Piloting Displacement vs. Planing Vessel

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ryanleestma

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Oct 15, 2022
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Greetings:

I am under contract to purchase a 75ton displacement trawler. I have three decades of experience piloting planing vessels but have never piloted a displacement vessel before.

During my sea trial my path looked like a snake, I couldn't get a handle on turning the rudder, how long it would take to respond, then had to overcorrect etc. etc.

I know there are a lot of displacement pros on here so I thought I would ask for tips. It's a 75 ton 70' vessel, cruises at 8-10 knots, maxes out at 13

Thank you,

Ryan
 
A properly configured autopilot will do a better job keeping a true course than a human in most conditions, they don't get distracted and make trawler piloting far more enjoyable.
 
When you say properly configured do you mean heading-wise or are there specific settings that should be programmed into the auto-pilot to account for the displacement vessel type?
 
I am surprised you are having problems maintaining a straight course with your 70' displacement trawler. I would expect the steering to be rock solid on a boat like that.

Maybe there is some problem with the steering. Check for play. Have someone turn the wheel back and forth 5-10 degrees and watch the rudder post.

If it is hydraulic steering a worn steering pump or maybe a leaking hydraulic cylinder could cause this. I once helped a guy deliver his project Mainship Classic 34 that had this problem. We couldn't steer it in a straight line from the upper helm, but the lower helm was fine. The problem was the upper helm pump.

David
 
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DavidM said:
I am surprised you are having problems maintaining a straight course with your 70' displacement trawler. Maybe there is some problem with the steering. I would expect the steering to be rock solid on a boat like that. David
Click to expand...

+1. If the vessel doesn't track straight there is an issue, whether rudder size or location or ???
 
If I can remember when I'm at my PC, I'll see if I can find a fairly simple diagram. From memory, there are three general adjustments. Rudder (how much rudder to apply), counter-rudder (this is a 'kick' in the opposite direction to center the boat after a turn);, and gain (amplitude, response time).

Different manufacturers use different nomenclature, so if you can provide your A/P manufacturer, I'll see if I can find the manual and take a look. Normally, people over-adjust their settings thinking it needs more response. 90% of the time, the adjustment needs to be reduced to give the boat time to respond. Too tight or too little delay (gain) causes over-correction and oscillation (serpentine).

If the boat is serpentining, I'd check counter steer setting and reduce it (somewhat counterintuitive). May also have to reduce gain (also somewhat counterintuitive). Make sure to have a pad and paper to write down original settings. If the boat is drifting off course or slow to return to a heading once you dodge something, rudder needs to be increased.

Most displacement boats run at least two A/P settings. One for normal conditions, one for more boisterous conditions that have more rudder response.

Peter

EDIT - is the problem with hand steering, AP, or both? If handsteering, try slowing-up your course corrections. Heavy boats tend to self-correct.
 
On heavier, slow boats there is a lot of directional inertia. It takes several seconds for the boat to start responding to rudder, and you need active counter rudder to stop the turn. Centering the rudder won’t do it. The boat will keep turning for a while.

Do you have a rudder indicator? I think that’s essential so you can confirm where you have the rudder.

Underway, I never need more than 1-2 deg of rudder to keep the boat on track. More if seas are fighting you.

A pilot should be able to steer better than you, but some are better than others at handling heavy boats.
 
If the surveyor did not check or note anything then send him back there again.
 
twistedtree said:
On heavier, slow boats there is a lot of directional inertia. It takes several seconds for the boat to start responding to rudder, and you need active counter rudder to stop the turn. Centering the rudder won’t do it. The boat will keep turning for a while.

Do you have a rudder indicator? I think that’s essential so you can confirm where you have the rudder.

Underway, I never need more than 1-2 deg of rudder to keep the boat on track. More if seas are fighting you.

A pilot should be able to steer better than you, but some are better than others at handling heavy boats.
Click to expand...
Twisted is on the right track with this response.
 
twistedtree said:
On heavier, slow boats there is a lot of directional inertia. It takes several seconds for the boat to start responding to rudder, and you need active counter rudder to stop the turn. Centering the rudder won’t do it. The boat will keep turning for a while.

Do you have a rudder indicator? I think that’s essential so you can confirm where you have the rudder.

Underway, I never need more than 1-2 deg of rudder to keep the boat on track. More if seas are fighting you.

A pilot should be able to steer better than you, but some are better than others at handling heavy boats.
Click to expand...


That's exactly it. Slow responses to inputs are unnatural for humans, so it takes some time to get a feel for it. In general, err on the side of turning too little, as you can always add more if you don't get enough response. If you over-do it, you just end up chasing it.



Need for counter rudder will vary based on how tightly you're turning as well. The tighter the turn, the more counter rudder you'll need on many boats. Coming from planing boats, you'll find that strange, as I've never known a boat that needed counter rudder on plane. My boat doesn't need it on plane, but at low speeds if you're turning tightly it does need some to end the turn where you want. Gentle turns typically decay fast enough that you don't need counter rudder.
 
I assumed that the OP was talking about S turns while hand steering, but maybe not.

Clarrification please?

David
 
What everyone is saying regarding turn less / counter steer etc. is what I need to hear - on my planing boats I could feel the response and never had to counter steer - with this boat I couldn’t get the feel for how much to turn and the. Counter

The advice to do 1-2 degrees is helpful - I was doing 5 waiting for it to start moving and then reverse ruddering 3 or something like that.

Patience has never been my strong suit but I overcame it with my prestige. Seems I need to overcome even more impatience ha

Any other advice please please!
 
It may just take some practice to figure it out. You will need to meet the helm, bring it out of the turn before the boat gets to the heading you actually want, because it will continue to turn after you straighten the helm. Have fun with the new boat.
 
Twisted tree is on the right track. First thing would be having a rudder angle indicator. You’ve got a large heavy hull with I’m sure a full length keel that has some profile depth. This combination should provide excellent directional stability at the cost of quick steering response. My guess is you need to just get the hang of steering this heavy vessel. In different sea conditions if you’re on the wheel you should find a rhythm where you anticipate when to swing a few degrees ahead of time. In a following or yawing sea this type of hull properly helmed should be a pleasure compared to most lighter hulls. An autopilot shouldn’t have a problem not with this hull. Got any underbody photos

Rick
 
The boat does not have a keel as it is designed for shallow depth cruising - it only drafts ~ 4 ft
 
That’s interesting 75 tons no keel draws 4’. Now I’d really like to see some photos. Round bilge or modified Vee. Is she real beamy ?

Rick
 
Next time you are underway, just find a fixed point you can see clearly and focus on maintaining a course on it, your eyes brain and hand will calibrate themselves to your boat pretty quickly. In my opinion this is much easier to get a feel for a boat rather than using a chart plotter or compass. Obviously those are going to be needed at some point but the learning curve is much quicker if you can keep your eyes outside the boat.
 
Good advice above. On a slow underpowered boat you have to pay attention to the rate of turn and be done correcting when you get to the desired course. It's tricky and not intuitive if you're accustomed to fast power boats.

I have a slow 50' 17 ton displacement boat, and it took me a while to learn how to manually steer it in a straight line. I was relying pretty much entirely on the AP for the first 2 years/10k miles with the boat, and had it well dialed in. It failed suddenly this summer and I've been manually steering since then.

I can tell you that anyone following my track for the first few days after the AP failed would have been confused or concerned. When it failed I was in northern Lake Michigan, and it was about 2 am and overcast with no visual references. I was steering giant S curves for the next few hours. Luckily I had the lake to myself. Now after a few hundred miles hand steering is becoming more automatic and fewer course wobbles.



Sent from my moto g play (2021) using Trawler Forum mobile app
 
Very interesting. How well does a vessel with no keel track? Or is it just by essence of its narrow L/B ratio?
 
I have hand steered large vessels that tracked straight without AP. Obviously wheel inputs are not instantaneous. Likewise I’ve hand steered large vessels that were a handful. I know of one case where a single engine large FD vessel needed two more rudders installed to bring it up to acceptance.

Since this is an under contract situation don’t assume all is ok. Possibly another sea trial with an experienced helmsman is in order. Also, is the rudder post at the stern or forward a few feet? Is the vessel stabilized? If so, a poorly functioning stabilizer can skew the vessel forcing never ending rudder control.

PS
Do I note a new hull design?
 
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We had a Class A diesel pusher motorhome. It took a while to get the feel on how to steer it. If you waited until it was obvious that you needed to steer right, for example, it was too late. Then you got into a cycle of back and forth scary deal. You could feel it in your butt as it was starting to sway off a straight line. Then you did a bit of counter steer and could stop it before it got started. My wife never did get the feel for it and a couple of times I thought she was going to lay it over on it’s side. I stopped letting her drive after that. It will probably become more natural to you as you get experience driving the boat. After a while it will become second nature and you won’t have to even concentrate on it.
 
I had exactly the same problem when I purchased my 48 ton 50 foot trawler. Couldn't steer a straight line to save myself! That all changed when I installed a new autopilot which displays the rudder angle.

Seems the problem was also compounded by a low level of fluid in the steering system allowing some slop in the wheel. Not something that a surveyor would always note.

The delay in turning the wheel and something actually happening to the boats direction was also part of the equation. This is just experience but the rudder angle display helped a lot.

The autopilot can steer straighter than I can to this day but at least I don't have the problems I had initially. Stick with it, get a rudder angle sensor and make sure there is no slop in the hydro.
 
Very helpful gentlemen - seems I just need to go out into Lake Michigan and practice slowly steering towards a visual marker to get the feel for it

Very helpful! Thanks!
 
Sorry but I’m confused. These links you’ve provided are a’ Bering ‘ but you’ve not told us the name, model or builder so how do these links relate to your inquiry or vessel you’ve committed to ?

Rick
 
Yeah it takes a bit of time to learn "slow boat steering"

I came from outboards, none bigger than 21 feet. You turn the wheel and the boat turns.

Not true with our 44 foot double diesel. You turn the wheel and nothing happens. So you turn some more and too much happens and you crank back...

If you were on a road the cops would suspect drunk - :)

Yeah the boat takes time to respond, as said a lot of inertia.
 
The most important thing it is to find the point of "équilibre" it change for each sea/wind/heading condition (it could be little more on starboard or portside.
It means not to be focused on the compass and/or ruder angle.

Just looking your bow on the horizon line and you will see sometime before the compass ( not easy on "small boat but for example on big ship your bow is sometime 300m far away , and you can see her movement before a magnetic compass).
After found the "point of equilibre" normally don't need big angle mainly small move of the wheel.
For example this year our first crossing (250nm) we do all by "hand steering" my autopilot oups sorry my wife do the majority off the crossing at the helm (she is better than me for that, may be you coud ask to your wife to steer :) )
First she found the point of equilibre, after that seat on the wheelchair, put one feet on the wheel and push it by 2 or 3 CENTIMETER left or right never more ..
boat 72', 58t, speed 9.8kts, wind 8/10 kts by the side and small swell in another direction.
 
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