Does this add up?
 

I've finally had the chance to take a couple test runs on my new (to me) '98 260 Velocity, I'm new to the performance side of boating but the numbers just don't seem to add up. I'm running a 540ci (was told it was 600hp, but thats unverified) with a 1.5 drive ratio, I was running 72 on an older gps (78 on boat speedo) @5100 rpm wot with a new 28p Bravo 1 style (Cutting Edge) prop. I'm thinking I should be in the 5500rpm range wot? The boat planes out very easily with the 28pitch. Have also tried a Hydro QIV 26p with very similar results. I have no tabs or k-planes on the boat, and I'm still learning to drive through the porposing and chine walk at that speed so I'm sure that's affecting things. Should this boat be performing better? Prop issues? or just learn to drive it?

I don't know much about your particular model Velocity....but I'm fairly confident you should be going faster with 600 hp in that boat.....probably upper 70s to low 80s. By the way....what part of Ohio are you from and where do you boat?

You are right those numbers don't add up.
72mph GPS should be had with a 28p B1 at about 4600rpm.
My boat does 68 with a 26p B1 at 4650rpm.
As for 600HP in a 260, the boat should go well over 80mph with that much power.

Mostly Ohio river, Pike Island Dam pool, which is near Steubenville/Weirton

Interesting, if thats the case do I have too much prop slip?
I was plugging those numbers into a slip calculator and those numbers would come out at 11% But if a B1 28p is really a true 26p like I've read on these forums, that would be 5% slip. My numbers would be 20% or 14% respectively.

Bravo 1 props are about 1" shy; 28p is really about 27".

My boat is in the 10-12% range at 60mph.

We come down to the Ohio River a few times per summer.....we either put in at Kennedy Park or Toronto. We'll look out for a screaming 26' Velocity!

if you ever run up the ohio i am running a 260 with a 500efi up past pittsburgh

I'm running a 24' Advantage....ever make it down toward Kennedy Park area?

no never made it that far down, might take a long trip down this summer tho.