prop question
 

I have a 25' with a 270hp 350cu Emi thunders
Corsa Quick and Quiet II and a 1.5 ratio drive 21 pitch Laser II turning 4600 rpm I attain 50.5 gps with one adult male 210lbs 3 females 115lbs each average and 3/4 tank fuel about 60 gals 3 gals water boat weight of 3900 dry 8' 3" beam, stepped hull
deadrise 18 degrees and transom angle of 12 degrees

cruise is 3800 rpm 40mph
3950 rpm 42.5mph
corsa has about a .7 mph gain in the open position

? prop recommendations the slip is higher than I like
close to 17% and I have to trim down quite a bit to keep the speed up

Re: prop question
 

Where is the question?
You could always trow the 3 chicks overboard that would gain some mph but then your wallet would get heavier!!!:D

prop question
 

I think he is bragging about the 3- 115lb chicks.:eek: :D he is not thinking props :D :D

call if we can help just playing around.;)

? prop recommendations the slip is higher than I like
close to 21%

Guys, Was it to late for you last evening? Leave that board and get some sleep after 10 PM... You are running after a divorce ;-)

TOP DJ : I think I know what your question is...

Darin, correct me if am wrong, you are the prop expert.

Is'nt a laser II a pretty small diameter prop for a 25' 3900 pounds boat?
That would explain is 21% slip... Maybe he should go with a mirage. 2-3 mph gain?

If the laser prop has vent holes you need to plug them. The next option would be a mirage but you may need a little less pitch. a mirage plus will knock off a few more rpms so a 19 in the plus would be about right to keep the same rpm's good luck

ttt

I've been working the slip issue myself. Look at extra weight in the boat. Look at trim and the way the boat rides at WOT (bow high or stern high). Look at the condition of the hull bottom (dirty, wax, hook in hull. Look at the x dimension.

What does the boat run lightly loaded (rpm and mph)? With your numbers and a 12% slip you should see 56.0mph.

BT :cool:

WWW.TOPDJCOM/Thanks
 

THANKS for the order ? And, we will get you fixed up:cool: Darin:)

well I got under it and the hull looks like it was just pulled from the mold, so I dont think thats the problem.
Im sending my prop to Houston Props in a couple weeks
Im gonna get some more good readings this weekend
with 1/2 tank and 2 adults

the max the boat could really go at that HP and weight would be
56, so Im close to the limits of the combination.

Have you come across any used 27p, labbed mirages for me yet Darin? Been shopping for some in the seven to eight hundered dollar range for the pair.

Dave

labbed 27's mirage props
 

Dave send me your contact number and best time to call you,and I will do my best to get you fixed up/Darin
Houston Propeller on Kuykendahl rd:rolleyes:

I forgot to tell you , I have to trim almost all the way down to get it to 50 mph if i trim up the slip skyrockets, some poeple are telling me to get a mirage because of the larger diameter
will let me trim up, got any Ideas

prop/TOPDJ
 

When the prop arrives, I will call you,also Iron man, might just be right? we will see what can be done with yours first and go from there .none the less the prop will be alot better and if you come across a 19 mirage plus to try, It would be worth it to try. Talk to you later /Darin;)

new numbers 2 people 7/8 tank
4600rpm 52mph
4000rpm 44mph
3600rpm 38mph

still cannot trim it out , blows out easy

LOAD CHANGE'S SPEED
 

WE HAVEN'T WORKED THE PROP YET,but as you can see how the load factor really changed the numbers,;) have a good 4th JULY AND we will look for the prop after the big BANG!:D

yes your right and I just found that I read the tach wrong
Im running with 1/2 tank 2 adults a 4600Rpm
52.5 mph gps on pretty smooth water
the silent choice I have , mine is the reverse type No power = thur hull, It helps a lot to plane quicker with it on or thur Hub
then once on plane turn it off and the diverters open for a gain of .7mph


I'll be leaving them vent holes, seem to be good for the holeshot
when in thur hub mode

the numbers after Darin worked this used prop back to shape
OLD could not plane at low speeds
New I can plane all tha way down to 28mph
Old 3000rpm 30 mph
new 3000rpm 34 mph

Old 3600rpm 38mph
new 3600rpm 41.5mph

old 4000rpm 44mph
new 4000rpm 48mph

old 4600rpm 52mph
new 4500rpm 53mph*

improved lift and ride.

now I just need more horses to turn a little more RPM