foam inside masts?

[Joe Nelson CS#35]

Since I am making my masts so that they dont come apart (3 part), would it be smart to pour boyancy foam into them to keep any water out?

Is the added weight a problem? Would this reduce mast bend? Will this make the masts stronger?

I think it would take just over a couple cubic feet of material. Foam weighs about 2# per cubic foot. Doesn't seem like weight would be an issue for the benefits it would provide.

[Noklin]

I have the same questions about filling my CS20 mast with foam. This should increase safety by decreasing the chance of turning turtle during a capsize.

[JeffM]

My masts are take-apart (for garage storage). All sections are 8' (plans call for 6' top section), and my top section has wood plugs epoxied at both ends. If I did the math right (couldn't find a calculator), each of my top sections has an interior volume of about 1/3 ft3 and so a buoyancy of 20# or so. Foam may only weigh 2#, but that weight is in the worst possible place. I could only make sense of installing foam if it filled at least the top two sections: in my recent capsize test, the top two mast sections submerged, and my rig was almost adequate to keep the boat from turtling. For my part, in heavy weather I'll haul up a float on the mizzen staysl halyard.

[Scott Dunsworth]

The last issue of Good Old Boat had a article on boat satiability. Part of the article was given to welding the mast tube watertight or filling with foam. They gave figures on the amount of leverage that a 40 foot mast would have. I know we are using around 20 foot masts, but still it sounded like something I will want to do.

Scott

[Designer]

I think that it is important to keep the water out of the mast. I caulked every part of my masts as I rigged them including every rivet as I put on the sail tracks. When I water tested the masts, water leaked out of the rivets leaking between the mandrel and the rivets. I am hoping that I can fix the problem by filling a sryinge with caulk and injecting it into the mandril hole.

I don't have any problem with pouring foam into the mast. I tried to foam a mast many years ago and it is not easy. The suppliers say to mix the foam thoroughly for 20 seconds and pour it by 30 seconds. I found that by the time I was satisfied that it was properly mixed and started to pour, it was expanding long before the foam reached the other end of the mast. What I ended up with was a big mess and a foam plug in one end of the mast. All of this was done while up on the roof so that I could get a reasonable slope on the mast. Having the mast vertical would help and try to pour the foam without touching the sides of the mast, which slows the resin's movement, allowing it to start expanding and plug the mast. Maybe foaming the masts in sections would be easier.

[Joe Nelson CS#35]

Even with Graham's warning about the difficulty, I ordered some foam. I will try it in sections and use my second story deck to pour when I get to the second section and a ladder on the deck for the third. I'll let you all know how it goes.

[double 7]

why not inserting swimming noddle inside mast. this is wath i have done, you can reduce the diameter of the noddle on the bench saw or with sharp knife. and compress it to the required diameter and secure with ligth tape and insert it ? double 7 fern

[Designer]

I like the noodle idea.