Pontoon & Deck Boat

www.pdbmagazine.com Pontoon & Deck Boat Fall 2017 46 Horsepower has been an issue from the beginning of the internal combustion engine. In fact, it started way before that. Bigger oxen, bigger and faster horses—it has been a battle for mankind from the beginning. My goal for next year is getting back into lake slalom skiing which includes deep water starts and gentle sweeping runs on glassy smooth water. More likely it will be deep water starts on a lake covered in whitecaps filled with boats pulling tubs on a busy weekend, but it's still my goal. I can do that with my current Mercury 60hp Big Foot outboard, but I'll need to upgrade my ski (or my hamstring). But another way is to increase the horsepower (or even better, both). I have been looking for a good reason to repower the SkyBoat (the boat name came from me and a Scottish song). Sure I can go buy a bigger boat, but I really like mine. Plus a new boat will cost way more than a new ski or even a new engine. So let's just rationalize the engine portion. Rationalize, did I tell you I am married to an accountant? She says she is a "recovering accountant" (which I don't think exists). Anyway, as an accountant she likes spreadsheets, balance sheets and actuarial methods to analyze the actual costs and benefits of changes I make. I use a different method: I like the idea, and it feels good, done. Mine doesn't always work, but hey, I'm not giving up on a plan just because it didn't work out exactly like I wanted. I'm no quitter! So my plan is to repower SkyBoat with a bigger Mercury outboard. (Hey Mercury, send me a super deal for the accountant to review.) My `toon is a Bentley Cruise 200 SE, two-tube boat with a maximum horsepower rating of 115. Of course if I had a factory Cruise 203 triple pontoon the limit would be a 150 horsepower. Even though my boat is now a triple with the Pontoon Wholesalers 3rd toon kit, it is still certified from the factory as a two-tube with factory specs of 115. So I did a bit of practical research. If I increase the horsepower I'll definitely increase the weight on the boat. I'll also increase the fuel burn. But hopefully the increase in speed and power will be enough to offset the fuel burn, weight and of course the cost. The Mercury 60 Big Foot has a dry weight of around 260 pounds. Both the Mercury 90 and 115 Command Thrust have a dry weight of 363 pounds. The 100 plus weight increase does cut into my useful load, but I'm usually running below the maximum load most of the time anyway. With the addition of the third pontoon I lost a bit of my useful load (weight of the 3rd toon and rails) but gained extra buoyancy for more comfort with higher loads (still not changing my certified limits). The SkyBoat has always sat a little low in the aft anyway, what's another 100 pounds? Besides the weight, I'll also increase my fuel burn. An old rule of thumb is to take the horsepower and divide by ten and that gives you an approximation of fuel burn per hour at full throttle. Most of us don't operate our pontoons at full throttle all the time so this number will seem high. With a 60 horsepower engine, 60 divided by 10 would equal about 6 gallons an hour at full throttle. So a 90 would be 9 gallons per hour and a 115 would be 15 gallons per hour. Remember, this is a rule of thumb. In my case, for the difference in weight and fuel burn, why get the 90. I need to jump to the 115. I'm okay with the higher fuel burn and the weight isn't any different. Plus, with the higher power I will not need to run the 115 at full throttle to get the same result that the 60 gets, so the fuel burn should be lower. How much of a speed increase can I get? It's really an unknown until I make the change. Estimates are three to 10 miles per hour, but I am skeptical. Since the 115 is almost double the horsepower, in my dream world I would hope for doubling the performance, but in reality that's not the case. If I can get even a 20 percent increase in speed I'd be happy. But I think more important, I should be able to get more torque "or out of the hole" power, and that would be even better. Horsepower, what do we do with it? By Sky Smith Staying In 'Toon Boating tips and observations with Sky Smith

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