Transom - dual to single

I am looking to convert a 1962 25 foot Bertram from Twins to Single.

Let's assume that transom is dry and only moisture is directly around the drive 'keyholes'.

Also let's assume that going to a single V8 is not negotiable.

Do you tear out the whole transom core in the drive 'bump out' and replace with a solid 1 pc contigious piece of core material or do you only remove the core materail around the drive 'keyholes' and leave the rest in place?.

I have seen it done both ways... Which is preferable, easier, adaquate, stronger, etc.?

Thanks!

Ian.

 

started a similar project

Hi Ian Dave here My post is just above yours ever herd of anybody trying what Iam dooing ? twin straight drives to a single outdrive. On yours I have read other posts and they sugested redooing the whole transom since you have to holes to fill thanks dave.

 

I decided to tear everything out. Here are some pictures.





I have laminated two sheet of BS1088 Meranti marine plywood together and hope to get them in the boat soon. I decided to sandwich the plys with 1.5 oz mat, 18 oz wovenroving and 1.5 oz mat. I pulled the two sheets together with deck screws on a 6" X 6" pattern. After everything cured, I removed all screws and drilled completely through on the the 6" X 6" pattern. My thought is that this will create some bleeder holes to help make sure I do not have any air between the core and outer skin when I put it in the boat.

Using vinylester on everything.

Ian.

 

Here is the cross section of the core.

Look at all those layers!

1.5" total thickness.






Ian.

 

Nice work

Good choice

 

Core was installed last night from the inside. Thru-bolted with 17 bolts.

Put a nice fillet in this morning and proceeded to put in the inner skin.

I was able to get 3 layers of 1708 wetout and rolled before running out of resin. Each layer inceased in size by about 3 inches.

I am fairly certain that this is thicker than the original, but I had my sights set on 4-5 layers (no reason, just because...)

I won't be able to get back to this for a while, so I am wondering if the 3 layers of 1708 are enough?

Ian.

 

Here are a few more pictures from last weekends work.





Sorry for the glare. 3 layers of 1708.


Ian.

 

Your Gettin After It

Nice work Ian it looks professional and strong enough to hold down a fully blown 454. You must have some experiance with glass. and think out of the box. I have not started my conversion yet but have just installed and proved my power train on an old hull saturday I will remove it and start my conversion soon. rock on . Dave Good choice starting fresh

 

Thanks Dave!

Actually before this, I probably had only wet out a few yards of glass.

Most of my experience is reading on forums such as this.

I have still not decided if the three layers of 1708 are enough. One shop that I spoke with said that 2 layers would be more than enough, one advisor said I should really have 4 on there, others think as much as I can put on but keep the transom under 2 1/4" thick because of the outdrive.

If you have any suggestions, I would be open to hearing them. At this point, I'm leaning towards staying with the three layers because it is thicker than most of what I removed and it was all done in 1 lay-up so no secondary onding between layers.

Ian.

 

Retro Twins to Single Out-drive conversion

Interesting thread...I'm in the throws of doing this with an '80 Formula 302.


I'd really like to go Diesel/WVO with a modified Powerglide into an Arneson 1721/ASD-6s Surface Drive...provided I can overcome the complications involved of controlling the '06 Duramax "Common Rail" diesel fuel system.

However, I may proceed with a Marinized "Pro-Jected" 454/Velvet-Drive into the Arneson, as it's ready-to-go.

I currently stand at installing the revised-spaced Stringers into the Hull and will then proceed with installing the Powertrain...Hopefull to get the boat into the water sometime this Summer : )

Hopefull too that you've been successful in expediting Your conversion, please reply with how well this project has performed, or at least, to what progress you stand-to-date...as this "Thread" is a bit dated : /

Is it working satisfactorily or have you abandoned the project?