Am I using the best prop?

[Old No 7]

I need to buy a spare prop, (Or change my current prop to a spare).

My current prop is a Mercury Black MAX 13 3/4 x 15 aluminum prop

My Boat is an Angler 18' CC 2007. The weight is 1600lbs

The motor is a Mercury Optimax 90HP 2 Stroke also a 2007

I nomally have 2 -4 people on the boat and try to keep 1/2-3/4 of a tank of gas. (40G tank)

At a WOT of about 4500 I get to 35 mph. The WOT is from what I remember from last year. The boat is not in the water yet.

With just me on the boat in flat water I can get to 40 mph.

I typically run from point A to point B. on the bay off long island NY. I also do alot of fishing, but I typically get to my spot and drift.

Hopefully thats enough info. Is there a better prop I should be using?

Than ks for tyhe help!

Mike

 

[wildspeed]

Re: Am I using the best prop?

Surprising that you only get 4500 with a 15 pitch
Do do you have an hydrafoil installed ? At what height your engine is mounted ?
Is your engine running on all cylinders ?

 

[steelespike]

Re: Am I using the best prop?

Loaded speed seems good rpm may be a little low.
Your light load speed is good;what is the rpm?I have to wonder if the speedo is optimistic or tach is reading low. Has the height of the motor been fine tuned?
Raised to a point just before ventilation(cavitation) becomes a problem.
Can you do a gps speed check?Get us a fresh test speed and rpm.

 

[Old No 7]

Re: Am I using the best prop?

Sorry I gave some bad RPM info: I put the boat in the water today and went for a ride

I was way off onn the RPMs I hit 5500 with just me on the boat and a full tank (40gal). Max speed was 38mph. (Pretty choppy today on the water.

Thanks!

 

[wildspeed]

Re: Am I using the best prop?

Those corrected # sound pretty good.....

If you want a spare prop and you don't have too much hard bottom/rocks, you could try a SS prop

 

[Old No 7]

Re: Am I using the best prop?

I stay in the bay and once in a while on calm days venture out into the ocean. The bottoms are pretty much sand and mud.

Will I gain much with a SS Prop?

 

[steelespike]

Re: Am I using the best prop?

Unfortunately I don't have the expertize to estimate the improvement to ss.Hopefully someone will be along with more expertize.Some don't believe the change to ss is worth the investment.
Usuually need even more specific info.When going from al to ss the change can be unpredictable.If you are just buying a spare And you want to shoot for a real difference try a 4 blade in the same brand.14" pitch.This will give an improved hole shot and stay on plane with less power and fiddling.With your sometimes rough conditions this may be a help.If you can find a dealer that will let you try props with the intention to buy Thats probably the best way to do a change to ss.

 

[Old No 7]

Re: Am I using the best prop?

Ok Thanks,

I think i'll try the 4 blade 14" pitch prop as you said. It does take a bit longer for me to get up on plane that other boats I've watched. (Similar boats)

Mike