how will this work on this boat?

Aloha everyone.

I have a hull that is built by Force Marine out of Hilo, Hawaii. The model is a commercial Force 30 hard top. The boat is thirty feet long and is a heavily built all glass construction. It is set up for sterndrive. Originally i wanted to put some yanmars with the bravo x drive but i couldnt afford it. I will be using this boat for diving fishing and will be carrying alot of additional weight on board. My trips are about a hundred miles round trip and i plan on cruising at around 20 knots. Since i cant afford yanmars i have my eyes set on a pair of Merc 4.3 MPI fuel injected with bravo 3. Any ideas of how this boat will perform with this setup. Longevity, maintenance, fuel efficiency, etc.

thanks in advance

attached are the pics of the boat

Re: how will this work on this boat?

That's a chevy 4.3 V6. I don't think you'll have any issues with the motors themselves. From what I've read, the bravos seem to have a good reputation.

Re: how will this work on this boat?

Welcome to iboats.

The question is how much use will it get? The Yanmar is about 50% better in fuel efficiency and over the longer run......it may pay off. A pair of gas 4.3's will require a fair size fuel tank ........

Re: how will this work on this boat?

How much is the boat going to weigh? You stated that you anticipate carrying a lot of additional weight as well. I think anticipated weight of boat and gear will be a significant factor in determining the power requirements. I have seen twin 4.3's on some 28-30 ft. Express Cruisers. I'd look at what the production boats in the same size and weight are being equipped with from the factory as standard and optional equipment.

If this is truly a heavy boat for it's size and you also intend on carrying heavy loads as well, I have to wonder whether twin 4.3's will be sufficient.

Re: how will this work on this boat?

Why not add a seadrive to the back and a pair of 275HP O/B's?

Re: how will this work on this boat?

shrew said:

How much is the boat going to weigh? You stated that you anticipate carrying a lot of additional weight as well. I think anticipated weight of boat and gear will be a significant factor in determining the power requirements. I have seen twin 4.3's on some 28-30 ft. Express Cruisers. I'd look at what the production boats in the same size and weight are being equipped with from the factory as standard and optional equipment.

If this is truly a heavy boat for it's size and you also intend on carrying heavy loads as well, I have to wonder whether twin 4.3's will be sufficient.

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Check on the Cobalt 293. They did offer twin 4.3's and from what i understand, it is still a 50 mph boat. I believe the dry weight is around 9000 lbs.

Re: how will this work on this boat?

dsiekman said:

Check on the Cobalt 293. They did offer twin 4.3's and from what i understand, it is still a 50 mph boat. I believe the dry weight is around 9000 lbs.

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Please note:

shrew said:

How much is the boat going to weigh? You stated that you anticipate carrying a lot of additional weight as well. I think anticipated weight of boat and gear will be a significant factor in determining the power requirements. I have seen twin 4.3's on some 28-30 ft. Express Cruisers. I'd look at what the production boats in the same size and weight are being equipped with from the factory as standard and optional equipment.

If this is truly a heavy boat for it's size and you also intend on carrying heavy loads as well, I have to wonder whether twin 4.3's will be sufficient.

Click to expand...

Re: how will this work on this boat?

thanks for the replies. I was periodically checking in on the site to see if anyone answered but none for the first couple days so i figured no one would(nobody likes me)

My typical workload will be 2500 to 3000 lbs in addition to the hull, engine/engines and passengers.

I checked with my mechanic buddy yesterday and he has a yanmar 370 that he could set up with Vdrive but we would have to make some mods on the engine box and the deck to allow for 9 feet needed for the setup. I am contemplating all options and that doesnt sound so bad. Plenty of horsepower/torque and maintenance issues long term seem to be minimized. He seems to think that sterndrive just will not last nearly as long as Vdrive for semi commercial use and long range trips. He also seems to think that i am going to get my arse ate up on fuel with twin 4.3's

So, i am getting a quote from my buddy on what it will cost for the engine,vdrive,shaft,components and then i have to figure out what the builder will charge for the deck modification. If they are high, i might take on the challenge myself to keep cost down. Right now the deck is raw and the box is as well.

Any comments?

i will keep you guys in the loop, and thanks again for the help

Re: how will this work on this boat?

That was pretty much my point. Put 10 x 300lb guys on that Cobalt 293 with twin 4.3's and see if the boat can get up on plane, never mind running at 50MPH. All things are relative. If the boat is heavy (relative to other boats of the same LOA/Beam) as well, it will exacerbate the issue.

Re: how will this work on this boat?

Nobody answered you because your in Hawaii and were all jealous!