Engine mount box repair/replacement

[craze1cars]

Hello....I'm new to this, so looking for tips for a first timer. Got a 1992 Rinker 181 18 ft open bow with a 3.0 Mercruiser I/O for nearly nothing due to significantly rotted engine mounts and box caused by years of improper storage. Motor is hoisted out and I've been cutting and hacking and removing all the soaked and rotton wood and surrounding fiberglass in the engine compartment. The hull & transom appear to be solid.<br /><br />My completely uneducated plan was to rebuild a similar to original engine box out of dried, pre-shrunk pressure treated pine "2-by" boards (assuming there'd be more "bite" in a thick board than in the original plywood for the engine mount lag bolts to hold better), assemble the box with stainless screws, and then encase all in fiberglass with a simple fiberglass kit from an automotive repair shop. After curing, remount and align the engine & drive-line.<br /><br />After reviewing a lot of these posts, I've been hearing a lot of talk about epoxy. I never considered anything different from a basic fiberglass resin/cloth kit for this repair, as I assumed that's what the boat was originally made of. <br /><br />Can someone please explain a sound process to me? Where/when should the epoxy be used, what brand, where can I buy it? Where/when should I fiberglass? Is my treated 2 by deck board plan good or bad? Originality and appearance in the engine bay is not a concern for me at all...just looking for a solid place to properly mount my engine to so it doesn't rock and shift. I don't want to break the bank, and I want this thing back on the water by spring. Maybe 5 years of recreational use will hopefully follow, and then trade it in for nearly nothing as I fully recognize that this boat will have no significant resale value no matter what I do to it.<br /><br />Thanks in advance for any tips you can give a newbie on this project.

 

[Laddies]

Re: Engine mount box repair/replacement

pressure treated lumber of any size adds alot of extra weight and nothing bonds well to it check around for a West System Epozy Manuel it will be a great help to you

 

[oneoldude]

Re: Engine mount box repair/replacement

What follows will probably result in flames. But here it goes anyway.<br /><br />FWIW, my local polyester and epoxy resin supplier tells me that polyester (common boat fiberglass resin) will stick to wood perfectly well when properly used.<br /><br />This is what I was told:<br /><br />First, the wood must be dry as possible. Most pressure treated wood is sold wet and must be dried before application of polyester. If you laminate with poly while the wood is wet there will be poor bonding. If dry the bonding will be maximized.<br /><br />Second, there are two general types of polyester resin (and gelcoat for that matter). There is stuff with and stuff without wax in it. Most of what is sold has wax in it. The wax is used to insure complete cure and a slick non-tacky surface. The stuff with wax does not bond well to wood or to its self. Therefore, you should get both types. Apply the non-wax stuff for bonding to wood and for multiple fiberglass laminations and when done put on one last thin coat of the waxy stuff. That way you get the best bond and still get a complete tack free finish. <br /><br />I am told the same holds true for gelcoat. By that I mean that when you are done with the non-wax poly build up then put on a few coats of the non-wax gelcoat until the color is what you want and then finish with a coat of the wax gelcoat. You will get maximum bonding and still get a shiny tack free finish.<br /><br />Also, you might check out these links:<br /><br /> http://www.glen-l.com/wood-plywood/boatbuilding-plywood.html <br /><br /> http://www.glen-l.com/wood-plywood/wp-index.html#index

 

[Peter J Fraser]

Re: Engine mount box repair/replacement

oneoldude,<br />I went to my local boat builder when I was starting into my project. He is a major user of WEST System Products so that is what I ended up using.<br />It has worked well on all the surfaces I have encountered so far.<br />Glass, Old timber, New Timber, even me, the lot.<br /><br />Peter

 

[flashback]

Re: Engine mount box repair/replacement

A couple of years ago I re-did the engine beds in my 21 ft chris... I did away with the wood completely.. I made the beds by covering a 4x4 with wax paper and then laying up 3 sides of it up with glass to a thickness of about 3/8 inch...after it kicked off, I removed the 4x4 and cut the beds to fit then glassed them into the boat.. drilled mounting holes and bolted the mounts on with machine bolts and nuts.. not lags......worked out great and no wood to rot...

 

[craze1cars]

Re: Engine mount box repair/replacement

I myself have given some serious consideration to a carriage bolt/nut type of mount system myself instead of the lags. Might still do something like that. Overall, it sounds like just about anything goes, huh? Glad to hear some innovative ideas here and there, as I am not very inclined to duplicate the original construction of this boat considering it failed dramatically in it's first 12 years of life. Anywho...I've been learning quite a bit by looking at everyone's project photos, etc. This is a great site to take in. Please share any thoughts/photos/stories to help keep me motivated.

 

[Chris1956]

Re: Engine mount box repair/replacement

I like your plan to use dry PT 2-by wood for the engine mounts. Poly resin will stick nicely to it and I would use several layers of glass to assure it is bonded securely to the hull. <br /><br />It sounded like you will also need to create a removable motor box or cover. For this I would use dry 1/2" pressure treated plywood. Cut it to size and use temporary fasteners in the inside to hold it while you lay a couple of layers of poly resin and glass on the outside. You only need to cover the joints in the box with glass, but cover all the plywood's surface with resin. Especially the endgrain. Now remove the temp. fasteners and glass the inside of the joints and resin the entire inside surface. This box will be stong, weatherproof and cheap. It may not be so light or have a great appearance, however. It may be covered in rug or vinyl, for appearance improvement. Use SS Staples or adhesive.