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 Post subject: sealing the mast
PostPosted: Tue Apr 18, 2006 11:16 am 
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Joined: Tue Jul 22, 2003 8:59 am
Posts: 20
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....


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 Post subject:
PostPosted: Fri Apr 21, 2006 6:30 am 
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Joined: Tue Jul 05, 2005 8:45 am
Posts: 759
Location: Clinton Lake Lawrence, KS
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

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hobiejohn at earthlink dot net
Fleet 297


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 Post subject:
PostPosted: Fri Apr 21, 2006 7:04 am 
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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...


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 Post subject:
PostPosted: Fri Apr 21, 2006 7:44 am 
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Posts: 759
Location: Clinton Lake Lawrence, KS
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.

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Fleet 297


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 Post subject:
PostPosted: Fri Apr 21, 2006 8:53 am 
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Sounds like a weekend of fun!

Thanks for your input.

Fair winds,
Todd


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 Post subject:
PostPosted: Fri Apr 21, 2006 12:59 pm 
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Joined: Thu Jun 05, 2003 9:57 am
Posts: 1588
Location: Clear Lake Iowa
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 :P


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 Post subject:
PostPosted: Fri Apr 21, 2006 1:38 pm 
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Joined: Tue Jul 22, 2003 8:59 am
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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.


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 Post subject:
PostPosted: Wed Jun 14, 2006 10:07 pm 
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Joined: Sat Jul 02, 2005 9:47 pm
Posts: 577
Location: San Diego
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.


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 Post subject:
PostPosted: Thu Jun 15, 2006 8:13 am 
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Joined: Wed May 17, 2006 7:49 am
Posts: 1070
Location: North Carolina
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.


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