Switching the inboard for an outboard.

[okawbow]

I dropped the pan off my 43 year old Albin diesel and discovered worn bearings and cylinders. I am weighing the pros and cons of taking out the diesel and hanging a 4 stroke outboard on my 1967 Cheoy Lee 31 ketch.

First off; I am planning a trip down the mississippi/ Tenn-Tom, to the Gulf in early spring. I need a dependable motor for about 800 miles of rivers. I don't really have the money for a new diesel. $8000.00 would be needed. For that sum, I could buy a 4 stroke outboard with remote controlls, mount and tank, and still have $5000.00 left for the other items I need for the trip. I also could use the outboard motor braket to mount my windvane while at sea. Also, the motor bracket would make an easy mount for an emergency rudder.

Concerns: The diesel weighs more than 550 pounds. Will removing that much weight affect stability and sailing qualities?

Will the outboard work in rough seas. if needed. (I plan to hoist it aboard and store it in the old engine compartment when at sea.)

Will the outboard burn a lot more fuel than the diesel?

[s/v Faith]

We just had a long discussion on this here;

   
Engine Pull Thoughts

I think you will find much meat on that bone.

[s/v Faith]

As an interesting aside, I encountered a Cheoy Lee, it was a 33 ketch on a recent delivery.

They had spun a bearing on the inboard and mounted a (IIRC) 25hp outboard... it worked, but they had trouble with the arrangement.

Read a little more about it here.

[Sheppy]

From someone who has one.   :)   My 26 foot yacht originally had a diesel inboard.  By the time I got her she's had an outboard mounted in a well, then changed and mounted on a bracket.

A couple of points mentioned on the other thread that are relevant.

1 - Mounting an outboard on the transom (especially a sloping transom like my Quarter Tonner) puts the thing a long way back.  Someone on the other thread made the point that raising and lowering would be difficult.  Not so.  A pulley on the taff rail.  A rope from the front handle of the outboard, up through the pulley and down to the sheet winch.  My 56kg outboard (somewhere in excess of 120lbs) raises and lowers very easily.

2 -

If you do this, you really are best served in thinking of your boat as engineless.  You really have to work with wind and tide a lot more than with the inboard mindset of just powering through everything.

Actually, my outboard is a 15 year old 9.9hp Electric start Yamaha 4-stroke with forward controls and the Ultra Long Shaft saildrive leg.  That gives me 3:1 gearing instead of the 2:1 on most ourboards, and a 12" x 9.5" 4 bladed prop.  Despite my fears, even in our seas (frequently 8 to 10 foot waves, breaking, 25 feet apart) the prop doesn't lift out of the water.  Most boats won't have a transom setup as bad as mine.

Cruise speed at about 1/4 throttle is 4.5 knots on half to one litre (about a pint to a quart) an hour.  
Cruise speed at 3/4 throttle is about 6 knots on about one to one and a half litres an hour.

I should also add that our tidal ranges are from 10 feet to 20 feet plus, and the flow is usually 2 to 4 knots.  This outboard setup has no problem holding 4 knots over the ground into a 3 knt current on half throttle.

My previous, same sized yacht, had a 2-stroke 8hp Tohatsu that used 2 or 3 times the amount of fuel.  It had the long shaft (not ultra long and not a sail drive) and a fine pitch prop.  It was faster to cruise, but not good pushing into a big sea.

If you decide to go outboard, and If you can afford it - Go 4 stroke Yamaha with the ULS Saildrive and the big 4 blader.  Nice and quiet.  Dead set reliable and the power feels almost like a diesel.  Oh, and the engine will stop you quickly and easily in reverse approaching a marina berth.  Not like a normal outboard prop in reverse.  lol

Hope this helps.