21' superboat prop question

[screamindemon]

What the best prop for top end speed on a 21' Superboat Legend w/a Merc 2.5 280, with 12" of setback.

Currently I'm running a 24 and 25 trophy to the high 70's via gps, but that's it...

THanks!

[Still Crazy]

What gearcase are you running?

[SUPERBASH]

-What is the exact # in GPS terms? High seventies means 77- 78- or 79 to me which is as good as its gonna get.
A Chopper prop will give you 2-3 mph over a TrophyPlus.
With a 21' SB...a 1-2' chop will air out the hull & yield a higher top speed than flat water.

Are you still running the sportmaster??? If so...
-What gear ratio in your sportmaster. 1:62's or 1:75's ?
-How do you like the way it handles with the sportmaster ?
-What are your rpm's ???
-What is your propshaft centerline?

*I looked thru your old posts. In 2004..."wide open trimmed out"... you were doing 71 @ 6000rpm.
What has changed since to make the improvement in speed?
http://forums.screamandfly.com/forums/showthread.php?t=64901

http://img89.imageshack.us/img89/9008/sasmokin3tg.gif (http://imageshack.us)

[viper15]

That boat should go easily in the 80'S. An ET will work good but I was told A mazco RE4 runs Real good on these. How High is your motor? In 1988 My friends went 78-82 with a 2.4 bridge port. The boat was still rinning 2 years ago and then sold. with a tired motor and 4 people fuel and a cooler. it still went 75 on gps it was rigged BY East coast Marine. There is more left in your boat.

[SUPERBASH]

In 1988 My friends went 78-82

Let me guess....

-"A cop clocked my friend with radar"
-"Thats what it read on my friends Keller speedo" http://img212.imageshack.us/img212/9293/bash3lo.gif (http://imageshack.us)

[baja200merk]

Let me guess....

-"A cop clocked my friend with radar"
-"Thats what it read on my friends Keller speedo" http://img212.imageshack.us/img212/9293/bash3lo.gif (http://imageshack.us)
LOL!
bash i read throught your posts looking for comments like his :D

[viper15]

Don't be jellous Bash!!! I finally bought a boat and put my project 21 on hold. I'll be back out on wednesdays.

[SUPERBASH]

HeHeHe !!!http://img61.imageshack.us/img61/8342/sgrin3dv.gif (http://imageshack.us)
( What "new" boat did Frank buy ??? )

[Dave S]

Is not any better than a Keller....... The Keller told me I was SLOOOW.:( The GPS costs too much to tell me the same thing. Buy beer and make belive.:D

[jerry]

Let me guess....

-"A cop clocked my friend with radar"
-"Thats what it read on my friends Keller speedo" http://img212.imageshack.us/img212/9293/bash3lo.gif (http://imageshack.us)
he was running next to hoser HAHAHAHAHAHAHAAH!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

[screamindemon]

Bad wire shorting out the fuel pump.

As for top speeds, I'd really have to recheck. Been running both a 24 and 25 trophy, and getting varying numbers depending on the length of the run, water, and wind conditions.

I'm still runing the sportsmaster, not sure what the gear ratio is, but I would imagine whatever comes standard.

Anyway, it sounds like I'm getting all I can out of it, or pretty close to that anyway, so further adjustments might not be worth the effort...

I seem to hear higher numbers from what I would consider similar boats & configurations, which got me wondering what other changes I could make to get into the mid-eighties or even better. To that end, I thought the biggest bang for the buck would be in prop selection, moving from a 4 blade Trophy to a 3 blade.

[jerry]

About 80 Will Be Top Speed For That Setup

[SUPERBASH]

Is this the boat ? The only thing that confused me was Your transom was solid red ? Re-gelled maybe?
http://img522.imageshack.us/img522/4831/21twinsmediumsmall4np.jpg (http://imageshack.us)
Anyway...As I said in the past. That boat was rigged new with a single 200 it wasnt that fast.....so then it was rigged with twins. I was in it. Then sold to 2.5 21 Bill.

[screamindemon]

I don't think that's the boat, the transom doesn't look re-gelled., at all....I'm curious how the boat ran w/that much weight & HP back there, and of course, at what speeds.....

[SUPERBASH]

It launched like a raped ape & did mid 90's with the twins ( back then) .....but was a handful at speed.

- 2.5 21 Bill ran it & put the single back on it.
http://img194.imageshack.us/img194/7779/2120right4mz.jpg (http://imageshack.us)

[RIVERRUMMER 70]

Let me guess....

-"A cop clocked my friend with radar"
-"Thats what it read on my friends Keller speedo" http://img212.imageshack.us/img212/9293/bash3lo.gif (http://imageshack.us)
THE WORLD OF ACCURATE SPEED DID NOT BEGIN AND END WITH GPS YOU
BOZO! PULL YOUR HEAD OUT OF YOUR A$$ AND TRY TO BE A HELPFULL
PAL INSTEAD OF A SMART ASS KNOW IT ALL!
IF YOU GET OFF ON RIPPIN PEOPLE TRY IT SOME TIME TO THEIR FACE IN PERSON, YOU HIDE BEHIND YOUR KEYBOARD AND SPOUT OFF CRAP.
IF YOU DONT LIKE OR BELIVE OR KNOW DIFFERENT SHARE IT IN A CONSTRUCTIVE FASHION, PEOPLE CAN RESPECT CONSTRUCTIVE RIPS NOT
A$$HOLE SMART ASS CRAP.:mad:

[baja200merk]

THE WORLD OF ACCURATE SPEED DID NOT BEGIN AND END WITH GPS YOU
BOZO! PULL YOUR HEAD OUT OF YOUR A$$ AND TRY TO BE A HELPFULL
PAL INSTEAD OF A SMART ASS KNOW IT ALL!
IF YOU GET OFF ON RIPPIN PEOPLE TRY IT SOME TIME TO THEIR FACE IN PERSON, YOU HIDE BEHIND YOUR KEYBOARD AND SPOUT OFF CRAP.
IF YOU DONT LIKE OR BELIVE OR KNOW DIFFERENT SHARE IT IN A CONSTRUCTIVE FASHION, PEOPLE CAN RESPECT CONSTRUCTIVE RIPS NOT
A$$HOLE SMART ASS CRAP.:mad:
bash is sorry your right a teleflex speedo is way more accurate then a keller http://www.websmileys.com/sm/obscene/eck32.gif

ur breakin his balls meanwhile your post didnt contribute to this thread either! when did the world of accurate speed begin? http://www.websmileys.com/sm/violent/sterb151.gif

kevin http://www.websmileys.com/sm/obscene/eck05.gif