Sealing the inside of a keel stepped mast?

[cornr 0]

I have a keel stepped mast that has what looks like a foam seal at the level of the lowest halyard exit. Unfortunately, it is leaking and every time it rains I have water in the bilge. I am wondering if anyone has a good suggestion on how I might repair this. I am thinking of healing the boat and pouring in some sort of sealant to try to plug the gaps? I could probably spare about 1cm above the level of the current seal and still use the halyard exit without problems. Thanks.....

[harrytom 641]

You are talking litres rather more like a cup or 2?? I have seen foam poured in to stop leaks but water ,a mix of fresh/salt sitting the mast helping the corrosion process,be better to let water out. 

[Psyche 624]

 Theres a sika product thats used for in teak decks that may work 298? not 100% sure  but call the tech support and ask since it's about 15 years ago that I did it.  Pour it in, the only trick is to make sure you have a suitable drain hole for the water

[wheels 543]

Spartite is what you are looking for. A chandlery may sell it or ask a boat rigging business.

[Neil C 1]

Duram 195  has worked for me . Get it from Bunnings / Placemakers

[Winter 42]

11 hours ago, wheels said:

Spartite is what you are looking for. A chandlery may sell it or ask a boat rigging business.

Isn't that for going around the outside of the mast? between the mast and the deck?

[wheels 543]

Spartite is a multi use pourable Urathane based Adhesive Sealant.
It is available in a Kit which comes with a boot, to be used as you say, for between Mast and Deck and is designed to "chock" the mast in position. It can also be used internally as a seal.
It is not the only Urathane bases Adhesive sealant available. Electrical Trade suppliers have a similar product for pouring aound cables to seal them. But I cannot say if it will be perfect for such a job, where as Spartite is purpose designed for the job.
The main issue of course will be adhearing to the aluminium when it is gong to be a corroded surface and near impossible to clean. I suggest perhaps an acid aluminium cleaner brushed in around the area and then a darn good rinse out and good dry before pouring in the sealant.
 

[Sail Rock 28]

I had this problem a few years ago. Took the mast out while doing other refurbishment at a boat builder. Found aluminium conduit that conveys masthead lighting cables inside the mast had severely corroded allowing water to track past the foam plug. Pulled that out and removed the remains of foam plug as best I could. Replaced conduit, fitted some closed cell stop ends inside mast: one at bottom halyard (topping lift) outlet, the second about 300mm further down. Then squirted Gorilla foam in between them. After foam had set, removed the top stop end by hacking it to pieces with various sharp implements and pulling the bits out through the topping lift exit hole. Finally, trimmed the top surface of the Gorilla foam plug with a hacksaw blade to roughly level with bottom of exit hole so water could drain. Hasn’t leaked since.

Note also have Spartite between mast and deck collar, topped with a bead of sealant, which works well.

Also note that years ago I tried a flowable Sika silicon product which was very expensive. Poured it in through the topping lift hole down to a stop end inside the mast. But it ended up finding it’s way through small gaps between stop end and mast, flowing all the way down to the mast step!!!

[cornr 0]

Great, thank you all for the suggestions. I will have a look, I suspect the conduit may be part of the issue as it is loose at the lower end. 

[Chewing Gum 17]

I used that pourable sika product, can't remember the name and it worked for a while then started leaking so I slightly thickened some epoxy and poured on top - that worked. I think the sika didn't get right around the back of the cable tube.