Looking for more power next season, advice required on replacing Perkins 4.108.?

[RobWales]

I have a single shaft driven Jeanneau Esteou 630 (6.3m planing hull hard chine) fishing boat which I bought at the start of this season which has served me very well, however I would like to upgrade the performance over the winter by replacing its existing Perkins 4.108 which runs through a ZF 25 M gearbox.

I'm told that this current setup pushes out something in the region of 40hp?...which has given a max speed of 13 knotts(bottom clean and shiney prop at start of season) showing on my gps, she rides at this speed bows up but I'm afraid she is too underpowered to climb over the hump and onto the plane!

I'd like a max speed of circa 18/22 knotts with a cruising speed on the plane of which I guess to be approx 15/16 knotts?

I have a limited budget and I believe the current box will take 100hp max...

So my question to the experienced here is what engine would you reccomend I replace the Perky with?

Many thanks in advance.

 

[Stemar]

I've often thought that a car engine from a breaker would be a cheap option in the 50-80 HP range. Most cars seem to die of expensive MOT repairs before their engines are knackered. My Focus has 170,000 miles on the clock and I still don't put any oil in between changes.

However, I've no idea what the marinisation costs would be. By the time you've sorted out a wet exhaust and adaptor plate to hook up to the gearbox, it may not be so cheap. Lancing Marine would be my first stop for info about that.

 

[Jcorstorphine]

Look at your prop and gearbox first.

I have a single shaft driven Jeanneau Esteou 630 (6.3m planing hull hard chine) fishing boat which I bought at the start of this season which has served me very well, however I would like to upgrade the performance over the winter by replacing its existing Perkins 4.108 which runs through a ZF 25 M gearbox.

I'm told that this current setup pushes out something in the region of 40hp?...which has given a max speed of 13 knotts(bottom clean and shiney prop at start of season) showing on my gps, she rides at this speed bows up but I'm afraid she is too underpowered to climb over the hump and onto the plane!

I'd like a max speed of circa 18/22 knotts with a cruising speed on the plane of which I guess to be approx 15/16 knotts?

I have a limited budget and I believe the current box will take 100hp max...

So my question to the experienced here is what engine would you reccomend I replace the Perky with?

Many thanks in advance.

I would look at what prop is installed in the boat at the moment and also look at your gearbox to see the reduction ratio. is, Then with the data, log into one of the Prop Calc sites such as Prop Calc or Surfbaud.

Enter in your present data amd see where you get to. Also see what diameter of prop you can swing etc.

Just sticking in a bigger engine may not make you go any faster if you cant get the prop matched.