What would happen if i welded the dolphin striker/mast mount to the front crossbeam on a Hobie 18??? Your thoughts and opinions

the welding might cause some localised hardening and brittleness of the alloy in a highly stressed area

the hobie 18 has a reputation for being overbuilt so maybe it would be ok

probably a good idea to search hobie forums to see if any/many have had beam deformation/failure in that area

i think the 80's nacras did have problems in that area and that nacra made alloy sleeves to go inside the beams and spread the loads better, so it would probably be a bad idea on an old nacra that was loaded to the limit and used in high winds



edited by: erice, May 27, 2009 - 04:55 PM

hmmm that is somthing to consider... the reason that i need to weld it onto the crossbar is b/c the rivet holes have become to big and will not hold the dolphin striker/mast mount to the crossbeam anymore.

Welding sounds dicey unless you are an expert (if so you probably wouldn't be asking )

Could you drill new holes in the mast step casting and beam and re-rivet? Fill in the old holes with J-B Weld.

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Damon Linkous
1992 Hobie 18
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There are some pictures of a damaged mast step on a Hobie 16 being replaced here. The H18 is very similar.
Replace Hobie 16 Mast Base

PLEASE be sure and take pictures of both your damage and your repair whatever you decide to do and add them to the Beachcats Technical section. Your experience will help the next H18 owner.

Thanks,

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Damon Linkous
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They do make larger rivets, the original ones are probably 3/16 would it help if you went to 1/4 or larger. You will just need a good rivet gun if you go beyond 1/4. It seems like it would be a safer way than welding.

I had the same problem a few years ago... I just used a larger sheet-metal screw, It worked fine !! then sold the boat.... I know the guy and he has had no problem with it.
So screw yer boat & sell it !!!

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Well sounds like ill give you guys some back story.... We first had this problem on the crossbeam when we discovered a crack in the metal.... we got that piece cut out and had it a nice new piece of aluminum welded on. At the place that did the welding they drilled new holes in the crossbeam that were to large.... We did finde some Sheet metal screws and used those for a while no problem.... but soon the threads sheered off.... so now we are eliminating the problem by welding the sucker on the crossbeam... ill take some pictures of it and post it up here.... My biggest concern was what will the effect be with the tension bars that support the dolphin striker..

I think that welding the base to the beam will only give you a brief fix. The beams are thin and the welding will weaken the metal. The constant flex will crack it right at the welds. You may want to try the new style base with 4 rivets. That may last a little while, but you wouldn't have to weld.

I would look for a replacement beam. If you can't find one with the newer style base, you may be able to machine it so that you can get more rivets through the base. If you have to have it shipped, then it may get a little pricey, but the beam itself wouldn't be much more than a weld job. You can recycle your old beam, too!

I agree with dan

If the metal is TIG welded... it will not produce a brittle heat affected zone. TIG welding stress relieves itself as it cools. It is the only easily accessible method to do so. So long as you match the correct filler material. In cases where the two sections are made of the same material, filler material is not needed if TIG is used, simply put to the sections in contact and blend them.

well i just happen to know a few people that can work wonders with a welder so i already got it done for free... maybe i should now try to drill some holes and also rivit it to the beam??

Could you not have filled the holes with the welder and then redrilled them? I am fixing to do this with my mast because of some corrosion at the rotation bar.


Dave