December Power & Motoryacht: Bertram 25 Reborn

[Tommy]

Current issue of P&MY has a nice article with lots of pics where a couple of Aussies took a B-25 Flybridge I/O and turned it into a Bahia Mar style boat with an integral bracket carrying twin 300 HP Suzuki's. Top end is 45 kts; cruises at 32 kts. The integral bracket carries the hull surface aft 30-36 inches, which provides both additional flotation to carry the weight of the OBs without upsetting the attitude of the boat, and also provides additional running surface. Both the running attitude and sitting attitude look perfect to me.

[CamB25]

The integral bracket carries the hull surface aft 30-36 inches,

That's the secret sauce!

[Rawleigh]

I just saw a 25 flybridge on a trailer with two outboards on an Armstrong bracket. I could not get pictures of it unfortunately and could not tell what the outboards were. The 300 Suzuki's are nice outboards. i have a friend who put two on an Armstrong bracket on a 30 foot Scarab Sport. They are so quiet that when he runs up to my dock all i can hear is the sound of the water off the hull. And he is getting almost 2 MPG at 45 knots.

[ktm_2000]

I am curious............

Cam's boat, as reported in posts here before the T-Top was 48mph and after the T-Top 45mph or 39kts and that is with a single 300hp motor, another person here with a 300 zuki and a sport convertible had similar speeds to Cam before the T-Top.

What does putting 2 x300hp get you? 5kts? seems like a lot of additional resources working against diminishing returns.

I would suggest if you wanted twins and faster than @40kts, 2x200hp would be a more appropriate power option, less cost and less weight on the transom.

To me going after top end speed is a little crazy, I ran my boat mostly at 75% rated engine RPM 3600/4800rpm at @22-23kts and the boat was quite nice. When given a bit more throttle, it seemed to break free and run a bit better at >24kts.

I am hoping that the single 300 will let me cruise easily at 24-26kts at 75% rated engine rpm and anything beyond that will be a treat to be used sparingly on a FAC day.

[Tommy]

KTM, I agree with your logic….

[beachbum]

https://m.youtube.com/watch?v=BurX5_WEyNg

Yeah I agree, the 2 Tasmanian guys who stuck a pair of Yamaha 200s on a 25 FB saw 40 knots. 50% more hp for 5 knots...

Though can't argue with the work, looks fantastic.

[ktm_2000]

I watched the video that Beachbum posted about the boat and those guys put quite a bit of effort into making a really nice boat. Stylistically it doesn't match my tastes but it they appear to have done an amazing job building and finishing it. My boat definitely won't come out anywhere near as nice as that rig.

I think that they put quite a bit of stuff in that boat and the weight probably accounts for the perceived lack of speed. Also when at rest the rear of the chines are a couple inches in the water so the overall displacement of that boat has to be on the high end of the scale for B25s and the engine power is probably needed.

In the video he says he had 9 people on board and hit 46kts so if you take a bunch of the human cargo out, the boat is probably a 50kt boat.