Transom Mounted Outboard

[Steve]

Hi Guys,
on my 563, the outboard motor transom bracket is wobbling around real bad, the mechanism of the actual bracket is some of the fault but also at fault is the wooden block that spaces it out from the transom, it is weathered dry and warped. Again I have found problems regarding bolt heads and nuts pulling their way though timber. I better get this fixed before I'm hanging onto the fuel line fighting the outboard like a 25kg tuna. Its also a good opportunity to repair some pretty ugly plugged up holes from previous outboard mountings.

One thing I'm wondering is , do you guys have a glassed in gusset behind the outboard transom, there has been an attempt to fit one here and I'm going to have to remove it to redo it but I'm wondering if it is necessary to replace it.
Your thoughts please
Steve

[Yara50]

Steve,From your pic it looks like the transom was cracked at one time. Instead of the gusset I would be inclined to reinforce the inside of the transom with some glassed in marine ply. Use expoxy resin for improved bond. When you do the internal reinforcement, taper the edges gently to avoid a stress concentration. I replaced the o/b bracket with an expensive Italian alloy and spring counterweighted version, which is good except that the main pivot bolts are carbon steel and starting to corrode.

[Steve]

I started looking for a new transom mount for my outboard, but I figured the one I have works well in principle, its made of stainless but it just has too much play in the hinges letting it rock around. The pins in the hinges are welded in( and some of the welds have cracked) and there is no way of closing up the tolerances.

Cracked welds on the hinge pins and elongated holes in the mount plates

I decided I would replace the pin hinges with bolts but I will need to make spacer tubes to stop the hinge crushing as I tighten the bolts and also some bushes to give a larger bearing area on the mounting plates. I disassembled the mount and bored all the hinge points out to 12mm. I then made spacers and bushes out of 12mm od stainless shaft with a 5/16" bore and welded them in place.

Spacers and bushes ready to weld in

It all went back together with four 5/16'" bolts and tightened up perfectly

Bolted back together and slack hinges eliminated

Now back to the glass work on the Boat, still a little unsure what to do but will have a better picture once I get the old gusset removed.

[Steve]

Got a start on my transom repair. I basically just ripped out the old gusset by hand as it had never bonded to the glass of the hull, there was even a bit of water between the hull and the gusset lay-up. With that out the way a close inspection reviled no cracks in the transom wall and no de lamination of the glass. The only things to repair are the old elongated holes from previous outboard mountings along with the gelcoat cracks that radiate out from them. It is so tempting to just fix the holes then build an outboard well at the base of the transom at the rear of the cockpit( like some Tophat 25's) ,,, But I would rather go sailing than work on the boat, besides, I've all ready missed too many appointments with the Freo doctor

There is a total of 12 holes in this side of the transom, I will patch all of them then re-drill the four that I need , eight of the holes opened out into four big holes.

Steve

[no way]

While you have your head in the hole doing that dastardly job I suggest you seal the gap at the top of the cockpit seat to the transom(top left of your pic).
The bit of gusset already in place in my boat was frp encased tin plate. If you seal this and the same on the stb side then with the correct ventilation you can safely put the fuel tank in there without fumes going into the bilge

[Steve]

While you have your head in the hole doing that dastardly job I suggest you seal the gap at the top of the cockpit seat to the transom(top left of your pic).

Good point,
I guess I will be back in there tomorrow with the grinder , but I will check first with regards to access to transom mounted hardware, may need a removable access section, shouldn't be too difficult, thanks for the heads up.
Steve

[Ozzie]

Steve, I should know this or may have known and don't remember ,but what is the construction of the transom? Is it laminated ply with glass, solid glass, T1000 liquid metal?

[Steve]

Ozzie,
It's fiberglass and polyester resin right through, aprox 5/32"-1/4" thick, I'm just glad its not ferro cement.
Steve

[Steve]

Finally back to work on the transom, I decided to go with the Idea of another gusset that runs from the top of the rear transom/combing mould to the bottom of the locker and along the rear wall of the transom.
I also added a couple of layers of some woven/chop mat glass that I had lying around the workshop to give the wall of the transom more thickness.

It all stuck back together nicely and has braced the motor mounting area real good

[Steve]

I shaped up a new mount block for the outboard bracket out of three pieces of ply I laminated and re-drilled the holes in the transom.

I made some backing plates from Ply and machined up 4 large washers 1/8" thick from 316 and assembled it all back together with ny-lock nuts and sealant.

With the outboard mounted up ,the assembly is now 100% better,,,, I had been procrastinating over re-spraying the whole transom with flow coat, so,,,,,,,, being kind of chuffed about the outboard mount, I removed the rudder mounts to start the job only to find nuts sunk into ply because of no backing plates , I Started thinking where else, so I ripped the crappy mounted stowage shelves off the inside of the hull , then tore off the carpet to expose the chain plate fastenings for the masts shrouds, It was all buried in flow-coat so I removed all the sails and cushions from inside the boat Again,,, and hit the suspect area with the grinder, guess what????? Two 1/4 inch nuts nearly pulled 3/4 of the way through the 1/2" ply pad they are mounted to

It's starting to get kind of depressing owning this boat!

Steve