I/O (Sterndrive) Conversion to Outboards

[tpenfield]

1 transom cavity filled with 1" of fiberglass . . . 1 more to go.



22 total layers of 1708,1808, CSM combination . . . 1 gallon of resin.

 

[flashback]

Getting pretty heavy eh..

 

[tpenfield]

For those contemplating making a thick plate of fiberglass as I am doing . . . Don't

My method has been to lay up CSM & 1708/1808 in alternating layers. I was originally thinking about 22 +/- layers. When I get to 3/4" of build-up, I place some plastic sheeting over the fiberglass in the cavity and use the 1" Coosa piece that I cut out as a 'tamp' and apply some weight to flatten the fiberglass out, so that it is even. Here is a picture of the cavity filled to 3/4" , 'flattened', and cured. . . . It has about 1/4" more to go to be level with the surrounding Coosa.

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Since my shop is fairly cold for fiberglassing (60˚F), it takes a while for the resin to 'kick' . . . but once it does . . . holy cow . . . quite a bit of exotherm !
The piece gets up to about 120-130˚F.

After curing, I add more layers of fiberglass to get up to the 1" thick. What I am finding is that I need about 25-26 layers of glass to get to the 1" . . . probably because of the CSM layer is not as thick as the 1708 and 1808 layers.

I hope to be done today with the inserts and then moving on to the next thing . . . which may be glassing in of the planing surface.

 

[Scott Danforth]

Hey Ted, Mercury is showing the new 808 hp outboard at Miami. you could get by with one motor.

 

[alldodge]

Hey Ted, Mercury is showing the new 808 hp outboard at Miami. you could get by with one motor.

and loose the joy-stick, ohhhh no

 

[Pmt133]

Hey Ted, Mercury is showing the new 808 hp outboard at Miami. you could get by with one motor.

Yeah... but I'd still want twins.

 

[flashback]

1600+ hp, that would be sweet!

 

[Scott Danforth]

1600+ hp, that would be sweet!

Ted may be currently contemplating another layer or so of fiberglass......

 

[tpenfield]

Hey Ted, Mercury is showing the new 808 hp outboard at Miami. you could get by with one motor.

perfect

 

[tpenfield]

Getting pretty heavy eh..

Yes . . . But all for a good cause

My latest estimates, based on the recent changes are

Bracket ~ 500 lbs.

Hull Modifications/bracing ~ 200 lbs

Very little weight reduction overall . . . about 200 lbs.

 

[Scott Danforth]

Ted, how many cases of beer will fit in the bilge where the two 6.2's used to sit?

Did you figure in the weight of "provisionings" in your calculation?

 

[tpenfield]

I got the transom inserts done . . .

Here is a picture of the process . . . rolling out each layer to ensure that there are no air pockets. I add the resin (~ 5 oz. ) for each layer and then lay the cloth on top of it so the resin soaks upward into the cloth (or mat), forcing the air out.

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It is a tedious process, but it works. I calculated the glass-to-resin ratio using a volume calculation. Each cavity is 275 cubic inches and I used a gallon of resin (230 cu. in) on each. So, the glass content is about 16% by volume. It seems pretty low, even though I painstakingly rolled the glass to force the resin up from the layers below.

Here is the transom with both inserts glassed.

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[alldodge]

Looks good, did ya ever think about aluminum plate or honeycomb aluminum plate?

 

[tpenfield]

Looks good, did ya ever think about aluminum plate or honeycomb aluminum plate?

No, because of temperature coefficients of aluminum vs fiberglass, foam, etc.

 

[tphoyt]

I learned about that hard way as a kid. I glassed over an aluminum plate and it delaminated in the first winter and I was living in Fl at the time. To much movement between the 2 different materials from the temp change.

 

[tpenfield]

The Admiral has been busy doing make-overs on the bathrooms. Fortunately there is one bathroom recently re-done so we have a place to

Her commitment to me, so as not to distract from my boat bracket building, is to do most of the work herself. Still, I find myself being a home improvement supervisor fair amount of the time.

Meanwhile, I have been getting ready to start writing big checks . . . on engines and controls. I've got about 8 quotes and may get a few more in the days to come. Between the sticker shock of some of the re-power quotes and my diversion in having the Naval Architect review my design, the budget has looked like run-away spending.

Looking at the re-power quotes, I can certainly tell 'who is hungry' and who is not. There is about a 20-25% swing in the numbers. I should have my course plotted sometime next week. I'll need some help from the weather forecasters, to get the work within the boat done.

One thing the Naval Architect suggested is that . . . not only use adhesive (5200) as well as the plethora of bolts to fasten the bracket, but also scarf joint the bracket to the hull around the perimeter with 3 layers of glass. I like the idea as it will remedy chances of the bracket leaking if the adhesive seal fails. It does change the manner in which I finish the bracket . . . Originally, I was going to gelcoat it before installation. With a scarf joint, it would make more sense to gelcoat the bracket after it was installed. That sequence of tasks may prove to be beneficial.

 

[tphoyt]

The number almost always go south. It’s part of the game. But it will be sweet in the end.
Are you going for 2025 left overs or fresh 26 models?

 

[tpenfield]

The number almost always go south. It’s part of the game. But it will be sweet in the end.
Are you going for 2025 left overs or fresh 26 models?

In the 300+ hp range, I don't think there are leftovers. The re-power craze has gobbled them up like bacon & fries.

 

[Pmt133]

Hey Ted, if it sways you any... I just got back from the boatshow and they had a new Suzuki 300 that was leaking oil from the gear case on display.