Optimax 150 checkmate predictor 16.5'

[Hypper]

Hi

Need some help on this...

Have an old checkmate predictor 1988
And a Mercury optimax 150 hp

Have not yet have time to test boat and motor
Together.. Overhaul is taking all my time

Need some data on the hull
An what could be the optimal prop
For the boat...

 

[wired]

Hi

Need some help on this...

Have an old checkmate predictor 1988
And a Mercury optimax 150 hp

Have not yet have time to test boat and motor
Together.. Overhaul is taking all my time

Need some data on the hull
An what could be the optimal prop
For the boat...

What sort of hull data do you need and what do you want to do with the boat? ski, speed, fish etc.

 

[chrispallen]

do you have a jackplate or are you bolted right on the transom? I have a 5 or 6 inch jackplate and an old teardrop CLE lower, and can run the propshaft even with the pad. I have a 26 trophy that was sent to merc racing to be labbed, but you would probably be good starting with a 24. I was also running a 150, but it was an XR-2

hope that helps, there are a few guys here with very well set up predictors that can give advice.

 

[Hypper]

What sort of hull data do you need and what do you want to do with the boat? ski, speed, fish etc.

Hi I mean data like when the boat was new

And a manual know that this may not be around...

 

[Hypper]

do you have a jackplate or are you bolted right on the transom? I have a 5 or 6 inch jackplate and an old teardrop CLE lower, and can run the propshaft even with the pad. I have a 26 trophy that was sent to merc racing to be labbed, but you would probably be good starting with a 24. I was also running a 150, but it was an XR-2

hope that helps, there are a few guys here with very well set up predictors that can give advice.

Hi

Don't have a jack plate.. I have in minde to make this
My self..

My idear is some high speed and some ski
I know I may need 2 props this is okey

For now the motor is on the transom for now
If I use a jack plate I think that I will get some
Problems with the stock water intake on the lower gear

For now I am making a centre or front tank to keep
The weight down in the back off the boat

 

[wired]

You do not want to move weight to the front of the boat. It makes handling unstable and high speed handling very unstable. V pad style boats such as these need the center of gravity as far back as possible. The goal is to generate enough lift at rear of the boat to rise up on the pad past 45-50 MPH or so. Hard to do that when you are fighting the weight in front. It is not a displacement hull boat. Take a look at my avatar. That is the ideal stance at higher speed.

As far as owners manuals even if there was one originally it wouldnt have anything useful in it. Boat manuals in the 80's consisted of life jacket warnings. A 19 pitch 4 blade is a good starter prop that will get you into the 50's.

 

[jumbofordman]

You do not want to move weight to the front of the boat. It makes handling unstable and high speed handling very unstable. V pad style boats such as these need the center of gravity as far back as possible. The goal is to generate enough lift at rear of the boat to rise up on the pad past 45-50 MPH or so. Hard to do that when you are fighting the weight in front. It is not a displacement hull boat. Take a look at my avatar. That is the ideal stance at higher speed.

As far as owners manuals even if there was one originally it wouldnt have anything useful in it. Boat manuals in the 80's consisted of life jacket warnings. A 19 pitch 4 blade is a good starter prop that will get you into the 50's.

I run my Predictor with a 2 bags of concrete in the front, it actually runs much smoother and more stable that way. As to the prop, unless the Optimax gear ratio is vastly different than other Merc outboards, that's going to be way off. I run a 21 pitch on my 115, and ran a 25 pitch with my V150. I'm also going to suggest a jackplate, I think it has the biggest bang for the buck on speed.

 

[wired]

It will seem smoother until it does the bat turn at 70 MPH. If the steering is good ( TIGHT ) you wont have stability ( chinewalk ) problems at higher speeds. Keeping the bow flat on the water robs speed. Scooting along just on the back of the pad will easily gain 10+ MPH over hugging the water. Motor cant budge a fraction of an inch side to side though.

I ran 54 MPH for years with a 19 pitch and a Johnson 90. Under 20" pitch being much better for skiing and other water sports stuff and unless the boat is built to handle it its really not safe to go over 60 MPH anyway. 25 pitch on a 150 and you are either slipping like hell or you arent getting into the power band. With a 7-8% pitch slip 26 chopper you can run 85 MPH at 7200 if you have the power to push it.

 

[Hypper]

Hi

Can see my prop on the motor is a 15 1/4 p15

I found a 14 1/4 p23 I think I will start on this
And make this my set point for test.

Regarding the weight I don't want to set all in the front
More in the bottom of the boat.

If I look at it the boat is 400 kg an motor 200 kg an a tank 150 liter = 150 kg
This will make the boat backend heavy... And if I hit a wave it will fly
And landing heavy on the back not fun

In my old for fun raceboat winrace/brømo I move battery and tank forward this
Was a complet new boat to sail and better handling... Don't want too add more
Weight like the cement bags... I made a test like this with water bottles I put them some different places in the boat and it worked better handling bud my
Top speed did go down....

 

[Hypper]

Hi

Found the data
http://checkmate-boats.com/photopost/

 

[Hypper]

Hi

now I got time to test my boat and motor, have to say it is crazy.
but it's heavy in the rear end, then started moving weight forward in the boat

first the battery 100 Ah 353x175x190mm 810cca 23,8 kg

http://www.baadgalleri.dk/fotoalbum/diverse-baad/6978-checkmate_predictor_16_6

 

[Hypper]

Nice test today, full power on the optimax is 88 km/t =54 mph
Prop is a p23 3 blade standard no slip it jumps right out of the water

The battery in the front is giving more stability
Before I cut not trim the motor up any the boat became unstable

Need some help

Prop size now
Jack plate with more angel then transom
8" or 10" jack plate
Fixed trim taps will this give more stability

 

[Hypper]

Video some chinewalk

http://www.baadgalleri.dk/video/diverse-baad/3311-checkmate_150_optimax

 

[DropTop5.0]

Is your steering tight? You should not be able to move it left to right.

 

[Hypper]

My steering tight hydraulic with engine lock valve