Trim Tabs...The skinny?

[BearLakeMack]

[font "Comic Sans MS"][size 3]I just added a 15 hp kicker motor to my boat and I'm a little worried about the list to the starboard side (the side the kicker is mounted) the kicker could cause. Any one have any experience with either water pressure or hydraulic trim tabs to correct listing created by kicker motors or prop torque? What's your thoughts? As always, thanks for any info...[/size][/font]
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[DennisW]

[size 2]I've seen trim tabs on small boats like ours, though typically the boats had every option imaginable. Mostly you see them on big cruisers. If your boat is listing on one side, first try to rearrange some of the weight. Most kickers are best placed on the port side. Move your batteries around, if that's an option. Even moving coolers, tackle, etc can make a difference. I've even known guys to fill livewells with water to correct a list.[/size]

[size 2]I've seen those "automatic" trim tabs advertised, but have no idea how they work. I know big cruisers all come standard with hydraulic trim tabs.[/size]

[size 2]Prop torque doesn't cause a list, but rather causes the boat to pull to one side. This is usually correctable with the directional fin on your motor. [size 2]If it sits level at rest and only lists under power, it can be a deformity in the transom.[/size][/size]

[DennisW]

[size 2]Good point, Lund man. Some transducers are really big. In fact, on my old 350A I had the dual-freq transducer and that sucker is the size of a big bertha driver head. It even kicked up a rooster tail at WOT.[/size]

[size 2]Another factor can be the motor height on the transom. You want as little of the motor's lower unit in the water to reduce drag--without cavitation or the prop blowing out. The 3rd hole up is the sweet spot on many motors. You'll also pick up top end.[/size]

[size 2]Oh, and don't forget to stow your electric motor. That makes a HUGE difference! [][/size]

[BearLakeMack]

[font "Comic Sans MS"][size 3]Well I took the boat out last night and ran it through the paces. It had a new Turbo 17 pitch stainless prop on the Johnson 115 HP Ocean Pro and the 15 HP kicker mounted on the port side. [/size][/font]

[font "Comic Sans MS"][size 3]What I had anticipated about the kicker was indeed reality. The kicker motor was weighting the boat to one side, causing it to set uneven in the water. If I stood on the opposite side it evened right out.[/size][/font]

[font "Comic Sans MS"][size 3]I wanted to see how the new stainless prop was going to perform. The reason I put a new prop on the boat is that it came from sea level and with the aluminum 19 pitch prop it's operating RPM was 4500. 100 RPM below the recommended operating range of 4600 to 5500 RPM for the motor. After some lengthy discussions with Lee at Lee's Marina in Hyrum, we decided on the 3 blade, 17 pitch Turbo stainless. We calculated that by going to stainless we'd gain 200-400 RPM and by dropping the pitch we'd gain about 400 additional RPM. This should put the motor apporximately in an operating range of 5200- 5300. Perfect.[/size][/font]

[font "Comic Sans MS"][size 3]I took off out of from Hyrum's boat ramp and eased it to full throttle. Immediately you could feel the boat pulling to the port after it was fully trimmed out. What was good was that the operating RPM at full throttle was a nice 5400 RPM. We had judged right on. After running around and getting the motor warmed up I tried the hole shot. It was had pretty good power right out of the hole and nice level acceleration if you trimmed it down at the started and adjusted the trim up as the boat came up to speed. I couldn't ask for any more. The pull problem needed to be addressed.[/size][/font]

[font "Comic Sans MS"][size 3]I took it back to the shop and talked with Lee on what we should do. Here's what we came up with. I had two 24 deep cell batteries and one Cranking battery. One of the deep cells was on it's way out so I decided to upgrade the 24's for the large and heavier 29's. Also the placement of all the batteries will change to accomodate offsetting the kicker motor's weight. That problem is solved realitively easy. Put the two 29's on the starboard side of the boat.[/size][/font]

[font "Comic Sans MS"][size 3]The prop torque, resulting in the pull of the boat was a little more involved. The tab on the outboard was already maxxed out was would adjust no further. We checked the depth of the motor compared to the bottom of the boat and decided to raise the motor 1 1/4" inches. With having to trim the motor so high and and changing the angle of thrust plus significantly more torque from the added RPM's was causing the pulling problem. By raising the engine, this will change the amount of angle to fully trim out the motor resulting in, hopefully more thrust and less rotational torque resulting in less pull. We will see tomorrow night after work. Hopefully no trim tabs yet...[/size][/font]
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[IceFishingGod]

BLM,

Since I'm at work I took the liberty of doing some research for you. Here is the link to Bennetts web site. [url "http://www.bennetttrimtabs.com/"]http://www.bennetttrimtabs.com/[/url]. Pay particular attention to the "What Trim Tabs Do" section. It might answer your questions better than I can. They have a new M80 series tab that would be perfect for your boat. Price $588.00 with the rocker switch (must have). By the way I make $28.50 an hour, the goverment will be billing you.

IFG

[BearLakeMack]

[font "Comic Sans MS"][size 3]Pretty interesting stuff. Definitely worth looking into if the problem persists. We'll see after tomorrow. $28.50 an hour? A bargain at any price... Thanks![/size][/font]
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[IceFishingGod]

How did the test go? I have two engineers on standby if all did not go as planned. Hope everything worked out for you.

IFG

[BearLakeMack]

[font "Comic Sans MS"][size 3]I didn't get it out of the shop til 8:30pm. I'm going out this morning and will let you know. I hope things go as expected! HA![/size][/font]
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