posted 11-06-2013 10:50 AM ET (US)        

I would like to “raise” the transom on my boat to accommodate 25” shaft twin engines. I already have a pair on there and the extra shaft length is affecting the performance of the boat, and any future engines I might buy are likely to be 25” shaft engines. Additionally, new engines are likely going to be somewhat heavier than the current engines – so having a higher transom height will help the boat manage that weight by keeping water out of the splashwell.

The biggest question is how do I go about raising the height of this transom while retaining transom strength and rigidity needed for twin V6 outboards? Can it be done without replacing the whole transom, or will I have to laminate in a whole new transom? My current thinking is to remove the whole outer laminate and core and only part of the core near the top and re-laminate in a new core section near the top and use the new outer core section that would extend down to the keel for the rigidity/strength.

posted 11-06-2013 04:28 PM ET (US)         

It was an alteration done in the glass shop after the complete hull was first manufactured as a standard hull.
Back then, additional cost was $1000., but I have no idea how they actually did the modification. You might consider contacting them for advice and how-to information. Maybe they will even do it for you?

If it were my boat, I would simply install an Armstrong bracket with the top surface at the new 25" height. This would be 5" higher than the transom notch, and with small side platforms, would span across it, keeping water out and effectively giving you the 5" higher transom. Then a nice teak slat platform could be built at the height of the bracket surface and covering the original splashwell.

You could walk right out on the platform & bracket if you wanted to, and overall boat performance would be nicely improved over transom mounted engines. If you took a huge wave into the boat, the water can still run out the back, although the pair of 3" transom drains would still be needed.

posted 11-06-2013 06:14 PM ET (US)            

I like the option of a bigger transom bracket...and have discussed that before as well. I just want it to look really good when it's done --and since I'm going to be redoing a lot of the gelcoat back there anyway, wanted to explore options.

posted 11-07-2013 09:12 AM ET (US)            

--they used an engine bracket with a buoyancy box--the Whaler Drive; they did not use long set back brackets without buoyancy boxes on their classic hulls;

--when Boston Whaler added the Whaler Drive they built up the transom height, and they used three long support rods from the Whaler Drive transom running upward to the new, higher transom, to carry the load.

Further, your 1983 hull is now 30-years old. The age of the hull would also make me consider carefully adding to it the load of a long engine setback bracket. Finally, there is the cost of such a bracket: they are expensive.

posted 11-07-2013 09:17 AM ET (US)            

I saw an account of a person that did exactly what you are thinking about doing, for the same reason. I believe it was documented on Whaler Central. Unfortunately, I can't seem to find the information to direct you to it.

I think I understand your doodling, and as I remember, the procedure they used to raise the transom was similar.

I like the idea of raising the transom height better than using a bracket, though it is probably the more costly of the solutions. Heck, I would like to have a 30" transom on my 22. The further out of the water the better when backing down into the weather, while trying to keep your bait on the bottom.

posted 11-10-2013 01:47 PM ET (US)            

I finally found the information I mentioned earlier this week concerning raising the transom on the 25 hull. See below:

http://www.whalercentral.com/userphotogallery_3.php?album_id=369

posted 11-10-2013 01:50 PM ET (US)            

I guess my link only gets you close to the info. After you get to that page, go to page 2 of 3. The album is noted as "Outrage 25 Restoration", at the top of the page.

posted 11-12-2013 05:39 PM ET (US)            

Be careful of the CMC fixed 5" lift extension.

My 22 came to me with the 25" engines lifted by a pair and they did not provide enough lift.

I ended up changing to a pair of Lift plates from Bob's Machine shop, though if I had it to do all over again I would use 4" aluminum square tubing to fabricate my own lifts.

You could then fabricate a custom splashwell dam extension, or just use something similar to what the walleye fishermen use for back trolling.

posted 11-12-2013 07:40 PM ET (US)            

The only real roadblock is getting that cuddy shell off the hull and then safely flipping that big bertha over.

posted 11-12-2013 11:17 PM ET (US)            

Do you think the boat needs flipped to do the transom modification? I think the boat in the project needed some work that required flipping it over, but didn't think the transom modification was the reason for flipping it.

posted 11-20-2013 03:33 PM ET (US)            

Re: changing gear case: I don't think counter rotating is available for 20" shaft motors. Plus, since the existing motors have 25 inch shafts, the point is moot. I'm not going to blow $25K plus on new power and then another $5k to try to change out one of the gear cases...my money would be better spent to get a bracket for $2K installed and run 25" shaft engines with full warranties from the factory.

Twin hydraulic jack plates will cost about the same as a nice bracket with swim platform. Again, it's a give and take where and how to spend money.