Mast Step

[CharlieH]

Given a choice between stepping a mast on deck or on the keel, why would an accomplished designer like Crocker ever stick the heal on deck???

[George Roberts]

It removes the mast from the center of the cabin.

[Todd Bradshaw]

It can also make raising and lowering the mast much easier. My Starboat had a long, but pretty light (35 lbs.) mast. It was really whippy and keel stepped. This meant that you couldn't hook up any of the wires until it was down through the hole and in the step. We had to put a boat cushion on deck and one person raised the mast while the other held the butt down on the cushion. Once it was vertical, both people attempted to drop it through the hole and down on the step. You wouldn't believe how much it wobbled around in the process. There were several times where we either just about dropped it in the parking lot or got tossed off the boat trying to hold it. It was an absolute nightmare. My wife did it with me once and said "never again". A much heavier, deck-stepped mast with a well thought out hinge fitting is a piece of cake by comparison.

[Ian McColgin]

There's an entertaining arguement here among off-shore types.

Traditionally keel stepped masts have been favored as the mast is better supported and your more likely to have some rig left after a capsize or such.

However, an acceptably light deck stepped mast can be made - in modern materials only a little heavier than keel stepped - and most rigs will come down if there's an important stay failure anyway, os at least with a deck stepped mastyou don't rip up decking as the rig comes down.

Call 'em as you like 'em.

[CharlieH]

3 good reasons, thanks fellas. I would want to satisfy myself thoroughly that the deck or trunk had some pretty robust deck beams, knees, strappping, etc. in way of the step before feeling comfortable with this arrangement. Imagine compression point loading could be fierce not to mention athwartship pressure as vessel heels.

[Braam Berrub]

Originally posted by George Roberts:
It removes the mast from the center of the cabin.although a lot of deck stepped masts have a compression pole in the cabin to reduce 'pumping' - the deck moving up and down.

Ease of raising and lowering mast, moving the compressionpost offcentre (and reducing the thickness of the post), and not wanting a hole in the deck are the main reasons, iirc.

[Noah]

I suppose that you could argue that if properly designed a deck stepped mast could be structurally stiffer than a keel stepped mast.

On my Hinckley the mast is deck stepped. Underneath there is an I beam running forward about 1.5ft, and back about 2 feet. There are two very stout posts running down to the mast step in the keel, so theoretically the force of the mast is better spread out on the step.

These two posts also act in both tension and compression. This means that the deck won't be allowed to "bow" upwards with the side loading of the shrouds.

Raising a keel stepped mast can be a trick, but taking it back down can be even harder...On my Folkboat the mast probably weights around 150 pounds. Putting it up is tricky, but taking it down means that you have to lift the mast straight up about 5 feet. The stays can't be attached either. It takes 5 guys, and it's still scary.

That said, deck stepped masts without compression posts can really suck.

Noah

[Bruce Hooke]

I knew a fellow who did a major number on his back trying to step his own mast...So all of you who insist on doing the job yourself, especially on a keel stepped mast, be careful out there.

My father's 23' boat has a deck stepped mast and a cabin spanning beam under the mast rather than a post. This basically worked fine (until that beam cracked!) but I'm sure it made the rig less 'tight', making for things like a slacker headstay.

[Mike Field]

These two posts also act in both tension and compression. This is an important point, which I think is sometimes overlooked.

The "compression" post as it's commonly known really acts as a tension member too on occasions. Therefore it should never be just "jammed into place." It needs to be properly fastened to the deck and keel structures so it can stop the deck lifting as well as dropping under dynamic sailing stresses.
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[Dan McCosh]

I'd put in a vote for a keel-stepped mast, mainly because it stands without shrouds while being stepped, once it is set in the mast step. Messing around with shrouds while the mast is unsupported and waving around in the air can be much tougher.

[Bruce Hooke]

Originally posted by Dan McCosh:
I'd put in a vote for a keel-stepped mast, mainly because it stands without shrouds while being stepped, once it is set in the mast step. Messing around with shrouds while the mast is unsupported and waving around in the air can be much tougher.Except that on a deck stepped mast you can often attach the shrouds and either the fore or aft stay BEFORE you start raising the mast, which can make the whole process a LOT easier.