Twin Engine Installation

[Tom Schmidt]

I have decided to build the Yukon, plans from Glen-L. I would like to install twin diesel engines but cannot find any information on how to do it. The Yukon is designed for a single engine with a large deadwood skeg, but twin engines are optional according to the specs. Would you still use the large deadwood with twins, or could you cut it down some or even eliminate it altogether? If you eliminate it would you increase the size of the inner keel plank to compensate for loss of stiffness?

Is it better to put the engines as close together as possible, or what would be the best spacing?
The plans recommend a single engine of around 100 continuous shp. What would I need for twin engine hp per engine? Is there a rule of thumb to convert HP to Continuous SHP for planing perposes?

I've got some books on inboard motor installations, but they don't tell me these sort of details. I have also e-mailed Glen-L several times, and all they tell me is that they don't provide that information. I'm really getting tired of that response from Glen-L. I sure wouldn't recommend them for plans or anything else if you might need help with something.

Any help will be greatly appreciated.
Thanks
Tom

[Ken Liden]

The horsepower requirement remains the same to obtain the same speed. I have some experience with the Klondike which is a bigger sister if I recall correctly. Going with twins in that small of an application seems like a lot of expense for little or no gain. The spacing in your case will be limited by your bottom shape and the height of the deck plates, and the height of the engines. I think the wider spacing the better both for boat handleing and engine maintainence. I would not remove or minimize the deadwood even tho these are semi-displacement boats. The continous horsepower rating is determined by the manufacturer and it is as the name implies that RPM and horsepower at which the engine can be operated continously. On gas engines it is usually around 75 to 80% of the full throttle setting. Many diesels use about the same numbers however there are a few that list the maximum and continous as being the same.

I have always found Glen L folks to be very helpful. I think that boat was designed by Ken Hankinson and I am sure I have run across his web site. He would be the best person to ask.

[Tom Schmidt]

Ken,
Thanks for the info. Do you know how I can get in touch with the designer of this boat? He might be able to give me some specific info.
thanks again
Tom

[Adam C]

there is no conversion from continuous HP to HP. It's the same. This is the engine rating given by the manufacturer. You need to buy an engine that can put out 100 continuous HP. This would aobviously by an easy RPM for the engine to run at, and listed on the manufacturer's spec as the continuous rating of the engine. This is different from the intermittent rating, which gives you HP and RPM figures for short bursts.

I.E. We use a Yanmar 6LY STE on our 35 footer. It is a 350 HP engine. The continuous rating is 2900 RPM which is about 265 Horsepower. The Max RPM is 3400, which equals about 350 HP. The manual says not to run at 3400 RPM for more than 30 minutes.

In your case you probably need a 150HP engine to get a continuous 100 HP. Check with your engine dealer.

Also twins will be more money, more maintenance, higher center of gravity because they are place higher and further outboard, more difficult to access, and provide more vulnerable shafts and props.

[brad9798]

Boat was designed and engineered for small, efficient, single screw ... including handling, etc. I wouldn't mess with that.

Planing? I wouldn't worry about planing either- not with that hull.

Perhaps the study plans would divulge more info. on twins, though???

Brad

[Tom Schmidt]

I think you guys are right. I think I will stick with the single engine. I was just concerned about redundancy for long trips,(that must be the avaitor in me showing through) but I think I can work around that with a generator and some kind of get home setup, without the added expense of the second engine. I don't like the idea of having to raise the cabin sole to accomidate the twins either.
Thanks,
Tom

[BILL CANNON]

YOU CAN ACCESS KEN HANKINSON'S WEBSITE AT BOATDESIGN.COM AS HE DID A GREAT DEAL OF THE DESIGN WORK FOR GLEN L, HE MIGHT BE ABLE TO HELP WITH ANY PROBLEMS YOU ENCOUNTER UDRING YOUR BUILD. GOOD LUCK.