question about motor mount/rudder backing

[whitecap]

 Hello all, i'm new here & have a question.   i'm fixing up a 1982 cp16 & wondered if some folks could please poke their heads inside the cockpit lazarette storage area & tell me if the motor mount & rudder gudgeon are backed by plywood or metal plates as originally installed by Compac.  thanks alot!

[mrb]

Ahoy whitecap and welcome aboard

Not sure they are factory but my 16 has plywood backing for outboard mount.  From memory I think the rudder backing was metal.  My boat is at dock and I havent been down there in a while so this is all from memory. 

Hope this helps.

Wishing my lake had a lot of white caps then I would have the wind to go with them.   Hot and still all month aaaaaarrrrrrrgggg.

[nies]

Whitecap, my 1978 only had washers for backing, I added ss plates to every thing, I like over kill..............Phil

[Salty19]

There is no specific backing in terms of plates or wood to backup the nuts.  There are just normal sized washers used.

BUT...the better portion of the transom itself, in all mounting areas (including swim ladder) is cased in 3/4" plywood.  Therefore the transom is wood cored, adding add'l strength in this area.

When I swapped out the motor mount on my old 82 for new (old one was worn out!) and added a swim ladder, I used large stainless "fender" washers, appx 3" diameter to backup the new motor mount bolts and ladder bolts.  Wood or aluminum plate could be used as well, and many have used these materials with success.   Use something that will not corrode. And most importantly, don't tighten the bolts down super hard like you would on a lugnut.  30ftlbs should be plenty after first tightening all bolts to 20ft lbs.   Make the seal with bedding compound and even bolt tightening.

Some may tell you to use 3M 5200 on these areas to seal them but that will make them a bear to remove at a future date.  Use bedding compound instead.  I used 5200 and looking back that was perhaps not the best way to go. Whoever redoes the work in 20 years is going to curse like a true sailor getting them off.

I left the rudder mount alone. No cracks or leaking and decided to not alter anything here.

By the way this job was tough because of tight compartment clearance (I hope you're skinny) and siezed bolts (hope your strong).  I had to use an air grinder and chisel to remove one of the motor mount bolts (nut and bolt were completely seized and an air impact wrench would not fit inside the area to get them off).  The other 3 came out with a lot of cursing and swearing using a standard socket wrench and air wrench once they were loose.

So I suggest spraying first with a penetrating lube and be prepared to use alternative measures should a bolt or two be tough to remove on your 28 year old boat.  Hopefully you'll get lucky and they will come off without a lot of fuss.

[jkat]

Whitecap,

     Funny you ask about this.  I finished up working on this same situation today.  I've got a '77 cp16 and the motor mount and gudgeon bolts are originally backed with washers that are all of 3/4" wide.  I've been trailering mine for the last five years with my Yamaha 4hp on the motor mount and have always been a little nervous about the pressure on the transom.   I finally got around to buying some flat and wide aluminum stock to use as extra backing.  I've trailered my boat about 10,000 miles with the 37 lb motor on the mount and there was not a single sign of any stress on the bolts and washers when I checked it out today.  I still installed the backing plates for extra insurance and for the sake of using what I'd bought. 
     These boats are built to last.  If I were to do it again, I would have saved myself the trouble of cutting and drilling the stock and used fender washers that were 1 1/2" or more in diameter.
    Happy sailing

Jkat