Remounting Motor Bracket

[24gradyjohn]

I'm refurbishing an Offshore that I purchased new in 88'.
Removed the motor bracket to power coat before repowering with twin 150 etec's. I am considering blocking out areas for access to motor and bracket bolts and plugs, installing drain tubes to plugs then filling with closed cell foam instead of reusing Styrofoam blocks.
Is this advisable or should I reused Styrofoam blocks? I'm new to forum and would appreciate any advise. Thanks.

 

[Halfhitch]

If it were me, I would stay with the blocks. They do the job of displacing water but yet can be removed if you ever need to weld on the bracket or bolt on something in the future.
What's that old saying, "If it ain't broke....."

You can still put evacuation tubes in if you want but for my money I would stay with good deck hatches like Armstrong and a shop vac or hand pump if on the water.

 

[24gradyjohn]

After removing bracket and cleaning I found numerous blisters. Removed gel coat blisters and patched with spectrum fairing compound. Getting ready to gel coat.

 

[Ky Grady]

Put a couple of Pilates balls inside through the inspection hole and inflate after you remount the bracket. Inflated balls displaces room for water and conform pretty good to the inside area and won't absorb water over time like foam can. Previous owner of my 228 did it and it made sense to me if my bracket ever developed a leak, no room for water. You can get them in various sizes.

 

[SkunkBoat]

Paint that blistered area with BottomKote epoxy barrier

 

[DennisG01]

Have you verified the wood in the transom is solid? Now would be a perfect (and relatively easy) time to skin the transom and replace the core if needed.

I'll second the notion of not using gelcoat on that area. Gelcoat's main job is to protect the fiberglass. But gelcoat (especially older formulations) is NOT impervious to water... as you found out since you have blisters. An epoxy barrier coat is FAR superior to gelcoat in this application. Or, even just regular old West Systems (or brand of choice) epoxy. Unless, of course, you're planning on gelcoating the entire transom - then it's easier to just do the whole thing with one product.

 

[SkunkBoat]

Have you verified the wood in the transom is solid? Now would be a perfect (and relatively easy) time to skin the transom and replace the core if needed.

I'll second the notion of not using gelcoat on that area. Gelcoat's main job is to protect the fiberglass. But gelcoat (especially older formulations) is NOT impervious to water... as you found out since you have blisters. An epoxy barrier coat is FAR superior to gelcoat in this application. Or, even just regular old West Systems (or brand of choice) epoxy. Unless, of course, you're planning on gelcoating the entire transom - then it's easier to just do the whole thing with one product.

Obviously it has been holding water.

if you gelcoat it, I would still put a sufficiently thick epoxy coat over the gelcoat* in that area. Not like you are going to see it...

****you can't put gelcoat over epoxy

 

[DennisG01]

****you can't put gelcoat over epoxy

Agree. But there's probably no point in even using gelcoat in that area. BUT, polyester resin DOES accept gelcoat and will work just as good as epoxy... if one was so inclined to make that area look good... where no one will ever see...

 

[24gradyjohn]

The damaged was caused by the tops edge sealant breaking down and the motor bracket holding water.
I had the transom evaluated by the Grady dealer in Hilton Head island and used Thermal camera and moisture meter I own. The transom is solid with the exception of a softball size area where the starboard engine cables and wiring pass thru the transom. I have removed the fiber glass and damaged wood from the inside of the transom and repaired with Fiberlay high strength putty/filler then repaired fiberglass.

Blister repair. I removed the gelcoat and used Fiberlay fairing compound then sprayed new gelcoat. ( also repaired any screw hole from old electronics in area)
I plan on installing new access ports with threaded covers in the top of the motor bracket for easy inspection .
I also plan on reusing the foam blocks.

 

[dbiscayne]

was the foam dry when you took it off? if so then go for it.
me personally i've never liked trapping foam where it can soak up water, there are other ways to keep the water displaced. Ping Pong balls have been used in the past but you'll need a lot of 'em for that bracket.

 

[suzukidave]

I'm refurbishing an Offshore that I purchased new in 88'.
Removed the motor bracket to power coat before repowering with twin 150 etec's. I am considering blocking out areas for access to motor and bracket bolts and plugs, installing drain tubes to plugs then filling with closed cell foam instead of reusing Styrofoam blocks.
Is this advisable or should I reused Styrofoam blocks? I'm new to forum and would appreciate any advise. Thanks.
View attachment 6180View attachment 6181

i'd say a definite no to any kind of permanently installed spray foam. flotation foam does not provide "flotation" unless there is a leak. it just occupies space that displaces water that would otherwise get inside if there is a leak. if you get a leak in a bracket, any type of foam will absorb some water. you will then need to remove and discard that foam to repair the leak and then replace with new foam.

i have heard that filling brackets with either plastic pop bottles or the hardshell plastic balls used in kids' ballroom play areas is a better than foam. they don't get waterlogged and can be removed quickly and easily if you require access.

 

[24gradyjohn]

The foam was dry when I removed the bracket but the bracket was 3/4 full of water when I started renovation and there was approx. 6 weeks between draining and the removal.

 

[Halfhitch]

gradyjohn,

When making your decision about how much work you want to put into controlling the floodable space in your bracket, you should start by looking at your intended use. If it will be a trailer boat or a marina dry storage boat there is really no point in having displacement items inside the compartment. It's a day boat and you will be around it and on it, so if the boat starts getting stern heavy you will notice it and take action. If you will be leaving it in a slip, moored or take extended trips where the boat sits unattended for days or overnight, you will sleep better knowing that, that space cannot flood. If you feel the latter is your expected usage then, if it were my route to plan, I would be thinking about the pros and cons of these thoughts...………………….

1 Fill bracket void with closed cell foam blocks that will pass through the inspection hatch, ping pong balls or similar as has been mentioned.

2 Leave the void empty and install a water alarm sensor with buzzer and light at the helm.

3 Leave the void empty and install a raised manual bilge pump fitting so if the water alarm goes off, a cap can be removed and a manual bilge pump inserted.