On 21 Aug 2006 07:03:54 -0700, wrote:


wrote:
On 20 Aug 2006 18:37:49 -0700, wrote:


wrote:
On 17 Aug 2006 12:50:56 -0700, wrote:

I think you are optimistic. I only get 22-23 out of my 20' harris with
a 60 BF and I am pretty light, no furniture


You were right... took it out yesterday and only squeezed 13 mph out of
it!!!!! That was with four adults, two kids, and 2 1/4 dogs. Sound
right?

I was thinking 18 minimum.... so thinking I'd investigate a prop
change. Thoughts? Read something about a prop calculator.. but one I
found the link was dead and another charged for the service. Any real
world experience?


I am afraid you may be looking at it. If your boat is pretty heavy
(lots of furniture pottys etc) that does not surprise me. My buddy has
a 20' Crest that is stripped for fishing and it only gets 15-16 with a
40HP Suzi/Rude 4 stroke
Do you have a tach? That is the best prop calculator. You should be
somewhere in the recomended top RPM range at WOT Pontoons are still
never going to be speed boats. Does it sound like it is lugging or
over reving? (I doubt the computer will let it run too fast.)
If your dealer will let you swap out the prop it is worth a shot.
This is one calculator.
http://www.boatpropellers.com/propcalc.html

Thanks... but ugh. 13?! I wouldn't say there was a lot of furniture..
just a standard Sun Tracker "Party Barge". And it is one of the ones
with an aluminum floor and composite furniture (no plywood), would
think that would lighten it up a bit. Think it's 1600 lbs.

Turns about 4800 - 5000 rpms... figure that's about right. Doesn't
seem to lug or over-rev. Wasn't sure about several things, but guessed
4:1 on the tranny, 13 pitch prop, and 0.15 on the 'slip'.... sound
about right? Those figures came out 13mph.... so if my guesses were
right sounds like that speed is about right.

Brother-in-law is looking at a new one and the dealer is saying 32 with
a 90hp. Now I'm thinking that's way too high?


That sounds a little high. I have a 24' Bennington tri-toon with the
lifting strakes and underbody wave shield (performance package).
Bennington's are heavy, but it has a Johnson 150hp, and it does 35mph
when everything's right.