How much HP needed to get 38' to 100 mph?
 

Thought I'd ask this question as I have no idea.

2003' 38' Top Gun with Bravos. How much hp is typically required to get the boat to 100 mph?

Customer has one with pro charged engines claiming ~900 hp and does right at 100 mph. Can this be right?

If it really has 900 hp then that would be right.......

My Formula 382 had 500 EFI's with 8 psi Prochargers when I bought it. They claimed 830hp, Precision Marine claimed to have dyno'ed several at around 790hp. The Formula is probably 6-8 mph slower than the TS Top Gun.....I saw 95mph, supposedly the boat ran 98 when it was first built. I bought it used and have since taken the Prochargers off the motors ... only ran it WOT once.

our 2006 38 Top Gun does 92mph with 600 mercs. 700s in a 39 does anywhere between 102-106mph. So 700 would be a good estimate. Don't count on those bravos holding together for very long with 700+hp running through them though.

How similar is the 39' to the 38' Top Gun?

700 and the right props and its should do it

CORRECTION: It's a 2003' 38' Top Gun, not a 2006'.

Here is why I ask.

They tell me:

Now we have the power of 850 horsepower. Top Gun 38 has the gear ratio 1.5:1 We use propellers Maximus have five blades. diameter of 15 1 / 4 X 32 inches with Sport Master lowers.

But last season we achieved record at ratio 1:1,26. on the propeller Hering 15 - 5 / 8 Which had six blades and step 30 inches. Then, our speed was 102 miles. Engines was 920 horsepower. But it was risky. BRAVO broken six times.

A power cut up to 820 horsepower for reliability. Speed boats with these conditions, equal to 92 miles per hour. Engines have a turnover in 5400

Then they Blew the engine, broke rod and a piston. Seems it should have been faster??

So, they wanted a change from Bravo's since they pulled the engines and had to rebuild them. They dyno'd at 734 they tell me.

I do not, nor do they as there are no markings on them, know the propeller pitch with the change. First time in the water the boat runs 100 mph now with the lower hp setting.

I think this seems more realistic but didn't know what it should be doing in the first place.

Wonder if it was a drive failure that made it barrel role??

It's a bit cold in Moscow this week, so no more sea trials this year. (they converted the boat in about one week) and only had the insanity to run it in winter once. The boat runs the same speed with lower hp than before so this is a positive note for the first sea trial.

?? That was before they had contacted me. They all went swimming they told me.