Water in mast

I bought an early 80s model 16 earlier this year and have taken it out a handful of times. Have not flipped the boat, yet I realized the mast seems to have a good amount of water in it. I'm assuming this is from rain / condensation.

Boat has an all aluminum mast and from what I can find online there are essentially three compartments inside. Two small ones on the top and bottom and a larger main compartment in the middle. The water sounds like it is in the middle section.

What is the best way to drill / drain the mast? Also, what is the best way to repair afterwards?

My understanding is there is a mast plug just above the mast base, and another one just under the main halyard sheave.

Rattlenhum said:


I'd probably drill out the rivets for the base & halyard sheave, and re-seal the plugs. To drain it, you could always drill out one of the cleat or cheek block rivets. If they need to be replaced this would be a great time to do it. I got all my parts, including rivets, from Murrays.
https://www.murrays.com/category/boat-hobie-16/

Those rivets are a bear to pull by hand, but a Harbor Freight pneumatic gun makes it easy. I had to use the hand puller on the mast cleats due to clearance. I could have turned the nosepiece down on the lathe but elected to get some exercise.
https://www.harborfreight.com/3-16-inch-air-hydraulic-riveter-93458.html

_________________
Bryan
Poplar Grove, IL
1977 Hobie 16 (died a spectacular death https://youtu.be/Y7O22bp2MVA)
1978 Hobie 16

Hey there, sounds like a leak to me and I would strongly recommend fixing that ASAP because just a small amount of water in the top would make righting difficult. If you think about the physics involved when turtled, you would have a lot of pressure on the top seal and the mast tang rivets. That is probably where it enters. I recently replaced all of my mast rivets and plugs to be sure mine will not leak. If you have any loose rivets that is a problem. To remove I buy those brass colored high speed metal drill bits. 3/16 inch only. Drill at low speed with moderate pressure and once the outer ring pops just tap the rest into the mast with a nail. They will fall out if you pull out the bottom plug. If you replace the mast tang rivets, line them all up at the same time or the holes my not line up after the first rivet is installed and like the other post mentioned, you have to have a very heavy duty tool. I got one from Amazon that works fine. The mast also has special cup shaped parts that you have to use with them to prevent leaks. I would just do the entire mast and be done with it. It is definitely a leak, not anything else.

Oh, I also put a dab of silicone on each hole before riveting. If you have any corrosion, clean that off and put a little spray paint over any bare metal. You can use black high temp rustoleum paint on black masts or clear outdoor type lacquer if aluminum colored just to keep corrosion at bay.

Just don’t do what I did. I had all the rivets inserted into the tang so it looked like a porcupine and the mast rolled over and one rivet stabbed my finger tip. I can tell you that really hurt so be careful.

Randy

Murray's has a .pdf that lists all the parts they have for sale. One cool thing is they specify all the rivets and rivet casings (special cup shaped parts) that you need for each item riveted on, as well as the quantity required. You can download it from the Murray's link I posted above, or directly here:
http://www.murrays.com/wp-content/uploads/2018/09/Hobie-14-16-parts.pdf

_________________
Bryan
Poplar Grove, IL
1977 Hobie 16 (died a spectacular death https://youtu.be/Y7O22bp2MVA)
1978 Hobie 16

Some additional info on fixing leaks in the following Hotline issue.

http://www.w1dm.com/Projects/HOTLINE/15-2HOTLINE.pdf

For draining the mast, if your mast has a sail feeder in the luff track opening, you can remove the screws for the feeder and drain the mast that way. Otherwise, you can drill a small hole in the mast (~3/16”) near the bottom to drain, then plug the hole with a self tapping screw or use a tap to thread the hole and install a #10 machine screw.

Unless you’re sure that the foam plugs are leaking, I would probably avoid removing the mast end caps and messing with the plugs.

sm

Oh right Bryan, those little cup shaped things are call casings. I could not remember what they are called, but the parts diagram does show where all they are required. One thing about ordering the rivets - Many of the rivets look similar. Murray’s seals each type in plastic but they are not labeled so you have to be careful to figure out which ones are which. Some rivets like the ones in the mast cleat are recessed and it is impossible to seat the rivet unless you put a spacer on the rivet. Murray’s sells a little part just to do that. I improvised by putting a bunch of drilled off rivet heads on the one to be popped.

It is really not that bad fixing this as long as you get a decent rivet tool. Without one you will do a lot of screaming trying to pop them.

Randy