Changing from inboard to outboard.

[Finnmaster6400MCgreenland]

Jan.
Invested in a Finnmaster 6400 MC Cruiser late last year, previous owner informed that the motor (inboard Mercruiser 1.7 120hp w. Alpha drive) did start but had issues. Shipped the motor to DK for assessment (I live in Greenland) and the guy concluded that a piston was blown. Between spare-parts being hard to find and contemplating that 120hp was a bit too weak, a decision was recently made to invest in a Suzuki df175apx outboard motor.
This is the lay of the land at the moment. Well knowing that the transom needs re-modeling to hold the outboard. Fortunately, I made exactly similar arrangements on a previous boat.
Update:
May.
Transom stiffened, motor and new steering installed. Cleaned and flushed fueltank.
Boat basically finished and ready for launch, just basic maintenance and small repairs, like new wipers, changing some bulbs, giving everything a vacuum and a wash (everything is dustet with glasfiber-dust from sanding the reinforced transom). Added a Lowrance GPS and expect to fiddle arround with some nmea2k connections to the motor (Winter).
There is a remote controlled spotlight that needs some work, and pulling a new ground to the hydraulic pump for the flaps.
But still want to add a few things later, a diesel heater (old heating system depended on hot water from the engine), gas stove, new speakers and maybe add some interior LED lighting.

 

[simonfraser]

excellent project, ask the moderator to move this to the motor boat forum
Motor Boat Forum

 

[William_H]

I hope it all works well for you. I had a friend who had a 25ft mobo. It had a Mercuiser V8 with contra rotating props inboard to a stern leg. He got a deal where he traded in the V8 for an out board I think Mercury again. A very successful change with quieter better fuel consumption more space and the ability to raise the moror out of the water. A voluntary swap but but very successful. ol'will

 

[LONG_KEELER]

Excellent pics .
Nice project .

Did you have to re-work the ballast much ?

 

[Rappey]

I did similar but on a much lesser boat. I opted to bolt a frame to the rear to mount the outboard so avoided cutting into the transom and cockpit.

 

[Moderator]

Thread relocated from PBO.

 

[Bigplumbs]

Incredible work well done. So offten on here when asked people tend to say it is not possible but it obviously is

 

[limecc]

Ideal candidate, great job and thanks for posting!
Here's a link to another outboard conversion (currently ongoing):

 

[Finnmaster6400MCgreenland]

Jan.
Invested in a Finnmaster 6400 MC Cruiser late last year, previous owner informed that the motor (inboard Mercruiser 1.7 120hp w. Alpha drive) did start but had issues. Shipped the motor to DK for assessment (I live in Greenland) and the guy concluded that a piston was blown. Between spare-parts being hard to find and contemplating that 120hp was a bit too weak, a decision was recently made to invest in a Suzuki df175apx outboard motor.
This is the lay of the land at the moment. Well knowing that the transom needs re-modeling to hold the outboard. Fortunately, I made exactly similar arrangements on a previous boat.
Update:
May.
Transom stiffened, motor and new steering installed. Cleaned and flushed fueltank.
Boat basically finished and ready for launch, just basic maintenance and small repairs, like new wipers, changing some bulbs, giving everything a vacuum and a wash (everything is dustet with glasfiber-dust from sanding the reinforced transom). Added a Lowrance GPS and expect to fiddle arround with some nmea2k connections to the motor (Winter).
There is a remote controlled spotlight that needs some work, and pulling a new ground to the hydraulic pump for the flaps.
But still want to add a few things later, a diesel heater (old heating system depended on hot water from the engine), gas stove, new speakers and maybe add some interior LED lighting.View attachment 135330View attachment 135331View attachment 135332View attachment 135333View attachment 135334View attachment 135335View attachment 135336View attachment 135338View attachment 135339View attachment 135340View attachment 135341

Update:
Jan 2023
Had a short first season in the water a couple of weeks last summer, tested the transom and drove the motor in. Everything seems to be in order but expected a couple of more knots at the top, wot at 37-ish and cruise at 27.
Still a few bits and bobs to tidy up but quite happy with the build. Expect to try her out again at season-start Easter time.

Jan.
Invested in a Finnmaster 6400 MC Cruiser late last year, previous owner informed that the motor (inboard Mercruiser 1.7 120hp w. Alpha drive) did start but had issues. Shipped the motor to DK for assessment (I live in Greenland) and the guy concluded that a piston was blown. Between spare-parts being hard to find and contemplating that 120hp was a bit too weak, a decision was recently made to invest in a Suzuki df175apx outboard motor.
This is the lay of the land at the moment. Well knowing that the transom needs re-modeling to hold the outboard. Fortunately, I made exactly similar arrangements on a previous boat.
Update:
May.
Transom stiffened, motor and new steering installed. Cleaned and flushed fueltank.
Boat basically finished and ready for launch, just basic maintenance and small repairs, like new wipers, changing some bulbs, giving everything a vacuum and a wash (everything is dustet with glasfiber-dust from sanding the reinforced transom). Added a Lowrance GPS and expect to fiddle arround with some nmea2k connections to the motor (Winter).
There is a remote controlled spotlight that needs some work, and pulling a new ground to the hydraulic pump for the flaps.
But still want to add a few things later, a diesel heater (old heating system depended on hot water from the engine), gas stove, new speakers and maybe add some interior LED lighting.View attachment 135330View attachment 135331View attachment 135332View attachment 135333View attachment 135334View attachment 135335View attachment 135336View attachment 135338View attachment 135339View attachment 135340View attachment 135341

Had a short first season in the water a couple of weeks last summer, tested the transom and drove the motor in. Everything seems to be in order but expected a couple of more knots at the top, wot at 37-ish and cruise at 27.
Still a few bits and bobs to tidy up but quite happy with the build. Expect to try her out again at season-start Easter time.

 

[DavidJ]

Apart from everything else I was impressed the way the cut down bathe platforms look so in keeping with everything……..it was probably the easiest part of the whole job!

 

[Commercial Dave]

How much does that boat weigh and what prop have you got on the motor? The DF175 is a lovely outboard, I did my training in a 7.5m RIB with one. I can't believe how smooth and quiet it is...at idle from the helm seat you can't hear it. Quite a few times I had to look at the rev counter to check it was running! Had the electronic controls too, I think Suzuki call it Precision Control, and it's the greatest thing ever. But it only did 32 knots flat out...

 

[QBhoy]

Nice job there. Looks like the set up for engine height was a close one there. Did you just about get away with it in the end ? What prop pitch and rpm are you running at 37 knots ? Not to be sniffed at, but think you’re right and she could see a little more. That’s why I’m asking about the engine height really. Was wondering if she vents easily with trim and if so, can it be compensated with a prop thats designed to hold its grip near the surface.

 

[Finnmaster6400MCgreenland]

Nice job there. Looks like the set up for engine height was a close one there. Did you just about get away with it in the end ? What prop pitch and rpm are you running at 37 knots ? Not to be sniffed at, but think you’re right and she could see a little more. That’s why I’m asking about the engine height really. Was wondering if she vents easily with trim and if so, can it be compensated with a prop thats designed to hold its grip near the surface.

It runs 6100 rpm at wot, and it came with following prop.

 

[Finnmaster6400MCgreenland]

How much does that boat weigh and what prop have you got on the motor? The DF175 is a lovely outboard, I did my training in a 7.5m RIB with one. I can't believe how smooth and quiet it is...at idle from the helm seat you can't hear it. Quite a few times I had to look at the rev counter to check it was running! Had the electronic controls too, I think Suzuki call it Precision Control, and it's the greatest thing ever. But it only did 32 knots flat out...

Fully loaded it should be a bit over 2 tons, and the following prop came with the motor.