Is butyl rubber caulk O.K.

[Diesel Bill]

Hello all, I recently noticed evidence of a water leak from the area around the mast step on deck. I have a couple of tubes of butyl rubber left over from another project. Would this be O.K. to use for sealing on deck around the mast step? If not advised what would be the best recommended sealant for the job?
Thanks for your input.

[steve77]

I'm not familiar with your boat, and am having trouble understanding exactly what you are needing to seal. Is the mast stepped on deck or at the keel? Is this the collar at the deck that needs sealing to the mast?

Thanks and cheers!

Steve

[Diesel Bill]

Originally Posted by steve77

I'm not familiar with your boat, and am having trouble understanding exactly what you are needing to seal. Is the mast stepped on deck or at the keel? Is this the collar at the deck that needs sealing to the mast?

Thanks and cheers!

Steve

The mast looks to be stepped on deck on top of a stainless plate with oversize edges with holes for attaching blocks and shackles, with a compression post under the deck taking the load. Somehow water is getting below in this area of the compression post and the thin wooden vertical panel covering the post and is starting to delaminate and appears to be water damaged. A few months ago this panel was straight and no waviness was apparent. What I want to do is clean around the bottom of the mast and under edges of the stainless plate and pump in some sealant. Smooth or tool it to look presentable and then renew the water damaged panel down below.
What I'm asking is the butyl rubber sealant in a caulking tube O.K. for this application? Anyone got any ideas for a better sealant?
Thanks

[Sailmonkey]

Caulking from the edge may work, but will only be a short term solution. To do this right, you'll need to pull the mast and plate. Clean the sealing surfaces , inspect the deck core for rot, then reseal in the sandwich section and then step the mast.

[Diesel Bill]

Originally Posted by Sailmonkey

Caulking from the edge may work, but will only be a short term solution. To do this right, you'll need to pull the mast and plate. Clean the sealing surfaces , inspect the deck core for rot, then reseal in the sandwich section and then step the mast.

Thanks Sailmonkey, Not the answer I was hoping to hear but it makes the most sense. I planned to do standing and running rigging replacement some time in the future. Now it seems like it might have to happen sooner than I hoped for.
I need to clean the area and get a good close up view of what I'm dealing with.
I'll try to get a few pics when I get to the boat later this week.

[Suijin]

Originally Posted by Diesel Bill

Thanks Sailmonkey, Not the answer I was hoping to hear but it makes the most sense. I planned to do standing and running rigging replacement some time in the future. Now it seems like it might have to happen sooner than I hoped for.
I need to clean the area and get a good close up view of what I'm dealing with.
I'll try to get a few pics when I get to the boat later this week.

It's leaking through the bolts that hold the mast step on the coachroof since sealant underneath has failed. Putting caulk around the edge is not going to do much. The water could well be coming down inside of the mast.

The longer you leave this unremediated the worse it's going to get. Ultimately the core in the deck will fail and the mast will compress it and it will be Very Bad.

If it's ruined interior woodwork there's an excellent chance the deck core has already started to rot. If it were me, I'd take the step off and cut out a section of the deck skin underneath it, at the very least to dry it out. Fix what you find, reglass the top skin back in and make sure you pot the bolt holes with epoxy to protect the core going forward.

[steve77]

I agree with Suijin and Sailmonkey. Sorry, but removing the mast sounds like it needs to be done.

If you do pull the mast, that will give you the opportunity to fix innumerable things while the mast is down. Look at it as an opportunity!

Seriously, best of luck!

Steve

[Tayana42]

Bill, one advantage of a deck stepped mast is the mast doesn't penetrate the deck, just bolts which hold the step plate which are easily sealed. However, the wiring from the mast has to get below and can be a pathway for water to enter. Before removing the mast ( which might be necessary ) check where the wiring enters through the deck. Seal it at the deck and from below. I used butyl tape. I don't have an answer to your question about liquid butyl.

[fatherchronica]

Butyl never really dries all the way. It is able to flex a lot and remain waterproof, but it is really messy to remove later. If you want a short term seal to minimize damage until you do pull the mast I would think a acrylic silicone caulking would be okay. It is not marine grade, but it will be easier to remove when you get to the rigging. If you have access to the bolts attaching the mast step you could pull them a little and put something like Creeping Crack Cure on the bolts. The other posts about actually treating the probably delaminating deck are correct and important. I helped a dock neighbor loosen his rigging and move the mast forward off the mast step so he could do some maintenance that I don't recall now. His mast step had a raised bump that the mast sat around and was so high , an 1 1/2" or so, that we had to completely release the stays aft of the mast and tie them to lines run to winches. It was in a slip and was sort of scary to me at the time. His boat was only about 35', so the mast was a lot smaller than yours. I had a Lancer 36 and as I recall the deck was cored. But it could not have been any more different that the 44' so yours I don't know. Good luck

[Suijin]

Tayana makes an excellent point, which might in fact address the whole issue. If on exploration you find that the water is coming in through the wiring chase, you've probably found your problem. Seal it up and if you don't get more water coming in, issue solved.

It sucks to take apart interior cabinetry/trim, but it's less work than cutting up your deck. Take it apart to really find the source of the leak.

[CarlF]

+1 on the wire passage. But as this is a boat, the water could be coming from somewhere else. Water can travel astounding distances and even apparently uphill on a boat before dripping out. This is especially true for leaks over a berth.

While this leak is likely to be just a nuisance, this may be a good time to carefully check the whole mast support. There is no standard for deck stepped mast engineering. Some builders use plywood bulkheads, others used beams made of fiberglass, metal, or hardwood. Sometimes a combination. You'll rarely find a balsa core under the mast. But plywood is a cheap and too frequently used option.

The forces are complex. The mast is in compression while the shrouds are in tension, pulling the sides of the boat in towards the mast step.

So if you're planning to replace the standing rigging, I'd expand the scope. If the chainplates are 20+ years old they are candidates for replacement. Then carefully inspect the entire structure supporting the mast.

Aren't boats grand?

[Diesel Bill]

Thanks every one for the good advise. When I get to the boat later this week I'll remove the inspection / access cover just above the base of the mast. Hopefully I can get a good look at the bolts and wire run. You guys scared the bejeebers out of me thinking my poor boat needs open heart surgery. I do understand the reasons for pulling the mast but to be honest the purchase of the boat took most of my cash savings. I haven't told my wife/better half yet about the need to spend more on the boat than anticipated. I have been lucky so far as being able to do all repairs myself but to be honest this goes beyond my capabilities. I would need a yard with crane and possibly a rigger to go aloft. I've only been up to the lower spreaders to remove/install radar array and put in new spreader light bulbs. Not crazy about trusting old halyards even if they look good. I'm a good mechanic but not a ship fitter/rigger. I will depend on you folks to point me in the right direction. I'm looking forward to getting back to the boat and getting on with it, what ever it 's going to be. I'll take pics and get my grandson to help me post them.
Thank you all for the encouragement.

[Tayana42]

Bill, you are understandably hesitant about going up the mast and still being unsure about what you are seeing in your rigging. You should be able to get a rigger to survey your rigging for 200-300 USD. Then you will know whether you have any problems. When I had my 25 year old rigging surveyed I only needed to replace one lower turnbuckle on my staysail stay.
Best of luck getting your boat into sailing shape.

[Lancerbye]

Having the same boat, I know exactly what the problem is. The deck stepped mast sits on a plate that has a raised center and a triangular hole with an extension that goes through the deck providing wire access. The water comes through the inside following the wires and ending up following the compression post down. This had happened to my boat and rotted out the bottom of the compression post. Remove the teak veneer that is covering the compression post. Do you have access to the hole that comes through. Mine had an a/c unit in the space above the hanging locker. I removed that when I first got the boat. There is a cut out in the compression post that is accessible through that compartment. Use expanding foam to seal the wire through way, from the bottom making sure it surrounded every wire. No more water leaking.

[zboss]

A lot of deck stepped masts cause problems when the stringer support for the mast support begins to deteriorate. As that happens, the rig goes out of tune and the natural tendency is to tighten it up. This happens again and again until your coach roof curves in.

What I am saying is... don't just look at your mast step, also look at the stringer under the mast support when you have a chance. May be nothing or it may be the root cause.