Will my 13-ft Boston Whaler keep the motor dry when it swamps (and other Qs)

Question

I've seen numerous web pages that claim that it will keep the power head dry, and some that even say you can leave the drain plug uninstalled (but I'm not sure if the latter applies to with-engine or not).

One note: The transom has a 1/8" stainless plate installed (non-watertightly) on the inner surface, and the bolts attaching the motor pass through the plate. It looks like originally the center foot or so of the transom was made a few inches lower than the rest of it, but that's been built up to flush with a wooden spacer. The main motor support bracket, which I think normally would hook over the transom, is actually about 1.5 inches above the transom spacer. All this raising of the engine may just be a means of accommodating a longer shaft.

So, do you think my '72 13-foot Whaler with a '92 40 hp Force engine can survive a deluge?

Also, can you guess what my mileage will be at economy cruise?

And, is 40 hp overkill for that boat, and can the motor break the transom, with the usual wave slap happening and being cantilevered up so far?

Many thanks for any info you can provide, especially experience-based.

Answer 1

It will float full of water upright and with engine block several inches above the water. I have had mine full of water and was able to pull the plug and drain it with 3 adults on board. These boats are amazing.

Also you can leave the drain plug out when leaving the boat in the water so it will not fill up from rain. Some water will come in from outside but it stops. When you are ready to use the boat again you will have to bail out maybe 2 gallons of water or just leave the plug out while you are running and it will drain out.

My Whaler was a 1966 with a 1986 25hp Evinrude. I could get 10mpg at cruise by myself. The 40 Force will probably get 6-8 mpg.

Answer 2

We were dealers for Boston Whailer in 1972, so I know your boat.  The transum was for a short shaft, an in those days the 40HP was the recommended motor.  I have personally been in the Cheasapeke Bay in a swamped 13 ft whaler with a 40 short shaft. in 5 to 7 ft swells.  The motor would not only start and run,(power head out of water), but it actually caused water to self bail over the transum, and then it drained through the drain hole until almost all of it was out.  I agree the spacer was to use the more common long shaft motor.  Height and bracket isn't as important as the depth of the drive (prop) and angle to the bottom of the boat.   I could run 3 - 4 hours on a 6 gal tank, but I wasn't full throttle much and not pulling skiers.  I hope his info helps. BOL

Answer 3

Boston whaler are foam filed glass lined> Your transon already has issues > raising it 5" weaken the trans> I had a 50hp with a jack plate on mine > It won't sink per say but when full of water it will turn over so the engine will be inverted> Also there is a hook in the last 20" of the bottom> It's called a hull speed> so that much HP will only plow the water with trim it will porpose> I glassed mine flat> And it ran 50 MPH> And could Pull 2 skiers>