Mast Step Replacement

[Dale Tanski]

McMaster Carr has stainless lag bolts.

Dale

[PeteW]

Gordon,
Thanks for the feedback.   Here's what I know about my existing mast step. The one in there is 2.8" from floor to the base of the mast. Mine is held in with lag bolts. 3/8 by 5" in 4 places.

Here is a design I'm working on for a solid aluminum replacement. ( see pdf attachment) It' s made from 3 pieces. The base is a 3.5" by 13"x 7.5" aluminum 6061-T651 plate. There are two 1.5" by 7.5" by 4.5" retaining plates. These reattaining plates are cut to fit the for and aft contour of the mast. The get bolted to the base place once the mast is in place. the 4 additional lag bolts hold the entire assembly in place. Other than cutting those curves the whole thing can be made on a drill press.

The plate can be purchased in 3", 3.5" or 4 " plate thickness depending on how much build up you add and how much you cut off the mast.  Keeping a low profile is important as you would not want this step to tip over. You can increase the dimensions a bit width and length if you don't care how much aluminum you will be buying. 6" tall seems like a lot to me. If I build up the floor by 1" you will still need to cut 1.7" off the mast with a 3 1/2" plate material.

I'd definitely glue it down with 5200 prior to bolting.

Pete W.

[Dale Tanski]

Pete,

Great minds think alike...



The curved pieces were cut using a plain old hand hacksaw.  They were then smoothed using a file.  Note the drain grooves to allow rain water to exit the inside of the mast.  These were cut with a ball noise cutter on a Bridgeport mill however you could do it with a router and a carbide fluting cutter making several passes.

You will also note the fore and aft hole.  I added this to install a mast keeper pin/bolt.  I read too much and one hazard when a keel step mast breaks above the deck is the butt end comes out of the base and pivots around underdeck clearing out what ever it comes in contact with.  The pin is designed to maintain the butt ends position in the base where it belongs.  Many offshore races require this little detail in their safety requirements.

Remember that you can also build up the area where the base sits with fiberglass cheaper than making the aluminum bottom plate thicker.  This is actually more desirable as it will provide a flat mounting surface and keep the step high and dry out of any standing water.

Dale

[PeteW]

Dale,
Eerily identical except you have the 3" plate on top. Your design looks to be a  better utilization of aluminum which gets expensive. I'm assuming the mast pin goes clear through the mast. I like that feature and that warrants the thicker retaining plates. Also did you maintain the original lag bolt centers of 10" forward and aft or did you drill new holes in the keel. That scares me because I'm in-the-water. Gold anodized is probably a must do also. I will do the build up with mat-glass-mat-glass etc using epoxy resin.

I do miss my old Bridgeport. Sold that business and all it's cap eq in 1995.  Pete

[Dale Tanski]

Pete,

1) Mast pin/bolt w/nylok nut goes all the way through the mast.
2) Yes and no on the lag bolt centers.  None of my lags came out, all were rotted beyond belief.  I kept the same relative dimensions but did not put the new bolts in the old locations. 
3) Yes on the new drilled holes.
4) Anodizing would have been a great idea but I never thought of it.

Also do not forget to install the threaded hole for the tension rod.

Dale

[PeteW]

Dale,

Regarding tension rod hole. I'm assuming its threaded and 3/8" dia. ( maybe that piece is a bolt ?) If its threaded then the only question left is the thread pitch. I was unable to determine prior to dissably if its  UNF or UNC, 24 or 16 threads per inch. Taping into aluminum I might prefer to install thread inserts for all the bolts.  And it would be nice to start fresh with that stud that connects to the tensioner nut.

Thanks, Pete

[Dale Tanski]

Pete,
It is course just like the nut at the top of the rod in your deck mast collar.
Dale

[PeteW]

Gordon,

Something else to contemplate. Apparently a rigger out here in SOCAL, I will not use his name in case this is bogus, is recommending potting the mast base into the hull a a repair for boats needing a new step. It was described as pouring a footing with some slow cure epoxy to encapsulate the bottom section of the mast. So there is a mold.  Not sure if you can removed the mast after that. But with some release applied I suppose it should be possible. Don't recall what the material was called but could find out.

Pete

[Dale Tanski]

Pete,
If one raises the area outside of the mast, than any water inside the mast from rain has no where to go.  Perhaps the Albert Hammond song "It never rains in Southern California" is true and that is not a problem there.
Dale

[elektron]

Looks like I'm in the same boat...