Retrofit Prout Quest with an outboard

[Proutquest]

Does anybody knows if this has been done? So remove the diesel engine, the Sonic Drive, cut a hole in the nacelle and then equip with a four stroke outboard?

Any obvious reasons not to do this?

[smj]

We removed the single diesel and twin hydraulic drives in our old Cherokee 35.
We then built a pod under the bridgedeck and mounted a Honda 50 outboard.
Worked great on the Cherokee, can’t see why it wouldn’t work great on the Prout.

[Proutquest]

Removing the diesel and changing with an outboard can be cheaper then renewing the Sonic drive leg. Also less noise and vibration and perhaps a bit lighter. Only worry I have is that the to be created hole in the nacelle might scope up water during sailing. I have never seen a Prout quest 31 with an outboard....

[atoll]

Originally Posted by Proutquest

Removing the diesel and changing with an outboard can be cheaper then renewing the Sonic drive leg. Also less noise and vibration and perhaps a bit lighter. Only worry I have is that the to be created hole in the nacelle might scope up water during sailing. I have never seen a Prout quest 31 with an outboard....

you dont cut into the underside of the nacelle ,you cut into the transom and mount the outboard in aproximately the same place and orientation as the old drive leg.
that way the outboard leg can be lifted when not in use,or sailing,a bilge pump should take care of any water that comes in over the transom

[sailingchiro]

Personally, I would mount twin outboards for docking and redundancy. I wouldn't put a steering mechanism on them, just use like a standard straight shaft. Lock them in place. Of course have them trim up while not in use. You could use two smaller outboards such as 2 25hp versus one 50hp. Less stress on transom and give the ability to park like a champ. I have Gemini that is docked behind me and it is docking by braille when he comes in. Catamarans like to go in a straight line and don't turn very easy going slow.

[Proutquest]

My guess would be that a single 15hp will be sufficient for the prout. Two 2 cylinder engines would add a lot of wheigt, two 1 cylinders is a bit underpowered and makes too much noise. Thanks for your replies.

[smj]

Originally Posted by sailingchiro

Personally, I would mount twin outboards for docking and redundancy. I wouldn't put a steering mechanism on them, just use like a standard straight shaft. Lock them in place. Of course have them trim up while not in use. You could use two smaller outboards such as 2 25hp versus one 50hp. Less stress on transom and give the ability to park like a champ. I have Gemini that is docked behind me and it is docking by braille when he comes in. Catamarans like to go in a straight line and don't turn very easy going slow.

That’s sad because a Gemini with a steerable outdrive should have close to the same maneuverability as twin screws, if they know what they are doing.

[smj]

Originally Posted by Proutquest

My guess would be that a single 15hp will be sufficient for the prout. Two 2 cylinder engines would add a lot of wheigt, two 1 cylinders is a bit underpowered and makes too much noise. Thanks for your replies.

Not sure where you are located but Yamaha has a new 25hp high thrust xl shaft that is fuel injected and light weight. Probably a perfect fit

[captstu]

Many folks with aging Gem outdrives have done the conversion. I put a 15 hp Merc long shaft on when I did my Gem. Good speed, approximately the same fuel economy (I flushed and reused my twin diesel tanks.)

The outboard puts out much less electricity (and smoke, grime and noise) than the old Diesel. I installed 2 large solar cells to make up for the reduction in electrical power and put a propane "instant on" in place of the heat exchanger. During the propane work, I found the old copper lines were cracking and replaced them all with acetyne-rated flexible lines that I had made up with fittings at a hydraulic shop.

It took two days out of the water and 3 days at dock to do the conversion. It was dramatically quieter, about the same speeds and I reused the steering connection so the engine turned with the rudder.

15 hp is not quite enough to enter an inlet comfortably against an outgoing tide.

If I were to do it again, I'd use a 25 long shaft - or for even better steering, I'd use twin 15hps.

With engine steering, docking is absolutely no problem - but I practiced for years so docking is not usually a problem anyway.

One gasoline caution. Here in Florida I can always purchase np-ethanol fuel. When I travel to a "drunken" state, I have to be absolutely sure to drain 1 tank so the two fuels don't mix. Drain 1, and refuel with drunken fuel. Run 2 until it is empty - and refuel that one.

The one time I mixed them I had a tank of phase separation fuel that would not run my engine - I had to drain the tank, drain the carb, and refuel before the engine would run.

[smj]

Originally Posted by captstu

Many folks with aging Gem outdrives have done the conversion. I put a 15 hp Merc long shaft on when I did my Gem. Good speed, approximately the same fuel economy (I flushed and reused my twin diesel tanks.)

The outboard puts out much less electricity (and smoke, grime and noise) than the old Diesel. I installed 2 large solar cells to make up for the reduction in electrical power and put a propane "instant on" in place of the heat exchanger. During the propane work, I found the old copper lines were cracking and replaced them all with acetyne-rated flexible lines that I had made up with fittings at a hydraulic shop.

It took two days out of the water and 3 days at dock to do the conversion. It was dramatically quieter, about the same speeds and I reused the steering connection so the engine turned with the rudder.

15 hp is not quite enough to enter an inlet comfortably against an outgoing tide.

If I were to do it again, I'd use a 25 long shaft - or for even better steering, I'd use twin 15hps.

With engine steering, docking is absolutely no problem - but I practiced for years so docking is not usually a problem anyway.

One gasoline caution. Here in Florida I can always purchase np-ethanol fuel. When I travel to a "drunken" state, I have to be absolutely sure to drain 1 tank so the two fuels don't mix. Drain 1, and refuel with drunken fuel. Run 2 until it is empty - and refuel that one.

The one time I mixed them I had a tank of phase separation fuel that would not run my engine - I had to drain the tank, drain the carb, and refuel before the engine would run.

Do you think you could get enough distance between outboards to make the Gemini able to have the twin screw maneuverability?

[mikedefieslife]

A engine like the Yanmar 3GM30 weighs roughly 150kg inc. gearbox. The sillette leg weighs a minimum of 56kg. So that is 200kg right there.

The Yamaha XL 25hp high thrust model weighs 70kg so even with two you are winning on weight. Unfortunately the 25hp has the worst reduction of all of the range. 2.08:1 vs 2.92:1 for 9.9 (51kg). Honda 15 also only has a 2.08:1 reduction and is 52kg. It has a 10" 4 blade prop, but the Yamaha can go up to 12". The diameter will make a big difference.

On the old Snowgoose 35 there are two methods of attaching outboards.
1) A single outboard in place of the old drive leg. Kept small this allows for a flush deck. Bigger (I've seen up to 50hp) and you need a box over it.
2) Either side of the nacelle and on the back of the cockpit lockers. 9.9s and 15s have been added here. Perhaps a 25 could squeeze in.

The Quest has more of flat nacelle transom and is flush with back of the cockpit lockers. So probably easier to use conventional outboard mounting, and build boxes on the rear deck to cover the tops of the motors.

[captstu]

SJM, I have seen twin Gem outboards attached two different ways. If steering optimization is critical, folks attach the bracket to the inside of the two transom sugar scoops, just inside the existing rudder cassette. This is how I would do it if I were starting again - that area is already re enforced by the factory to take rudder loads. A bolt on bracket like the URL below would need to be backed and further reenforced to take any shock load if you hit bottom (something we never do). This would steer with no difficulty, just center the rudder and use differential thrust.

Two engines centered would give less steering but would provide backup in case one failed. With twin 15 long shafts, one could be shut down on long trips to save fuel.

https://www.walmart.com/ip/Panther-4...hoCuEwQAvD_BwE

[CapnBazza]

Our Endeavourcat30 has an aluminium articulated pod which supports a 60 hp 4 stroke Yamaha. The motor is linked to the steering which gives very good low speed manoeuvrability- basically, in reverse you point the motor and the boat follows. The articulation in the pod is redundant because the motor has tilt (the design called for a 25hp Honda without tilt). There is very little cavitation with our setup and it works very well. You should see how clean and devoid of barnacles the prop is.

[mikedefieslife]

The Quest is a very different shape to the Gemini and Endevour and even Catalacs. All have either rear transoms, or sugar scoops so there is little use looking at any of those really for inspiration. Best look at other Prouts there are images around, even on these boards.

[Proutquest]

Hi mike,

Can you share a link to an example of a Prout Quest with an outboard? I cannot find one and I did tried various search engines and fora.... Very curious to see since the Prout indeed has a different shape when it comes tot the stern/nacelle..