Toughening up the motor mount

[Ted]

Well, tonight the admiral and I set out for a short, almost sunset cruise. We had a great sail last night and were in a hurry to get out on the water before the sun dropped too low.

So I ran my motor over the bouy tie off like an idiot. First time for me. It gave the motor quite a  tug. I was looking down at the transom and noticed that the metal plate was not sitting flush on the fiberglass. I am not sure, since the boat has only been with me about a month and I don't remember inspecting it, but I probably bent the mount a little.

It got me thinking about the backing of the motor mount and so I looked underneath and was a bit surprised to just see a washer and a bolt. So it's got me thinking. I am going to pull off the mount and straighten her out anyway, so perhaps I should strengthen this a bit.  I found the pic below on another site - my mount has four holes, not eight.

Anybody do this or something similar/better??  I was thinking about trying to find a stainless steel plate with four holes drilled into it.

[skip1930]

The mount on the CP-19 is bolted on with just 4~1/4 inch hex head bolts [not the softer carrage bolts] and finished on the inside with a flat washer, a lock washer and a nyloc nut, all of this glued on with some 3-M 5200 slow set just around the bolt holes and going through a ply wood hard point glassed onto the transom.

The motor mount rating found for this mount in the West marine Catolog says good for 20 hp. I running five. A 4 to 1 safety factor. The transom is plenty strong but another backing piece of ply wood, or aluminum, or UHMW glued on with some epoxy will make you feel better. And make your boat heavier, right where more weight is not wanted.

skip.

[Billy]

The fact that it bent the metal plate and didn't crack the fiber glass makes me think the current setup is more than strong enough.

I'll take a look at mine tomorrow and maybe take a picture.

[Salty19]

I moved this from the DIY section.   the DIY area should be used for posting how you did something as opposed to asking how.

[Ted]

Sorry...

[MacGyver]

Ted,

One thing we do is not use wood, just as a idea, you can make Fiberglass supports like that using Biaxial or regular glass and epoxy.
Once those are put in, no need to worry about them rotting out 

But, what you have done is something I plan to do, even though the transom is strong as hell, you want to ensure that it will put up with loads that arent planned necessarily........

I plan to do my swim ladder on my 19. There is some gelcoat stress cracks around the bolt areas that led me to know that some stress has been a problem.
The PO was a much bigger guy than I, so I am sure I am good, but hey, a little reinforcement never hurts. 

That wood you have is a good addition, but think about replacing it later when you have spare time and arent enjoying sweet sailing weather 

Mac

[Ted]

Mac,

I haven't done that wood arrangement - that's a sample I pulled from another site. I was thinking stainless steel plate. When I have the motor on and it is in the up position, I see a little wobble in the plane of the fiberglass. That's probably not how it was new. It holds fine, but I do worry.

[Tom]

Last fall I purchased a CP 23 that, along with many other boats,  had been driven hard aground in a Hurricane.  I don't know if the mount was used to pull the boat off the shore or if the motor caught on something and was nearly torn from the boat, but the mount was very  badly bent and twisted.  However, you'll be happy to know, still firmly bolted to the stern.  When I went to replace it with a new mount I ran into the problem with the locking arm hitting the rub rail. so I took a piece of 2x10 lumber, cut it to be slightly larger than the motor mount base and put it between the mount and the stern, got longer ss bolts and real big washers and bolted the new mount on thru the new 2x10 "pad".  Looks good and now the locking arm clears the rub rail.               

[skip1930]

" When I went to replace it with a new mount I ran into the problem with the locking arm hitting the rub rail. "

I see this is the first posting. Welcome aboard. This hitting the rub rail is a common problem.

I ground off enough aluminum so the 'pull-up' handle would clear the rub rail.
Then made an extra plate to bolt onto the mount. This extra plate hung down lower than the factory plate.
And from that new plate was added four 2 inch by 2 inch rubber blocks.

Thus the O/B is 2 inches further into the water and two inches further away from the transom.

When I get my boat back out of winter storage four new and longer pivoting/horizontal arms will be saw cut and bolted back in...pulling the O/B even further back away from the transom.

skip.

[skip1930]

Question? What say the group.

Should the rudder casting be sitting on top of the transom casting or be under the transom casting?
By going lower, that puts the rudder further into the water and below the protection of the keel.
It also lowers the tiller almost to the top of the cockpit.
The have a wood screw under the tiller that can adjust the angle of the tiller.

I do have a pinned rudder shank so this rudder no longer pivots up when snagged on seaweed or rocks.
I replaced this snowblower shear bolt [shown in the picture] with a pin and a lanyard.
That keeper holds the spring pin in place. The spring pin has a second lanyard on it.  
Pull the two lanyards and the rudder is free to swing.

Thanx. skip.