I was sailing in the Hong Kong Hobie Asian Classic at the weekend, great conditions (a steady force 4) and fleet of around 35 hobie 16's and 15 or so other catamarans, and was having a real blast when the dreaded bang of something breaking happened. Well it turns out that one of the rudder mountings (called a Gudgeon in the catalogue) that hold the rudder pin came clean off the hull which forced an early retirement. Damn!

Anyway, when I got back to the beach I find that the four screws that hold the mounting in place are all still in the hull and the tops had all sheared off around 2-3 mm inside the holes.

Anyone got any idea how I can repair this and be sailing in time for next weekend's regatta?

Cheers
Rob.

not sure how to help you ,but am very interested in this asian classic.Do they have charter boats?thinking of coming over one year
Mike
Can

Yeah, we had quite a few international entries this year, including Peter Bates (17th in the last worlds I believe) who won the event. We had six brand new 16's for charter this year and hopefully have something similar for next year. When we know the timing for next year's event, I'll get a posting on the forum. You can check out our fleet at www.hobie.com.hk

get a set of bolt extractors.

You're gonna need a tiny one for a bolt that size though.

Don't get cheap bolt extractors! I have found that dispite my somewhat OK mechanical skills, I have found that bolt extracting is a somewhat difficult task to do well. In other words to drill a hole on the old bolt shaft without taking the threads can be difficult. I am lucky, I get the (aircraft) mechanics at work to do bolt extractions. If you do a bolt extraction, be very careful doing the punch for the drill to start in and use a new, sharp drill bit so the drill hole is a good quality straight hole. Put bolt anti seize oil in the hole to free up the old bolt. Probably stand the hull up so the oil can penetrate.
Cheap extractors will break, compounding the problem and the frustration.
Basically the idea is to use the largest extractor you can withut having to drill such a large hole that you ruin the bolt hole threads.

Sounds like you are lucky that the bolts broke rather than some other part, like the hull!. Probably was designed that way.

You've run into one of the gnarlier problems in Hobiedom. The gudgeon bolts thread into an aluminum plate laminated into the transom of the boat. The SS/aluminum interaction as well as the fragile mechanical properties of aluminum make repairs difficult. Also, unless you have ports installed in the back of the boat, you are only able to work from one side.

Repair suggestions in ascending severity:
1. Remove fiberglass from the transom enough to expose the now-headless bolts and remove them with pliers or some sort of threaded coupling. Reglass and rebolt.
2. Bolt extractors. Agree that this would be very tricky and the chances of going 4 for 4 pretty slim. Could end up with an even bigger mess.
3. Drill out/redrill for the next larger size bolt and retap the aluminum plate.
3A. Sounds like you have the 2 piece gudgeons. Get the newer one piece gudgeons. These require 2 new (tapped) holes anyway but I believe they use 2 existing holes so partial step 1/2 may be required.

Good luck!

Thanks for all the advice it sounds like a much bigger job than I was hoping for, as it always is. I just had thought, but not sure if it would work. If the screws go into an aluminium plate in the hull, then is it possible just to keep screwing the screws into the hull so that they will eventually fall through to the other side and can then be taken out through the drain holes at the bottom? I suppose it's a long shot, but thought I'd ask.

I'm going from memory here but I believe what you suggest is possible. The aluminum plate is drilled and tapped after the hull is constructed so the holes should go all the way through. If you want to go this route, I recommend installing a port so you can see the inside of the hull.

Also, you can try e-mailing Matt Miller at Hobie Cat USA. I'm sure he has seen this problem many times. He visits this BB but an e-mail may be quicker.

Hmmm I don't know if that is true but if it is then get some loosenall type of bolt unfreezing liquid raise up the hull so the fluid will seep in around the bolt and try to turn it. Problem is how to turn it.

Ther only way I can think would be to use screw extractors but they work the wrong direction, so you would drill a hole and put a small screw driver that is larger than the hole and bang it in with the hammer and try it.

Just be careful you don't ruin everything in the process.

It looks like cmerrill is right but proceed carefully whatever you do.