I've just bought a secondhand Al Khubar, getting it ready to try on the lake tomorrow, but it failed the bathtub test while sorting out the ballast.
There's about half a cupful of water in the hull after sitting in the bath for a couple of hours.
The water appears to be getting up the propshaft tubes. I thought I would just take the shafts out and re-grease them, but I can't.
The boat is fitted with two Torpedo 500 motors with 2.5:1 gearboxes. The motor mounts are screwed to wooden blocks, and I can't access 3 of the screws because the deck gets in the way.
It has fixed Kort nozzles, with the rudders about 5mm behind the boss at the centre of the prop, so very little clearance. The props aren't fitted with locknuts, and I can't get the shaft out of the prop - I guess they are glued on. I can't remove the rudders to slide the shaft out along with the prop, because the bottom of the rudder shaft fits into a fixed skeg. It looks like everything is stuck together with epoxy and car body filler.
So, I can't remove the motor or coupling, or the prop, or the rudder without some drastic surgery.
To top it all, there's quite a bit of axial play in both propshaft bearings. The bearings are black plastic rather than bronze/brass, and the threaded part of the shaft goes inside the bearings - looks like the shaft is a bit too short, or the tube a bit too long. I'm guessing that this has worn the bearings out, and no amount of greasing will stop the water getting in. The bearings should run on the unthreaded part of the shaft, but they don't. No thrust washers fitted either - the prop is touching the bearing at one end, the coupling locknut is touching at the other end.
I think I'm going to have to remove everything, fit new shafts, etc - unless anyone has a better idea?
Does anyone have the build instructions for the Model Slipway Al Khubar, so I can see how the Korts, skegs and rudders go together? It'll make life easier dismantling everything if I can see where the various parts are glued together, it's a bit of a mess with glue, paint and filler covering everything.
Also, is it possible to remove the gearbox from a Torpedo 500, so that I can unscrew the motor from the mounting bracket? As I said, I just can't get a screwdriver onto the woodscrews that fix the bracket onto the wooden blocks that are fixed to the hull.
Looks like whoever built this boat didn't give any thought to taking the running gear out for maintenance.....