AI Crack in stern adjacent to rudder mount

I recently purchase a 2016 adventure island second hand and found that it has a leak. It is coming from a crack on the port side of the stern, starting right under where the rudder attaches. The crack start on the stern (under the rudder mount), then runs 1.5 inches up the port side. Serial number is US-HCCJ1108B616





Should I be concerned about the amount of stress in this area when there is force on the rudder, and do I need to do anything more than just repair/fill the crack (reinforce it in some way)? Any help would be appreciated.

Thanks,

Brett

Hi Brett,
For some reason I can’t see your pictures but based on your explanation, that area is pretty tough. Hard to imagine what caused it to crack. First I’d try to stop the crack from growing by drilling a small hole on both ends, then using a plastic weld kit and simply melt/seal the crack (inside too if you have access). Then go enjoy the boat…inspect the repair….if it returns then try to figure out what is causing the stress in that location. Repair again and re-inspect. Good luck

Have you removed the rudder and then the rudder mount? The rudder is just the pin, the mount is 2-3 Phillips Screws.

If the crack is all the way to the brass molded inserts, that could be a major problem. Also try shining a bright light from inside towards the stern and look from the outside. You should be able to see if the plastic thickness is even, or thinner in parts (I've seen much variance in older hulls).

You probably should be working with a Hobie dealer to file a claim if any of the above shows anything more.

_________________

Hobie Island Sailing since 2006

Thanks for the suggestions. I took the rudder off and now see that it does go through to the brass molded insert. There is a Hobie dealer an hour from me that is a Certified Warranty Service Center so I will give them a call tomorrow and go from there.



https://photos.app.goo.gl/2VCEyBD7VoH4559W6

Thanks again for the help,

Brett

To get the image to show up, I opened the page using your URL. I right-clicked the image and then opened it in a new tab. Then I right-clicked that one for a URL that I copied... then it worked.

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

That's a bad crack. You said it was leaking so it should be fixed.

I would first bring it to a Hobie dealer and file a claim. Even though it's a 2016, Hobie often stands behind their products even after warranty, so you never know. The hull should not have cracked like that under normal use.

If you have no luck with that, you have two choices.

1). Replace the hull. That would be very expensive and would require refitting the entire boat.
2). Repair the crack. This is not easy to do for a DIYer. Properly fixing a crack such as that in polyethylene is not easy because it's a very difficult material to properly repair. Few things stick to polyethylene so glues, caulks, and other fillers don't work well. It should be plastic welded. You could try to do it yourself but you might make it worse or not be able to repair it properly. If it were mine, I would bring it to an expert. There are people who know the proper methods for plastic welding. Since a lot of boats use plastics these days, you can often find them at boat body shops. Or sometimes they'll just be listed under plastic welding.

If you decide to try to fix it yourself, then at least go onto YouTube and watch videos on plastic welding and plastic boat repair. This will demonstrate how it's done.