Mercury optimax 150hp top in speed

[CA]

I have a Procraft 180 combo fish and ski. This a heavy boat, the hull alone is 1650lbs. I run a 200 Optimax which weighs 528lbs. So I'm running a heavy rig. I run a 3 blader laser II 23 inch prop and still get around 65mph. I think you would gain a lot of spped with a three blade. Hope tihs helps.

[adam7456]

You top speed is going to depend on your RPMS, prop diameter, pitch, cupping, and number of blades.

To give you some more accurate information I need to know what your current RPMs run, the max RPM for your motor, the diameter of your current prop, and the pitch of your current prop.

Here are a couple general rules on props.

For each blade you add to a prop you can expect your RPMs to drop 150 to 200. Each blade you take away will increase your RPMs.

Similary going up in pitch 1" will reduce your RPMs by 150 to 200 and going down in pitch with increase your RPMs by 150 to 200.

Also a stainless steel prop does not flex as much as an aluminum prop so it gives a better bite. The general rule is if you have a stainless steel prop and go to an alumimum, your RPMs will increase the same as going down 1" in pitch. Going from aluminum up to stainless is like adding 1" in pitch to the prop.


Here is how it all plays together. I'll use some of your info in this example.

Let's say you have a 5 blade stainless steel prop at 26 pitch. If your wide open throttle, WOT, RPMs are 5,200 and your max RPMs for your motor are 5,600 then you have too agressive of a prop on the boat. You can drop 2" in pitch off the prop, a 24 pitch prop, and your WOT RPMs should go up to 5,600 giving you better performance. The prop will bite better because it is a lower pitch and will turn faster because the engine can run up to the specified max. Similarly you can drop from a 5 blade to a 3 blade prop and keep the pitch at 26 and your RPMs will go up to 5,600.

Now if your max RPMs are 5,200 and at WOT your motor is running 5,600 RPMs then you are under propped. You would need to increase your pitch from 26 to 28 pitch to bring your RPMs down to where they can safely run within the manufacturers specifications.

Now the general rule is adding extra blades, from a 3 to 4 blade prop, will slow down your speed due to the extra drag. That isn't necessarily true. When you are getting to that detail of props it all depends on the prop style, the pitch, the cupping, the prop venting, and who made the prop. Another factor is the prop slipping in the water. On my boat I had a 3 blade aluminum 21 pitch prop, the RPMs were 100 under the max. I switched to a performace style 4 blade stainless steel that was 19 pitch. The extra blade and stainless were to counter the RMP increase from dropping 2" in pitch. The 4 blade stainless prop ended up having better bite, got me on plane faster, and it ran about 4 MPH faster!

To get the max out of your motor it will require a lot of trial an error. There are prop calculators out there that take your current specs and speed and figure out how much prop slip you have, other calculators help you figure out who props should work. The results you should get on paper vs your actual results are 2 different things.

I have a ton of information on this. If you have questions just ask.

[CTFSHWHISKER]

talk to a reputable dealer who has set these boats up and they should eliminate a lot of trial and error,you are heavy with less than max hp if you have a 19 foot ranger. a trophy with the pvs vent system works great on rangers and you will probably get good holeshot and top
speed around 54-56 depending on what you haul start at 23 pitch.

[yogio]

I have a 18 foot nitro with a 3 blade, I think 23 degree lazer prop, and only a 115 merc... and I can do 53 mph...You should be able to get 60+ mph out of yours if I can get that out of my clunker.

[mattplapp]

For most F/S that size with a 150 you should be in the low 50's. Some of the 60's you saw on this board were from f/s's with more of a Bass Boat Hull than your boat. The ranger and Triton are on more of a Deep V or Multi-Species Hull than most boat companies which gives you better performance at low speeds (15-25) for skiing, but also gives you speed in the 50's.

Matt

[2ozone]

I have a 180 reata that came with a 150 v-Max. It has a 4 blade and will hit 60 (on a good day) with me only and a full tank. Runs 55 with no sweat.