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smallyachts · 06-05-2010, 17:32

The mizzen mast step on Sam McGee is now squished to the thickness of cardboard, so I suppose the time has come to replace it. I do not want to drop the mast if at all possible. The boat is a 39' C - Farer and I suppose the aft mast is probably 37' give or take. I estimate I have about 3" of expansion left in the turnbuckles.

My plan is to lay a 6x6 Pressure treated post athwartships fore and aft of the mast, resting on the raised bulwards which are about 15" higher than the mast step.

With these posts secured to prevent movement either side to side as well as fore and aft. Then a short piece of 2 x 6 on each side of the mast both on top and on the bottom of the athwartship posts. This should create a very stable collared area to contain the base of the mast from any unwanted lateral movements.

I plan to cut out the profile of the mast in a couple of pieces of 2" thick cypress to use as a clamp around the mast about 18" above the athwartship posts mentioned earlier.

Then I plan to loosen each of the shrouds for the mizzen a 1/2 turn or so and use a small hydraulic jack between the collar around the mast and the posts to lift it in small increments, jack, loosen, jack, loosen etc...

After raising the mast a couple of inches I should be able to cut out the forward cockpit seat / mast step plywood piece, slide the precut/pre-fiberglassed new plywood piece to replace the forward cockpit seat / mast step piece in and secure it in place.

Reverse the process by tightening the turnbuckles 1/2 turn at a time, and throttle the release of the hydraulic jack to slowly set the mast back down onto the new mast step.

Thoughts and suggestions appreciated.

**sarafina** · 06-05-2010, 17:36

wow. you got big brass ones!! 8 - O

that sounds like such a balancing act! be really careful of your fingers, ok?

Sailmonkey · 06-05-2010, 18:28

Uggg...all that work to put plywood back?!?!?!?!

Surely you can find something better like some FR4 or something similar

http://www.plasticsintl.com/datashee...ic_G10_FR4.pdf

I think with a compressive strength of 55,000 lbs it should do the trick

tager · 10-05-2010, 16:40

Sounds like it would work. People raise houses this way so it should work with a mast. Just make sure your collars are overbuilt.

Stillraining · 10-05-2010, 17:20

I don't see and issue either...but I agree with using something other then wood....I went with SS and Derlin

Laidback · 10-05-2010, 17:43

" MY plan is to lay a 6x6 Pressure treated post athwartships fore and aft of the mast, resting on the raised bulwards which are about 15" higher than the mast step."

Hard to understand the above - it seems to read ' Two 6" x 6" beams , one either side of the Mizzen post laid horizontally from one side of the boat to the other, resting on the bulwarks'

How about a photo or a sketch of the present mast step? Does the base of the mast rest on a step on the deck? And/or is there a compression post between the deck and the keel?

senormechanico · 10-05-2010, 19:25

It ought to work fine. Imho, it's even a little over kill.
The mast doesn't weigh that much.
I jacked my 46' mast up about an inch to be able to slip in the bottom fitting for a boomkicker, and didn't use any lateral preventers, although I was able to see the square post in the mast socket. I just eased the rig, used a hydraulic jack and a 2x4 cut to length to push up on a mast ring used for halyard storage. Worked great.

smallyachts · 12-05-2010, 17:33

I have attached an image that shows the existing mast step area. SailMonkey,I agree and have decided to build up the forward cockpit seat / mast step up out of a composite polyester material, instead of using marine plywood. Although the previous step has lasted over 24 years.

The image shows one side of the bulwarks that will support the two beams.

Underneath the plywood that the mast sits on is a steel plate that is connected to the hull via 3" angle iron that creates a very stable platform.

It looks a lot rougher than it is, the vertical components in the cockpit are all solid, all of the horizontal components are soft. However I will feel alot better when everything that is sat on, stood on, or stepped on is replaced.

DeepFrz · 12-05-2010, 17:40

I really would recommend that you unstep the mast. It shouldn't be that big of a job and then it will be out of the way while you work on the area. You are not just replacing the mast step but all the surrounding area as well and I think you will find that the mast will be in your way while you work. This doesn't look like a trivial job.

I would also recommend that you raise the area that the mast rests on so that you have better drainage from around the base of the mast.

smallyachts · 24-05-2010, 07:34

Just an update on the status of our in situ mast step replacement.

Our lifting rig worked exactly as I had hoped that it would. We were able to get a total of 3" of lift. We found a poor attempt at a previous repair which required us to dismantle much more of the cockpit area than we had planned. However since we had planned to rebuild the cockpit seats anyhow not a big problem just time consuming.

Why anyone would think that they could just lay a new piece of wood over the original water soaked structure and expect it to last is beyond me.

With the new structure in place, we gained about an inch and a quarter in mast height above the water line. The base of the mast does not flex anymore in its position fore and aft as before.

Plans are to still have the cockpit complete by this weekend for the holiday.

I have attached a couple of pictures of the project. More to follow.

By the way, we did this while on the mooring, even had a couple of storms blow through while the mast was lifted. Solid as a rock in reality, but a little nerve wracking to watch the base of the mast kind of oscillate a little during a strong wind gust