306 Bimini Repower

[5tool]

Hey guys, new guy here thinking about purchasing a '99 hull bimini 306 that has been repowered with twin 350 yamm v8's via a armstrong bracket.

I've read the threads regarding the repowering of this hull and most recommend against those large motors but, nobody mentioned using a bracket. What do you guys think? The install was done by a reputable shop and talking with them, they have assured me the hull plus bracket can more than handle the motors. almost 300 hours on the repower and i don't see any cracks or signs of stress on the transom.

What do you guys think? Any input is appreciated and I hope to be part of the GW frat soon!...

Thanks!

5TOOL

 

[bc282]

i'd be concerned and need to investigate to be sure the boat will be satisfying. first i've heard of a 30' bimini with F350's.
initially i feel the boat is actually over powered with twin v8 F350's and doubt that in '99 it would be spec'd to handle the power.
Power is one issue, the weight is another significant issue as is safety and legality (if greatly overpowered as per mfr spec's, insurance and liability could be serious).

Does the boat "squat" when at rest and where do the scuppers sit while at rest?

Boats generally have a power sweet spot for hull to engine combination. It is bad to be underpowered and not great to be over powered especially if the engines' weight factors into the performance. Over powered boats may go faster, but the "sweet spot" for cruising may be far from your ideal boating use and burn much more fuel than the "correct" power to hull combination.

i would think the new v6 F300's would be fantastic for the bimini, i'm sure there are yami perf. reports with this engine config to compare to the typical F250s config which is fine too.

It has the engines on a brackets? hmmm. brackets usually place additional stress on transoms as it increases the leverage against the transom. I should think a bracket was done since the large engines likely would not fit on the factory transom. Transom beefed up by a yard to handle F350's?

please take a good sea trial and make your decision.

i'd also think that with the F350's would make this "older" boat a rather expensive repowered buy. I'd imagine it cost about $45k for the repower.

 

[5tool]

Thanks for the reply. I know the hull shouldn't have been repowered with the v8's but the bracket is the key. I'm hearing with the bracket can make this type of repower doable.

I will definitely have a qualified person take a look and consult me.

Thanks again!

 

[NOTHING ELSE MATTERS]

That boat was rated for 250 HP, you might have a problem insuring her. I had a 2006 306 and that boat never needed more than 500 ponies.
I also think that your scappers are under water, not a good thing.

 

[ElyseM]

obviously what's done is done.

did the shop also reinforce the stringer system? that's a lot of weight and torque on the transom and it's leveraged as a result of the bracket. i would keep a close eye on all the interior joints to make sure nothing evolves.

good luck with it. ron

 

[5tool]

Thanks guys, seems the consensus is the v8's were a bad idea.

 

[ElyseM]

just keep a close eye on the joints and avoid "hole shots", long period high rpm running, and wave jumping. you'll probably wind up with many years of service. good luck, ron

 

[Grog]

So someone put a bracket on the end of the eurotransom? Run away! Just because the bracket is rated to 700HP, the hull isn't. Twin 300 HPDI's may have been an option but going 100HP over is nuts. Just try to get insurance and if you do get in an accident you'll be hung. The balance is probably off too, the extra 400+ pounds 20 inches further back isn't going to help the ride.

 

[ElyseM]

HOLD EVERYTHING!

i mis-read your post. thought you did the repower and were looking for post process support.

i am wholly in grog's boat :mrgreen:

i actually talked with GW about what they felt about repowering older hulls with the new v-8's. they said that any hull still under warranty would be voided immediately. they also stressed that no reputable yamaha shop would perform such a repower.

i was trying to help you anyway i could think of when i thought you already did the work. as grog said, run away and go find a good boat to buy.

good luck, ron

 

[BobP]

An armstrong bracket was installed on the 30 ft Grady's integrated transom ? That's a lot of weight cantileved off the original transom with any motors on it.