Redoing a 79 mako, epoxy or ester

[fallguy]

Can you explain the transom pictures a bit better?

Why is the transom thicker on the area behind the fish boxes?

can you take a top down picture for me?

I am a bit worried we are making a mistake here building back to the fish boxes. The engine loads need to transfer into the hull.

The fish boxes can act as gussets which is a good thing, but not if the transom is not contiguous across the back.

Wish a few others would post comments here.

Martin--any opinion about this? @bajansailor

 

[fallguy]

See drawing. The blue arrows are not good.

 

[Hojo]

I'll do my best. This is a 2 piece boat. From what I can see and limited research I've done into the history with these boats it appears that the thicker top was part of the molded top which included the deck. This was placed onto the hull section and secured together. It appears that the top half carried the load the motor exerted. I will not just be using fish boxes as only area. I will be bringing glass from outside back up onto gunnel caps on both sides thereby locking the hydrotek sides to that and also wrapping that same glass around to inside area above fish boxes. That same cloth will be tabbed onto the fish boxes. Then after I put new deck down that will be glassed in the same overlapping sequence you described up and over new hydrotek essentially tying it back in as close to original design. I am raising the deck 1-1.5". This will bring the new deck up to the thicker 1/2 area. Then that will be the place I glass deck to transom and up n over...not sure that answers your question...

 

[Hojo]

This is top of gunnel area I am talking about. I will grind gelcoat off the inside area above fish boxes and about a foot in just on the sides, not all around like you show in diagram..so area circled will be down to bare fiberglass.

 

[Hojo]

Also won't be one big piece of glass, but several smaller over lapping ones that I can work with...

 

[Hojo]

And if I don't feel it's good at that point I will grind sides of hull on outside and glass from transom on to that as well...but I don't think that will be needed...

 

[fallguy]

So, what goes in here?

one piece of hydrotek?

 

[fallguy]

I was worried you were only putting the plywood core on the inside. The picture helps tons.

 

[Hojo]

I am putting 2 18mm bonded together. That will leave about 1/4 inch...the outside skin is just a little over 1/8"...leaving room for a couple layers of glass on that...most likely will epoxy that skin to hydrotek and cover that with a layer or 2 then fair it out as smooth as I can....

 

[Hojo]

No just adding glass inside for strength and to even it up...

 

[fallguy]

I am putting 2 18mm bonded together. That will leave about 1/4 inch...the outside skin is just a little over 1/8"...leaving room for a couple layers of glass on that...most likely will epoxy that skin to hydrotek and cover that with a layer or 2 then fair it out as smooth as I can....

You will be fine. I was worried you were only putting partial sheets inside. The picture tells the story. Carry on!

 

[Hojo]

Ok. Thanks for the assurance I'm doing the right thing....will update with pictures as it progresses along...

 

[Hojo]

First layer of plywood rough cut in....2nd layer will have splice on opposite side....

 

[fallguy]

When you do the bonds, I recommend 1/8" vee trowel to existing substrate.

Each surface of the plywood panels must be prewetted about an hour before bonding because plywood will drysuck the resin from the bondline. Use 1/16" vee trowel onboth sides of the follow on layers. Or 1/8" one one side, but both is best. Use pins and bolts to apply light clamping pressure 2-4 psi throughout. The best way is 3/8-16 bolts well waxed. Remove them after about 12 hours for best results.

The thickened resin must not sag out of the vee shape or it is too wet.

 

[Hojo]

I was gonna coat all the plywood both sides and edges after sanding a radius. Left them dry completely clean any blush off and rough up the flat surfaces....then bond 1st layer to substrate as you mentioned...do 1 at a time...let that dry completely, clean surfaces again and do 2nd layer as above....I think that would be best way so I don't get rushed and f... something up....and yes will use bolts heavy with wax, maybe throw a couple of 2x4's also...will make sure it is tight all around...thank you for advice and suggestions....