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slammin
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I recently sailed my 14ft Kula Cat in 25k+ winds and ripped one of my rails away from its hull. On closer inspection it was due to old rivets failing with age (and my weight 95kg lol). I've since replaced the rail and added more rivets to both sides to ensure it doesn't happen again. From memory I used 6.5 stainless steel rivets from Bunnings and a 4.8mm / 3/16" drill bit to clean and place new holes.

My cat maybe different thou in that the rivets needed to be long enough to pass the steel re-enforcement bar located on the inside of the hull.

HTH, Matt

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I recently sailed my 14ft Kula Cat in 25k+ winds and ripped one of my rails away from its hull. On closer inspection it was due to old rivets failing with age (and my weight 95kg lol). I've since replaced the rail and added more rivets to both sides to ensure it doesn't happen again. From memory I used 6.5 stainless steel rivets from Bunnings and a 4.8mm / 3/16" drill bit to clean and place new holes.

My cat maybe different thou in that the rivets needed to be long enough to pass the steel re-enforcement bar located on the inside of the hull.

HTH, Matt

Yep that's my thought too.

Also I assume your rails are also aluminium if so I hope you used Duralac or similar to stop galvanic corrosion between the ss rivets and aluminium.

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Rivet size for Windy tramp rails is 1/8" or the metric equivalent. You will need to modify your rivet pliers, ( I just use a nut on the rivet tail when it is inserted into the pliers, this will keep the tool face above the track) Use a pin punch to punch the old rivet mandrels out before you try to drill them, a new sharp drill will then drill them cleanly without running off centre. Use 1/8" x 5/8" or 3/4" aluminium rivets only (not s/steel or monel) with duralac on the rivets and sika flex or silastic on the underside of the rails.

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I hadn't considered corrosion to be an issue. Looks like my job is only half finished then' date=' cheers.[/quote']

I think the SS rivets are probably overkill. What was in there originally? If it's aluminium rivets then just use them, save the SS for high strength uses like rigging and make sure you use Duralac or similar barrier goop. Logically there shouldn't be corrosion issues as alloy doesn't rust and SS in essence doesn't rust either. However in a marine environment the use of dissimilar metals can be problematic.

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  • 2 months later...

Hi

my starboard rail has ripped out, and, only 3 intact pop rivets of 26, i took the whole track off for access to get to the bits left in the boat

i drill the aluminium pop rivet heads out from the rail with a 4mm drill and they come out easy

then i tap the bits left in the boat with a centre punch and they fall into the hull, probably for good

can't see any steel kind of reinforcement bar 'though, just looks like the pop rivets go into glass only

what's the best size? Darcy says 1/8" by 5/8 or 3/4 in this thread with duralac goop

but - why not monol?

ta

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Thanking you, Darcy1945. Could you clarify about using the pop rivet gun? I have the scissor / expanda type one made for big s/s applications - so, you put a small nut on the pop rivet shaft such that you can get the head into the rail track?

Some guys swear by using monel only. You can see the point they make..

Cheers

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I've been a bit slack since starting this thread and haven't gotten around to actually starting the job till last Sunday. Too many toys to recondition or maintain aaargh!

Anyway there was some interesting things I found, mainly that the rails had been re-rivetted b4 and the previous person hadn't posted a question on Catsailor. I can tell because 2 of the rivets haven't had the old rivet mandrels punched out 1st..... so the drill has "travelled" into the gelcoat and now the rivet head is a misshapen mess and is STUCK. There is also no sign of Duralac or similar on either rail. The other thing that is more interesting is that 1 rail had the rivets siliconed but the other hadn't. The interesting point is that on the siliconed rail the rivets where in OK'ish shape. Which was in complete contrast to the other side, whose rivets where like powder only a 1/4 of the rivets actually had any substance to them.

I had already done all the rigging rivets and hadn't given a lot of thought to the rails simply because I thought (very wrongly), there's so many rivets they must be OK. Nup, they were all cactus. If you have an older Windy every rivet is suspect. Don't find out in the middle of the bay! Hell, I'm that paranoid now I even did the 2 on the rear crossbeam which don't even seem to do much!

Back on topic. I am thinking that I will just drill a couple of new holes nearby to the stuck rivets on the rail and just clean the top off the stuck ones. Is there any problem or tips with that?

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Thanks Darcy, am going to use the aluminium rivets as you've suggested. The electrolytic paste will certainly use, as have some at hand, and will also sikaflex to rails underside too as you've stated. Got some half tubes left over in the freezer! Lasts a long time there after opening..

Will do both sides of tramp. Cheers good buddy.

Thanks for the tip with the coupla nuts to pull up the pop rivet head to meet the gun through the track too.

Had some monel 3/16" by 1/4 long lying around from a previous job but found the pop rivet head was to big to fit in the track. So got some 5/32" heads by 5/16" long aluminium ones to fit from Bunnings, seven bucks for a 100 pack.

Slammin, good luck with trying to get the old pop rivets out, maybe a centre punch on the mishapen mess will help to drill them out. Probably use a 1/2'' long rivet there afterwards to pull up on the oversize hole left behind. If you a are so inclined you could put new holes in 'though but persist and try to get the old ones out. Certainly interesting info you've shared about the two different rates of corrosion (without the silicone). Hey do you remember those old sikaflex ads where they had two blocks of wood sikaflexed together that you couldn't pull apart?

errata

- center punch the messy pop rivet lightly first so drillbit won't twist off. Use new drill bits, sharp. Drill a small hole about 1/8" first, pretty deep. Then change to bigger drill bit being slightly bigger or about same size of the pop rivet head. Drill in to the rivet until just outside edge of pop rivet is left, it will be quite thin on the edges; then tap off sideways lightly with screw driver and hammer. It'll come off. Then drill out bit left in boat or tap out. If you have biggish holes left in the glass you can patch them with a 2 pak epoxy. Araldite would do, say. Personally wouldn't go putting any extra holes in because might weaken the rail strip..

dos moi pou sto kai ten gen kineso (Gr.), give me where to stand, and I will move the earth [attributed to Archimedes], the lever bloke

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