Boating at high altitude

[m4boots]

I was wondering if anyone has had any issues with running their Tug at higher elevations. We are at 4500' here and with other boats we have had to change out the prop to a different pitch. Electronically controlled engines seem to adapt somewhat to the lack of oxygen. Will I have to do the same with this larger prop and motor?

 

[RProffer]

The Operation Manual for my engine (3YM30) requires the engine be propped so that a fully loaded boat will reach a certain RPM at WOT. In the case of my boat, that RPM is 3600. The Service Manual also has settings/adjustments for no-load idle and no-load WOT. I think if you checked your Operations and Service Manuals and see what it says, and make the appropriate adjustments, then you should be okay.

I am not a diesel mechanic. If all else fails, consult your local Yanmar mechanic.

On a gasoline engine, you would adjust the fuel/air mixture for the high altitude. With a carburetor, you would adjust the jets. With fuel injection, the computer would make the adjustments. If have not seen a fuel/air adjustment listed in the manuals for my engine. The no-load idle and no-load WOT settings on the diesel are probably the equivalent for the adjustment on a gas engine.

 

[Spirit of Gratitude]

We run our R-29 at 6500ft in the summer and at sea level in the winter. The R-29 has a turbo charger which allows it to run the same in both locations.
I am not sure if your R-25 is turbo charged, but if it is then you should have no problem. If not then you would want to find a real good prop person and have a new one build for the higher altitudes. It would truly need to be someone that really knows what they are doing. Someone that insists on running all the numbers first. It may take a few tries to get it dialed in.
I am not sure how you can improve air intake on the Yanmar if that is needed other then adding a turbo. This is not my field of expertise.

From what I can tell, your engine is turbo charged.

Stuart

 

[m4boots]

Thanks Stuart, the 4BY2-150 is in fact turbocharged.

 

[Spirit of Gratitude]

Very good, That is what I thought. Thanks for confirming that.
What you will find is that your percent of power on your gauge will be higher at lower RPM's. As you increase RPM's it will all balance out.
Your boat should preform just fine. I had to go through all the prop changing with my old 26' Bayliner, even know it was EFI. I too was worried when we first brought our boat back to Colorado, but all that worry was put to rest soon after I got her in the lake.

Where will you be running you boat?

 

[m4boots]

Stuart, thanks again for alleviating the prop worries. Everyone at our dock has gone through this with a variety of gas engines, problems from not being able to reach plane on the larger boats, to loss of power and fuel efficiency. We went through the same with our C-dory.

We currently keep our boat in a slip on Lake Minnewanka, BNP, correction, we'll have it there as soon as the ice is off. Had an unusually cold, snowy, and long winter. Ice is pretty rotten but will likely be around for another week, too bad because fishing opens this Saturday.

Was glad to hear that we wont have to change props as we will be hauling the boat to the coast in August for a few weeks. Will be out there for good in a couple of years, so all this with one prop will be easier. Thanks again and we have some pics of the lake and some fish in our cbrats album (C-saddle) if your interested.