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Old 11-05-2013, 04:16 AM   #1
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trailing sea

My 2006 mainship pilot is hard to handle in a trailing sea almost dangerous if the seas get to bad. Has anybidy considered adding a larger rudder.
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Old 11-05-2013, 08:47 AM   #2
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My solution would be to trim the bow all the way up and run at the same speed as the wave train. ANY boat CAN be spooky in a following sea. It just depends on how steep and how big. If you run faster than the wave train then you have to keep your eyes open as the bow can jam into the back of the next wave potentially causing a "broach". I have done it...once. And while it wasn't a real broach, the boat basically stopped in it's tracks...and I could hear everything done below shifting/crashing. Bottom line is you just have to pay attention to what the boat is doing in relation to the waves. It is not relaxing and can be stressful.
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Old 11-05-2013, 09:13 AM   #3
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My solution would be to trim the bow all the way up and run at the same speed as the wave train. ANY boat CAN be spooky in a following sea. It just depends on how steep and how big. If you run faster than the wave train then you have to keep your eyes open as the bow can jam into the back of the next wave potentially causing a "broach". I have done it...once. And while it wasn't a real broach, the boat basically stopped in it's tracks...and I could hear everything done below shifting/crashing. Bottom line is you just have to pay attention to what the boat is doing in relation to the waves. It is not relaxing and can be stressful.

Good advice. Get the bow up for better tracking. If you are going to be overtaken by a wave take off headway. You don't want to add to the speed of the overtaking wave. Take your time and adjust to the seas. Deep V planing hulls love a following sea. Square transomed semi displacement hulls don't.
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Old 11-05-2013, 09:56 AM   #4
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Anybody ever use one of these? Seabrake
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Old 11-05-2013, 11:17 AM   #5
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I read the test of the Seabrake, sounded impressive but not entirely unlike any other given drogue, except maybe the elimination of tangling.

If it's as aggressive as they say, I wonder if or how much it restricts the transom lift to the overtaking wave and therefore causing more waves to poop the stern?
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Old 11-05-2013, 11:50 AM   #6
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My Willard is one of the best boats for following seas but plenty of input is still needed when the seas get large.

If needed get on enough power to make your small rudder work best and anticipate what your boat and the waves are going to do next. If your'e in following seas from the port stern quarter turn hard (judging from experience) to stbd as your boat goes over the top of the wave because the wave will try to push your stern so far to stbd your boat may wind up parallel to the wave (broached). Then your'e lined up really good to capsize especially if the seas are large and breaking. With experience you can tell exactly when your boat will start a profound movement to line up w the waves. Just BEFORE that happens give her hard stbd rudder and if you feel the need for more control increase power at that same moment. To keep up momentum more power is also needed to overcome the extra drag of the deployed rudder. If the extra power produces too much speed a drogue could be helpful.

You'll have trouble w following seas if your rudder is too small (many or most boats) or if it does not deflect far enough. Ideally your steering will be no more than 3.5 to 4 turns lock to lock (I think 2.5 to 3 is ideal) and work with enough ease so you can work your rudder through about 55 degrees going over each wave for long periods of time or however long you may find yourself dealing w the following seas.

Most powerboats do badly in following seas so don't be too disappointed (or surprised) if your boat's performance isn't supreme.

On the bright side most boats in most seas will seem like they are about to founder long long before it's actually about to happen. Billions of helmsmen and skippers have been scared to death only to soon be easing into calm waters or safe harbor.

Murray no I've never used a drogue. Going too fast usually isn't a problem for Willy and I.
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Old 11-05-2013, 01:53 PM   #7
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I understand and thanks for the operating advice. I have been on the water commercially and for pleasure all my life so this is not new to me. The original question was has anybody tried a bigger rudder or maybe power steering
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Old 11-05-2013, 02:01 PM   #8
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Nope. I had the exact same boat as you and while it required extra attention and a bit of work, I never thought it was so bad that I needed to modify the boat.
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Old 11-05-2013, 03:22 PM   #9
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The original question was has anybody tried a bigger rudder or maybe power steering
I didn't but in retrospect I think it's (bigger rudder) a good idea. The boat never did respond to the rudder like I thought it should.
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Old 11-05-2013, 06:20 PM   #10
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I think there was a post a while ago on articulating rudders. I don't know anything about them. I try to null out following/quartering seas by adjusting speed. Definitely get your trim tabs up.
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Old 11-05-2013, 07:28 PM   #11
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Since propeller wash greatly increases rudder effectiveness, operating only one of twin engines in a following sea seems unwise.
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Old 11-05-2013, 07:36 PM   #12
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Since propeller wash greatly increases rudder effectiveness, operating only one of twin engines in a following sea seems unwise.
I think you might have your threads crossed up. OP has a single engine.
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Old 11-05-2013, 07:48 PM   #13
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I think you might have your threads crossed up. OP has a single engine.
John, he could still momentarily goose the throttle to help the boat start it's turn.
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Old 11-05-2013, 08:01 PM   #14
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Well i maybe the first to try it on a pilot. I had a friend do one on his 34 trawler and he said it was a huge difference he only added 4 inches and it was designed to bolt on to existing rudder.
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Old 11-05-2013, 08:47 PM   #15
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Too big a rudder and your steering becomes "busy." When I encounter a following sea I just go off course a few degrees, and take the swells at an angle. You'd be surprised how little it takes to alleviate the situation.
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Old 11-05-2013, 08:54 PM   #16
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Too big a rudder and your steering becomes "busy." When I encounter a following sea I just go off course a few degrees, and take the swells at an angle.
Like tacking downwind in a sailboat to avoid getting too square to the wind?
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Old 11-05-2013, 09:04 PM   #17
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Well i maybe the first to try it on a pilot. I had a friend do one on his 34 trawler and he said it was a huge difference he only added 4 inches and it was designed to bolt on to existing rudder.
I would certainly try to enlarge the existing rudder and / or reshape it to be more effective. I have tried many different rudder shapes on my transomed downeast type boat and found a wedge shape much more powerful than either a flat plate (which it came with) or an airfoil (2nd try) with no noticeable change in speed. The wedge type rudder I have on her now, with the same 18% balance factor as the others, has so much more turning power, I had to change the sprocket on my autopilot to keep it from "clutching out".
Get some TigerHair body filler and have at it right over your old rudder. You can always chisel it off if you don't like the result. Adding height is more effective than adding length because it increases aspect ratio which is a good thing.
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Old 11-05-2013, 09:53 PM   #18
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I think most people w articulated rudders would have been happy w their rudders if they just gave them more swing. Mine swings through a full 90 degrees and works really well. I just used a mounting hole on the rudder horn that's closer to the shaft. Excellent rudder response. No need for more rudder authority at all however in really nasty stuff I have used full deflection. Although if I had a flat bottomed wide stern boat more typical of trawlers I'd want a bigger rudder, faster steering (2.5 t L to L), 90 degree deflection and power assist. Top speed may suffer a tad from the big rudder though.

An articulated rudder is probably a tad better in the harbor but most of the time running the lower drag of a larger flat rudder should be better.

That said something to consider is how few of our members have foundered or capsized from directional control loss in rough going?
Yup .... could be time and money wasted.

Another thing to consider is your expectations of what your boat should be doing. Staying on course is not a requirement. It's just not necessary. Nor is it necessary to keep your wings level while flying. Bobbing around some as you go is actually better. Swinging a bit this way and that is OK too. Actually a reasonable amount of bobbing and swinging minimizes control surface deflections, the drag that it creates and pilot or helmsman fatigue. So it's not necessary to go perfectly straight. One needs to avoid those "almost lost it" moments and/or actually loosing it and going out of control.
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Old 11-05-2013, 10:04 PM   #19
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Can't rely on my autopilot with significant waves coming from behind. I have to rely on my "seat of the pants" to anticipate waves so rudder adjustments are one step ahead. It was easier with a tiller (rather than a wheel) to anticipate/counter-act the waves.
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Old 11-05-2013, 10:21 PM   #20
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A boat that will perform at displacement and planing speeds necessarily has a compromised rudder. Increasing the size could affect steering effort at planing speeds while enhancing displacement speeds.

Moonstruck is designed to operate at planing speeds, and her rudders reflect that. She has a 16 degree V all the way to the transom, so performs well in a following sea.

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