sealing the mast

The last couple of times that I tipped my boat it was on windier days and I turtled. I thought my mast was well sealed but I know that I took on some water while inverted. I could hear some water in the mast when it was on the trailer and I raised it up and down.

I used 3m 5200 so seal the mast originally. I cleaned crevices with a solvent and applied the 5200 to the seam around the comptip, all rivet areas, the mast base etc. This all seems to be in good condition but clearly water is getting in. What am I missing? What are the key areas that take on water?

I'm wondering if it is even possible to seal a mast comletely. The rotation limiter connection is certainly an area that can't be sealed completely. especially when you consider that it is well under water when the boat is turtled.

i'm going to try again this weekend to clean things up and reseal the mast. I would appreciate any suggestions, techniques, etc.

thanks!
Todd - trying to keep the pointy end up....

May not be terribly convenient, but I'd wait until the next time to go out and submerse the mast in the water before I sailed, or in a swimming pool. Plan on not blowing over that time out and fix before the next trip. One drawback to this method is a small pin hole can conceivably draw water in to the mast and you may not notice it. I've thought about pressurazation and soaping mine in the driveway, but I haven't come up with the best spot to insert the air. I'd suspect that your drawing water in at the comptip joint. Would be best to remove it and start with clean surfaces and lots of epoxy. While it's off you can check the seal in the top of the AL part of the mast.

Good Luck

_________________
hobiejohn at earthlink dot net
Fleet 297

John,

Thanks for the reply. What is the best way to remove a comptip? Mine isn't loose, as far as I can tell. I'm not saying it doesn't leak. I just suspect that it will not just come out with a simple tug. Is the process of removing, cleaning up, and replacing a comptip documented anywhere? What kind of epoxy would be good to use?

I've tried sinking my mast before to watch for bubles. It wasn't very productive for me. Bubbles come from lines, tracks, etc. for a while and the lake has always been a bit wavy to really see a small stream. And then when I do try to seal it up I'm sealing some water inside it. I think the best approach is as you suggested. Take the comptip off, make sure it is dry in there. If anyone has procedure suggestions, please reply.

Thanks,
Todd
H18 in MN where the lakes are now liquid again...

Todd,

Well, since you've done the dunk test, I'd go for the pressurizing and soap test next. My (unsubstantiated) thoughts were to drill in to the mast at the sail entrance slot of the mast track. You'll be above the bottom seal and a have a nice flat spot that can be tapped and plugged with a screw (1/4-20?) and locktite.

Removing a comp-tip will probably involve some heat to loosen up the existing adhesive material (which could be 5200 type or epoxy resin), two people and alot of tugging and wiggling to get seperated. A couple of bags (of the six) in a West System Epoxy Repair kit will be required to fill the void, going back together, so it will not eventually become loose.

If you take it apart, and the upper foam sealer block seems intact, I'd suspect some fitting. And then you can't be 100% sure unless you pressurize it. Sooooo, it looks like the next step is a soap test.

_________________
hobiejohn at earthlink dot net
Fleet 297

Sounds like a weekend of fun!

Thanks for your input.

Fair winds,
Todd

Oh, sorry Todd. I thought the topic was 'SELLING THE MAST' and I figured you were finally moving up to the 20 from the old Stars and Stripes.
C. Wessels

Not this year Chris. I want to give you one more year of practice before I move up...

I'm going to spend a lot of time on Bald Eagle this year. I'll get to 2 open regattas, Green lake and Shell lake. No Hobie 18s in Div 7 to play with anymore. I put wings on my boat this spring so now I'm a cruiser/racer... I could get interesting on the starting line now that my beam is 4 feet wider.

Maybe in a couple years we can both get tigers.

Sealing the mast is tricky, diagnosing the problem is even harder.

Is the water you hear in the comptip or the mast?

Is the water at the comptip mast joint above or below the plug?

Is the mast head plug epoxy foam or soft foam and sikaflex?

Is the joint plug epoxy foam or soft foam and sikaflex?

Remember, the mast is at two atmospheres at the tip when turtled, this along with a hot mast that has expelled air and now cold temperature that make the mast suck water in addition to the external pressure.

After evacuating the water, the two part epoxy foam is the best "cure". The problem is getting the conditions right to work the foam (temperature and humidity are critical) and then getting the proper amount in before it expands. Think turkey baster. Use lots of tape and newspaper, in an outside area where the mess won't matter, Eye protection is a must as is skin protection. This process will seal the joints and ends, but the rivets, even with caps are still suspect. This is all best done by the dealer.

The 18 mast is prone to take on water at the rotater. Are there rivet sleeves on all rivets? I wouldn't remove a factory installed comptip, it won't be the culprit. If it was a retro install remove it, probably not sealed properly. Lack of rivet sleeves will take on more water than you could imagine. I have also pulled water at the base cap, just removed one on a mast I'm repairing and it had very little sealant. Be careful not to break the tabs for the halyard roller when removing. Takes a pretty good hit to get it loose, especially if corroded.

Would it work to inject spray foam with a 30' long tip?

You do not want a foam filled mast. Best with short sections filled as plugs at each end. Foam is heavy and also absorbs / traps water.

_________________
Matt Miller
Former - Director of Parts and Accessory Sales
Warranty and Technical Support
Hobie Cat USA
(Retired 11/7/2022)

Is there any sort of foam plug in the bottom of the H18 mast?
If so, how far up does it go?
I've turtled my 18 Magnum several times, & am thinking some water must get in from the rotator control.
I was thinking a 1/8" hole, drilled near the bottom would allow any water to exit, & it would be very easy to plug the hole while sailing.
If it makes any difference, this is an all aluminum black anodized mast, NOT a comptip.

As I recall from the last time I took one apart (which was a while ago), the rotator bolt passed through a foam plug.

sm

hard to find a small leak. i think soapy water with the mast on a set of saw horses works best. use a very low pressure, regulated, air supply. i believe the problem is, that when out sailing, especially with the black anodized rig, the mast will heat up somewhat in the sun, pushing air out through a small leak. once it is doused in water, it cools rapidly causing a negative pressure, then being submerged, even a few inches, enhancing that pressure variant, the mast will take on water through that small leak.
i find a similar situation with the "Bearing buddies" on my trailer axle. a couple of shots of grease, pressurizes the hub against the spring, keeping water, at the launch, out.
bubbles in a pool may be so small, with pool water environmentally disturbed, hard to see sometimes. the saw horse thing, you are not letting water in, to let air out, to find the leak.