Informal Science
by John Bell

Boat designer Jim Michalak spends a lot of time working out powerboat performance in detailed measurements of speed vs. weight and horsepower and other esoteric stuff. Geek that I am, I find all this endlessly fascinating, but I never have the patience do formal experiments to add my own findings to the data set. Instead, I seem to work from informal experiments that just seem to happen when I’m out goofing off in the boat. In the interest of science, here’s the story of how I got my latest data point.

I was motoring down the lake on a Wednesday evening, in my AF4, when I noticed a PWC with two riders towing another PWC and rider. All were trying frantically to wave me down. (The lake is a very lonely place on a Wednesday evening at sundown.) I went over to them, and they told me their tale of misadventure and woe. The PWCs were the property of one of the rider’s boss. They had departed his dock, about 12 miles from their current location after each putting $10 worth of gas in their borrowed PWCs, heading for a destination they did not know was nearly 20 miles from where they began. They also had no idea that their boats only get about two to four miles per gallon.

Well, they never found their destination. So they rode around checking out some of the hundred coves in the area looking for it. Then one of the skis ran out of gas. Using an old fish stringer as a painter they towed the dead one to a marina nearby with the remaining ski, only to find that the fuel dock was closed. Secure in the knowledge this was not the only marina on the lake (because they had ridden past several on the way there), they decided to leave that place of safety and try to tow the dead jetski to the next marina “just around the bend” or so they thought. Problem was, the nearest alternate marina was about 3.5 miles in the opposite the direction they headed. The marina they thought was “just around the bend” was at least 5 miles from where they were.

If you think jetskis get appalling fuel economy at speed, let me tell you they do even worse at sub-planing speeds towing another boat. By now our crew noticed there was a fuel gauge on the remaining jetski, and it was dangerously low. They were now a mile and a half from the marina they just departed, it was getting dark, and they were on the verge of having two dead jetskis. That’s when they saw me.

When I got there, they told me their situation. I don’t think they expected my response, which was mostly laughter as I expressed my opinion on how dumb they were for not paying attention to the gas gauge and worst of all, leaving a safe harbor with a disabled vessel in hopes of finding more fuel somewhere else. I guess it takes a few years and a number of bad experiences to learn that you should never intentionally make a bad situation worse. But they were all about 18 or 19 years old and therefore completely clueless. The only redeeming feature of this empty-headed crew was that one of them was female, good-looking, and in a tiny bathing suit.

They asked me if I could give them some of my gas to get back home. My AF4 only has a 3 gallon gas tank which ordinarily is more fuel than I can burn in a day of boating. She’ll run 50 miles or more on 3 gallons, depending on how fast I want to go. But it’s still not that much gas. Again, they were surprised at my laughter. I explained I only had about two and a half gallons on board to split between them. Figuring in the best case their boats could go 4-5 miles on a gallon, and they had to go something like 13 miles to get home, giving them even all of my gas would do them no good at all. (All the fuel docks on the lake are closed by now.) Not to mention that it would put me in unnecessary jeopardy.

I wasn’t going to tow them the13 miles back to their home dock. Instead, I offered to tow the dead jetski to a nearby Army Corps boat ramp where they could get on the phone and find out who their real friends were! We rigged a line, and I took the dead PWC in tow. As soon as we started moving, their other boat ran out of gas too.

So where’s the science, you ask? Okay, here comes the performance data point: I now had two PWCs in tow, about 1200 lbs total. I also had three teenage passengers aboard in the form of two skinny boys and a lovely, scantily clad young lady. Including myself and my gear, I figure a total payload of around 700 lbs. My boat and motor weigh around 500-550 lbs. All told we had 1250 lbs in the boat and were towing about that much. With just me aboard, my boat will run 22 mph wide open. In this configuration, we saw only 6 mph maximum, no matter what throttle setting. The motor wouldn’t rev either. My 9” pitch prop was just too tall for this load.

(While I did have my digital camera with me, I’m afraid that I neglected to take any photos of this scene, particularly of the more attractive member of my new crew. Hopefully the lack of pictorial documentation won’t render this important data point moot in the eyes of my peers in the small powerboat scientific community.) Editor's note: we have included a picture of John with his daughter as well as a couple of shots of his AF4 to make the article more interesting

On the way back we laughed a bit about their predicament. I observed how fortunate they were to have a woman along, as that would give them the opportunity to extend their suffering many, many days beyond this evening. Judging from the downcast faces, they had already realized this. She shot me a look that said “You don’t know the half of it, buster…”

The 19th century author Ambrose Bierce once defined happiness as “the agreeable sensation arising from contemplating the misery of others.” At this moment, I truly understood what he meant.

We eventually got hold of the PWCs’ owner on my cell phone and arranged to have him come and deal with his foolish employee and friends. When I left them, they still had lots of problems to deal with. How to get the two dead jetskis back to their dock, after dark and without a trailer? How to appease the P-O’ed girlfriend, and what exactly to say to the boss? At least they were safe, and maybe, just maybe, they learned something. And I got my data point! Ain’t science fun?!