"Squirrely" Boat Handling?

Well, I finally have a few hours on my new "baby" - a 2002 Crestliner Angler 1600 S/C with a 50 horse Merc EFI 4 stroke. So far we love it! My problem/question is that when I got the chance to open it up, I noticed two things:<br /><br />1) On flat water (in a slough with only a slight cross-wind) I could feel the tail get kind of "squirrely" (fishtailing) and this was not even W.O.T. and trim was all the way down;<br /><br />2) I can easily get an over-rev alarm at top end. The tach will shoot up past 6200!! <br /><br />The dealer set it up with an 11 pitch prop. Is this "prop-wash" or cavitation causing this?

Re: "Squirrely" Boat Handling?

The fishtails sound like a trim issue. Get the trim right first. You might be overrpropped but you need the boat trimmed properly to know for sure. It can be hard to trim an aluminum because of lack of overall weight and I wonder if your boat is well suited for the weight of your 4 stroke.

Re: "Squirrely" Boat Handling?

If your revs are shooting up with no change in speed you are probably cavitating. If you have power trim you may be trimming out too far. Or the cavitation plate may need to be a little lower.The wiggly tail may be trimmed in too far <br />putting too much boat in the water.You could have someone look at the cavitation plate while planing<br /> should be at or just below the surface of the water.It may require a little fine tuning.Motor height can be critical.Too low and your dragging too much motor.Too high and it becomes sensitive<br />Possibly causing strange handling but mostly <br />cavitation, causing blow outs (severe cavation)under hard acceleration,or in rough water or when turning.<br /> Once you are sure the motor is at the right height then you can play with the in and out trim.<br /> You may want to check to be sure the motor is placed correctly on the boat anyone can mess up. It Could be off center or even tipped sideways surely not likely but give it a look.<br /> Good luck, Spike

Re: "Squirrely" Boat Handling?

Thanks for the info. The fishtailing just kind of happens intermittently. It will be going along fine then all of the sudden "twitch" - almost like I went through a cross-current or a wind gust. Then it dissapears. I'm pretty sure the motor was trimmed all the way down, but I'll check it out. <br /><br />When the over-rev alarm sounded I know was with the motor trimmed all the way down and I was accelerating from slow speed and the alarm went off after the boat planed. But I was running "light" - just my son and myself in the boat. The other time I opened it up I had my wife & kids in and it went up to 6200 rpm's without alarming.<br /><br />I will measure the motor placement & plumb.<br /><br />What exactly is the "wiggly tail" that was mentioned?<br /><br />Would a set of "Dol-Fins" help out any? How about a higher pitched prop (13 or 14?)

Re: "Squirrely" Boat Handling?

Sounds to me like something is just plain out of whack with the rigging of the outboard. I would take it back to the dealer and get it fixed. New boat, right? Messing with fins and props will just confuse the problem.<br /><br />Kelly Cook

Re: "Squirrely" Boat Handling?

I personally think you are way under pitched on your prop. I have a 17' Lowe (MT1760) that weighs about 1200 (fully loaded the way I fish, including motor), and I run a 15 pitch cupped SST prop with a 50 HP 4-stroke Mariner. I normally fish by myself.<br /><br />On a glass water surface, I can hit 5700 - 5800 rpms when I play with the trim. I had to add a Doel Fin, because it would porpose very easily before I put it on. <br /><br />When I add another 300 to 400 lbs in the boat (such as my daughter and another fishing buddy), I can only hit 5000 to 5200 rpms. But she still planes very quickly, and will get close to 10 mpg on smooth water running at around 4500 rpms.<br /><br />Depending on your total overall boat weight, I would recommend a 14 or 13 pitch for your boat.

Re: "Squirrely" Boat Handling?

NuBoatR,<br /><br />I agree with SeaDawg, you're underpropped. You are reaching your max. rpm. far too quickly. I would think (like SeaDawg said)a 13" or 14" would be better.<br /><br /> You can get some strange feelings from the sttern when you are running too much negative trim. You are lightening the stern and forcing the bow down.