Posts: 3514
Location: Elk River, Minnesota | Hiya,
Reef, you are right on with your assessment of how many under-powered rigs perform in the tiller models. In the past years we have seen a massive influx of wider boats with a hull that is more of a deep-V (aluminum hulls) and thus heavier overall. The design is definitely smoother for the passengers in rougher conditions, but the handling characteristics (in general) decline since the boat rides lower in the water.
To me, the HP ratings on these boats are well below what they could be for decent performance. My hull (Alumacraft navigator 165CS) fits this category as well. So...what you mention is for the most part "spot-on" in that many tiller models have a hard time getting up on plane due to (best words I can come up with) stern-squat. All the weight is back there (battery, operator, 4 stroke motor, etc). What the fin does for these situations is create a larger surface on the anti-ventilation plate which then helps to push the stern up when trimmed down for hole shot. One thing must be kept in mind with these is that in order for them to consistently work, they must be in contact with the water....and many boats are set up to be this way for handling purposes, but may not be the most efficient set-up. When the boat is trimmed down, the front edge of the fin is directed toward the surface of the water, so more surface area forces the rear of the boat up.
If you think back about 10 years or so, many tiller model aluminum boats had very small v-shaped hulls to even flat across the back (like the Lund S-series of many years past). Those boats would pop up on plane easily, but if you turned, it felt like the stern was sliding sideways.
I suppose I should say this....before doing anything, check the placement of the trim-pin. Every boat has one, and most, if not all Trim and tilt models have them in the lowest (or most negative) trim hole. If your pin is NOT in that lowest position, move that first, and test. The idea being to get more negative trim where the lower unit looks like it "tucks under" the transom, which will help the stern in hole-shot.
Moving the motor up off the transom (I feel) is always a worthwhile thing to try...you have less lower unit in the water, which equates to higher RPM's. This usually works best with steel props, which flex less and usually have a better ability to get a bite on the water. BUT...every boat would perform better if the motor is mounted higher. It will in some cases allow the bow to rise less, and it may help to get more boat out of the water at planing speeds as well. The only way to tell is to try it...so it never hurts, and in many cases, you might get a good surprise too. What is interesting is that many of the larger deep-V walleye boats can have the anti-ventilation plate mounted around 2 inches ABOVE the lowest part of the transom. Reason being is as soon as the boat moves forward, water rises back up to fill the hole the boat made. There is a limitation to this, but in most cases, being in the 3rd hole up will still do well...even with an aluminum prop.
Steve |
