How fast can I go?

[goodboy]

Hello everyone...

I'm not sure if this is the right place to post this but I'm wondering if anyone has any idea how fast this hull could go.

It's a 21 foot prowler boat by Cooper Yachts. I don't know the beam but I'll say that it's quite beamy lol. It's powered by a 4.3 and I'm looking to repower it with a 5.7 or maybe a 6.3 (383)

I understand all that's involved and understand I need a new drive... Just wondering what you guys think of the hull design. Really like the boat but it's just to slow lol. My goal is 50+

Thanks

 

[alldodge]

My guess is it will do 50 easy, probably get closer to 60. The other issues you should consider is, what is the max hp rated for the boat, can it be insured, and do you have the room to move the mounts. If you don't drop the hammer on it, you should be able to stick with the Gen 2 drive.

 

[goodboy]

Thanks for the response...

The boat was also available with a v8 and I have plenty of room for the motor.

Motor mounts look to be able to be moved but it's close and I may I may have to add some...

Good point on the max hp rating... Seeing as it was offered with a v8 I'm confident it's rated for 260hp but I have yet find the plate stating max hp..something I will look into..

As an experienced operator I agree that I might/should be able to make use of the r/mr drive (alpha gen 1) but understand that it's a very subjective subject as to its longevity behind 330+ hp and realistically I need to upgrade to a bravo drive...

I haven't pulled the engine serial number but I think it should be between 190 to 220hp... It does have a 4barell carb. Seeing as I want a top speed of 55 I think I'm going to need another 120 hp to get me there... Right now I get 45mph at 48 hundred rpm.

My worry was the design of the hull as it's different than anything I've seen on the lake... From what I've read having the pad on the keel (which it seems to have) is a plus... I don't want to overdue things and fight driviability issues like chine walk. Been there done that lol. Seeing as I'm building a custom engine if the consensus is the hull won't go faster than 50 without issues I will adjust my build... Hp isn't cheep so I don't want to build more hp than I need...

All I really want to cruse up to the cabin at 35-40 mph without having to use all of my available throttle... My top speed goal is not a desire to go that fast but more of a comfortable cruising speed that relates to my top speed goal.

Any more opinions?

Looks like an aggressive deep-v hull... Certainly not a speed hull lol

 

[ondarvr]

It's an I/O and over 20' so no HP rating applies, and insurance will cover just about anything, just tell them what you have.

 

[goodboy]

It's an I/O and over 20' so no HP rating applies, and insurance will cover just about anything, just tell them what you have.

Thank... That's some good info