Technical & Equipment from Ocean Sailor Magazine

For a blue water yacht, which is best, a keel or deck-stepped mast?

For a blue water yacht, which is best, a keel or deck-stepped mast?

From a safety perspective it will always be better to have a keel -stepped mast. Dismasting is arguably the sixth worst hazard a sailor faces, after keel loss, rudder failure, gas explosion, fire, and man overboard.

The principles are self-evident. With a keel-stepped mast the foot is sat on the keel and locked into position and then locked again as it comes through the deck.

Whereas a deck-stepped mast is only supported, but not necessarily even locked in, at the base on deck.

If one element of the rigging breaks on a deck-stepped mast , especially the forestay or backstay, the stability of the mast is seriously compromised with nothing to stop it collapsing forward or aft except the shrouds, which are mostly loaded athwartships. When rigging fails on a keel -stepped mast there is still the bracing support between the keel step and the deck collar to hold it up.

When a yacht is banging into a powerful head sea, the mast is flexed out of shape as it pumps, which will cause the rigging to slacken on each pump. (Beside)

If the pumping action creates a big curve the mast can actually  jump out of the deck collar on a deck-stepped mast. 

A keel-stepped mast will pump less violently because it is supported at the deck collar.

So why do many modern yachts have a deck-stepped mast?

Firstly it’s cheaper because the mast section is shorter, secondly the cabling for the mast equipment, is cheaper too, because there’s less of it, and thirdly it is more convenient to run the cabling out of the bottom of the mast straight into the cavity between the deck and the deck head.

Another reason is aesthetics: the mast section inside the vessel below deck restricts interior design, which, of course, should never take priority over seaworthiness. 

A keel -stepped mast is more expensive than a deck-stepped mast this will reflect in the cost of the yacht.

The customer has to ask himself if it’s a price worth paying.

We at Kraken Yachts answer: ‘Most definitely!’

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