck-stepped masts are simpler, drier and easier to lower. Each has its own inspection points.

Comparison

Keel-stepped Deck-stepped
Support Deck partners and keel step Deck shoe and compression post
Stiffness Higher Lower
After a stay failure More likely to stay partly standing More likely to fall
Leaks At the mast boot Rarely
Lowering Needs a crane Can use a tabernacle on small boats
Typical on Many monohull cruisers and racers Catamarans, trailer sailers, many production cruisers

What to inspect

Keel-stepped: the mast step and heel for corrosion, the partners and wedges, the mast boot, and wiring where it exits the mast.

Deck-stepped: the deck shoe, the compression post and its base, deck cracking or sagging around the step, and bulkhead doors that stick.

See mast step and compression structure.

Frequently asked questions

Is a keel-stepped mast better than a deck-stepped mast?

Neither is universally better. A keel-stepped mast is supported at the deck and the keel, so it is stiffer and more likely to remain partly standing after a rigging failure. A deck-stepped mast is simpler, keeps water out of the cabin and is easier to lower. The right choice depends on the boat's design and use.

Why does my keel-stepped mast leak?

Water enters around the mast boot or collar at the deck partners and can run down the mast inside the cabin. A failed boot, poor sealing or missing wedges are common causes. The mast step at the bottom can also collect water and corrode.