trim tab help

J

Jake B

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C Dory Year
1989
C Dory Model
22 Cruiser
Vessel Name
PLUS 3
so we got the trim tabs installed on the boat this weekend. went with lenco 9x12. so we ran over and around the san Juan area this weekend fishing and hanging out playing with tabs ect. so my question is this on the way back the weather kicked up and got a bit snotty especially getting off hein bank.

my boats set up is dual batteries kicker and me all starboard side, I tent to trim main to keep nose where I want it at but to get ride of the list on the starboard side i have to engage the trim tab just shy of half way.

So on the way in we were dealing with 1/4ing waves and at times following seas. I have read that in especially following seas to bring tabs up. but with getting hit by sideways waves and whatnot I kept the tab down to level boat. so my question is what is worse unlevel boat in semi confused water.

I didn't experience any problems in doing this, but this wont be the last time this happens.
 
I would rather deal with a boat off level than with the increased likelihood of broaching due to the bow being pushed down by the tabs.
 
I agree running in heavy weather or beam on I like tabs up so I can play the throttle in waves without a bunch of tab induced steering. Nothing really big so far but breaking 5-6 footers in Georgia strait chop is crappy weather on any point It's possible you can move some things to trim the boat more level. (These are dory's remember and let 'em roll! They aren't gonna roll over like others out there )Ie keep water tanks full move loose things over and look thru your lockers is your tool kit and spare anchor etc also all on staboard? Try for a pretty level static trim. I have Kerri On really quite level by stowing heavy stuff opposite water tanks. I have it easier though as no kicker and batteries are on the floor under the splashwell. George good luck
 
Jake, In the following seas, you are OK with some bow up attitude. It's a flat bottom, so it will surf some, and that's OK. Less likely to get the bow into a wave and get caught with some unwanted bow steering.

The Strait's can be fun but the sea state can change pretty rapidly. Watch the current direction, depth changes and wind direction. It can be like a washing machine right where you are and 1/4 to 1/2 mile port or starbd it'll be half the wave action. Last weekend it was pretty nice, enjoy it when you can.

Nice to see another active boat here in Sequim.

Harvey
SleepyC:moon
 
thanks for the replys, at the time i felt more comfortable having the tabs down, and for the most part was able to 1/4 most of them even though it added more time. once off the bank we were fine 17 mph little throttle here and there run in. of course it was on tide change that we ran in but the wind kicked up so did the caps and we didn't want to waite if it got worse.
I have everything else on the port side even keep the down rigger balls on the port side. I should fill the water tank and i'm sure that would be about all I need to do, my buddy that was with me I have 15 pounds or so on him. first time going just the two of us. usually been three and that makes it fine for running,

I need to start watching currents ect. we checked NOAA for wind and just checked tide tables(although more for fishing). I am digging the boat and never felt uncomfortable. just first time having tabs on a boat so really new to it.
thanks again for the pointers.

sorry about the spelling errors in first post did quick spell check but never re-read until now....
 
I don't believe there is an absolute answer when it comes to trimming a boat in varying seas. There are rules of thumb, i.e., trim tabs up and main trimmed to provide bow up ride in following seas, but it's really by feel. If you feel the boat bow steering, trim the bow up. If you're quatering waves, and making good way, you may not have to worry about following seas having an effect on a lowered trim tab. You just gotta feel what the boat is doing in any given sea condition.
 
So, let me get this straight. Trim tabs down, following seas could push the stern down deeper if you are moving slower than the following sea? At least that seems what it would do and that it would not necessarily be a good thing to be doing if you are going slower than the following sea. If you are in sync with the following sea, then it would seem that you could set the trim tabs pretty close to if you were in fairly flat water?

As a mountain lake boater, I'm not sure I fully understand the "bow steering" issue. I've probably dealt with it, but haven't been able to put a name to it. What is the action of "bow steering?" I would think that you are naming a condition where seas action on the bow is excessive relative to the steering action from the stern mounted motor or motors? That may be due to the bow being trimmed too far down?
 
Harry, bow steering is when you're traveling at a relatively high speed and the bow is deep in the water and it gets hit from the side by some heavy water. The boat turns quickly and if you have not experienced it before, you feel as if the boat could broach. You cannot turn quickly enough to counteract it.

Not a pleasant feeling.

Charlie
 
Just what I thought. I haven't hit that kind of bad wave action yet, but I have experienced mild "bow steering" on lake powell in some of the bigger winds stirred water.

Thanks.
 
potter water":35nsji4b said:
Trim tabs down, following seas could push the stern down deeper if you are moving slower than the following sea?
Click to expand...
Actually, it's the opposite. For following seas to be an issue, there is usually a significant swell associated with it. So imagine the swell (wave) catching up to you, rolling underneath, and then lifting the stern by acting on the trim tabs. By lifting the stern it forces the bow down and if you're on the front of the wave, you'll surf down and be driven into the trough. With the bow down like that you face the risk of severe bow steering and broaching if the swell is large enough.
 
Bow steering happens when the boat surfs down the front of the following sea, and if at an angle and the side of the boat facing the wave in front, catches, or really digs into that wave, it is pushed away because the side presented to the wave is more flat. Thus it is pushed away, and the boat yields in the off wave direction. The bow is going down and sideways and the stern is coming up fast, lifting and turning. It is a veerry disconcerting feeling, and could have bad results. It could, but I don't believe we have had any C-Dorys that have flipped in that situation but for a few seconds, you really do wonder. (Yup, BTDT and I am really thankful that the 22C-Dory could handle more than I could. After nearly 3 hours of surfing port quartering following waves it was a real relief to turn port behind the point and head up the passage east towards Princes Louisa.) That was an introduction to my C-Dory that I will always treasure. A true expression of sea keeping in the finest.

Harvey
SleepyC :moon
 
Harvey makes good points. You do not want to surf a powerboat! Sailboats it's a lot of fun. You have a rudder. Outboards no. These boats can take more than we want to. Downwind in big waves just keep square on and adjust speed so you aren't faster than the waves passing. The boat will bob up and down slowing on the climb speeding up on the face. You'll know if you're going too fast as on the face you're speed will come up and you'll overtake the last wave. I had a buddy out a couple years ago in my new 19 showing a harbor tour. We went outside Newcastle Island into a very fresh nw breeze of some 25 knots and turned downwind and rode 4 footers very comfortably.... For me. It dawned on me he's got zero miles in boats and might be concerned. So I asked him if he was ok with it. He said ssssure if you aaare. So I told him this is what dorys are made for and notto worry. In a while he started pointing out the big ones coming up. Fun
 
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