Presuming your tach is working ok the next thing you need to know is wot
rpm. If you have a light load when you test then closer the the 4800 is
preferred. I believe the rule of thumb is 200rpm per inch of pitch. I
agree 10 is improbable. But 17 is not way out of line. There is no
"general" cruising and top speed for boats in that range, it will all depend
on the engine and prop. I suspect that boat was also available with a big
block. What is it about the performance you unhappy with? You mention the
time to get on plane as being slow. A higher pitch will not improve that,
in fact it will be even slower getting on plane with a higher pitch prop.
Boats are "single" speed so you are always striking a balance between hole
shot and top speed. If you think it is under pitched and has trouble
getting on plane the original owner may have deliberately used a lower pitch
prop to help with the hole shot. Tabs are a good addition. Power is a
personal thing but it's been my observation that engine size is the first
thing that suffers when the manufacturer is trying to keep the price down.
For me I'd have to have a 454 in a boat that size, or two 350s. You may
tweak the performance some with prop changes but don't expect miracles. The
local supplier may have a "try before you buy" policy on props which would
let you try a few out. Another good option is to buy used on ebay and then
sell the ones that don't work out. Used props hold their value. You'll
just be out a little shipping and long as you don't overbid on one.

wrote in message
oups.com...
Everything is 1988. Engine is in mint shape, I've had a compression
check and inspection done. (I know how to do it myself but when I
bought it I talked to the mechanic who checked it over)

The hull length is actually 26'5" but with pulpit it's 28'2".

Beam is 8'3" and weight is 5900lbs.

I'll play around with it soon and check the numbers. I know when I
went out with the previous owner during the sea-trial we'd kick the
RPM's down because they did seem to jump but I don't remember how high
they went.

WOT range is supposed to be 4400-4800 but I believe it was running
higher.

So let's go with a 26' cruiser. What is a "general" cruising and top
speed for a 26 foot hull length cabin cruiser with single engine? I
know hull design and beam make a big difference, but I'm looking for
some ball park numbers.

With the 14.5x17 according to his logs, gas mileage ranged from
1.5-1.9 depending on passengers and weather conditions. In 4-5' waves
it did not stay on plan and dropped to 1.1MPG.

I've been using online calculators but they all show a pitch of 10!!
I even plugged in other boat/engine configuration, it also recommended
a pitch of 10 for a Sea Ray Sundancer 260 so I'm not sold on it being
accurate.