Update! Today I took off work with a couple of spearfishing buds, and I got to try the Permatrim for the first time. It was a short trip, just under 4 miles from the ramp, through the harbor, and out the inlet where we occasionally spear fish at a very productive jetty. As far as stability, I did not run it long enough to try all the trim positions, but from what I saw it did hold more level and did less porpoising. A smoother ride indeed.
The thing that did stand out however, was the fuel consumption. That short jaunt with just one other diver and myself used to burn 1.1 gallons based on the fuel-flow totalizer. Today I only burned 0.8 for the same destination. And that's not all. There was a an additional diver with us today, with all his gear. I realize it could have been wind conditions or tides, but the time in particular that I recall, the tide was within 15 minutes of todays high-tide. We also left the dock at the same time as before. Even the total fuel consumption after making the return trip and relocating a couple of times, was the lowest I've ever experienced. I'm convinced this hydrofoil is definitely impacting fuel economy.
The jury is still out, but I like what I see so far. I would like to compare it to some wrecks offshore that I also recall the consumption for. All I really need to do is pick a straight course and make note of the gps miles travelled for any one gallon consumed. I've done this several times and keep getting a figure of approx. 5.5 mpg.
If anyone installs one of these, be sure to use a very low torque setting for the ten 1/4-20 bolts they supply. They claim that grade of SS bolt is good to 10 Lb-Ft, but after one snapped and the others felt "stressed" I looked up ratings for bolts much harder than the soft stainless I used. Some of the harder ones were not even rated for that much. So I chose a more conservative setting for the temporary button-head bolts. The bolts supplied were a very low-profile "truss-head" bolt. Does anyone really think that a round head of these bolts will actually cause drag?. I would prefer to just keep the temporary button-heads I substituted, even after the truss-head replacements come in. Is the head of these bolts really that critical?
