I need some help with hull specs

300 hp ? Your boat is not suited to such engines, is your measurement of "baw"= beam at waterline=70" ? I am not surprised the builders don't want to talk about it ! Realistically, your boat is designed for a lot less hp and engine weight than that, it does not have the bulk and werewithal to cope with it. Even less so as a round-bilger. It is a little bit hard to tell from your pictures, but if the bow area of your boat is similar to the boats illustrated on the Lake Winnipeg site, I don't fancy it for a jet-drive boat either. Others may have different opinions, they'll be along to give their impressions before too long.

 

The hp and torque are a rough estimate with these motors it is simple to get them into 300 hp range

 

Bear in mind you need a "clean" bottom ahead of the jet intake, there seems to be some kind of moulded-in skeg/keel along the bottom, which might mean butchery. Still want to do it ?

 

No those boats are the new 25' models. Different bow, I don't know if the rest of the hull is similar though. Yes beam is 77" beam at waterline 70"

 

He'll yeah I wanna do it I've cut lots of meat in my time . And about 300 hp papa learned me goooood.

 

As a rule of thumb, I would venture that any boat that can plane happily with a 60hp evinrude will be completely overwhelmed by anything remotely close to 300 hp. You are putting yourself in harm's way, imo.

 

I read about the sixtys they are around 230lbs dry. So basically 500 lbs hanging off the transom. A 5.9 weighs 900 lbs but is moved inboard probably 2' I think the difference in motor weight will be so minute because of positioning the hull will barely notice any difference.

 

Yeah I hear yah but it's the only suitable inboard engine I have.

 

So you want to take a stab at the hull weight I think it's around 2000-2500lbs. Maybe less though due to it being open.

 

Plus the added weight near the stern might give the hull more of a bow proud stance under power. Now if it's to high a trim able nozzle will help or even planing tabs. The weight could counteract the high c/l thrust of the jet

 

I would not be in a hurry to ditch the 3cyl OMC power, great engines with very good fuel economy, for a highly speculative venture that could end in tears.

 

There is no denying that everyone of your answers have been sound advice but there is just something that is telling me to do this it might work it might not. The only real deciding factor is if I have to go axial flow pump. And that means most likely Hamilton. And to me that's like buying a Harley so damn expensive.

 

Lets run the figures motors (3) of them free. Boat I paid 2500$ I can sell the motors running no controls for a minimum 1000$ here in town, I already have people asking me if I want to sell them. So the hull 500$. Used sd312 jet, I saw one for sale for 2300$. Thats providing this jet will work. AT claims its good to 6700lbs. So if I can find another I should have under 5000$ into the boat thats with hull cleanup and paint and a new cabin

 

Sleep on it, imo. Take a look on the web at the hull shapes of jet-powered boats in your size range, and I doubt you will find one that is similar. Let us know if you do !

 

What about ib/ob