Bow thruster vs Stern thruster

[jclays]

Good morning
Looking at Trawlers in the 38ft range. Started looking at single screws as well as the twin screws. I noticed some single screw trawlers had bow thrusters and other only a stern thruster. Id like info on both from those who have them. Which is preferred and why one is preferred over the other.
Thanks
Jim

 

[OldDan1943]

AT comes with bow and stern thrusters.

 

[diver dave]

my random thoughts:
Many boats when left to the wind, turn the bow downwind, and it's difficult for a single to "fix" that in limited space. So, it seems the bow thruster would be best for that scenario.
OTOH, some stern thrusters designs are mounted independant of the hull, avoiding that grief, and can be more easily maintained. Reportedly, some can act as forward thrusters, when the prime mover dies; but I'd predict speed is really slow.
Yep, nice to have both!

 

[Tom.B]

Please do a forum search. This topic has been hashed out (and to death) as many times as an anchor discussion. It never goes well ;-)

 

[Shrew]

Honestly, I've heard of bow thruster only OR Bow and Stern thrusters. I've never seen or heard of stern thruster only. I can't even imagine this being very effective. I have a bow thruster on my single inboard. I'd love to have a stern thruster as well. Over time, I've learned to live without a stern thruster and there are now only a few rare instances where I find it is almost necessary.

I wouldn't want to own a single inboard with NO thruster at all. However, you can learn to be very effective with the 'bump and fill' technique.

 

[Oldersalt]

Sorry, but a stern thruster only works just fine! My Grand Banks 32 came with one. In close quarters manuevering it does a great job of shoving the stern around. Because it is hydraulic rather than electric, there is no limitation on how long you can run it, when necessary (as you know, most electric thrusters can only run a minute or two before overheating). Also, installation is easier...no big hole through the bow, just some bolts and a couple of hydraulic lines through the transom.
Best
Oldersalt

Honestly, I've heard of bow thruster only OR Bow and Stern thrusters. I've never seen or heard of stern thruster only. I can't even imagine this being very effective. I have a bow thruster on my single inboard. I'd love to have a stern thruster as well. Over time, I've learned to live without a stern thruster and there are now only a few rare instances where I find it is almost necessary.

I wouldn't want to own a single inboard with NO thruster at all. However, you can learn to be very effective with the 'bump and fill' technique.

 

[Irish Rover]

This is an interesting subject and I'm keen to hear the opinions of more experienced members. It's a bit off putting [especially for new posters] to be told go search the forum when they start a new thread. If you've heard it all before then skip the thread and let others get the benefit of the experience of those who are happy to share.

 

[Sealife]

Having put over 4000 hrs on single screw no thruster boats, my opinion:

Stern thrusters only is a cheaper way of adding some control. I feel it is a bit wasted, as I’ve never not been able to control my stern (lots of practice).

Bow thruster would be great, just haven’t had a boat with one, and decided the cost wasn’t worth it after being used to not having one.

Both with a joystick would be heaven, but for me not worth the cost or maintenance etc.

When I had my first single screw inboard, I didn’t know how I was going to manage docking. But being on the water in the Chesapeake bay, I watched the commercial waterman dock all the time with bigger boats and single screws. If they could do it, so could I. Practice, practice, practice.

That way when your thruster(s) don’t work, you won’t be completely screwed.

 

[Nomad Willy]

When I was longing for a thruster it was for a stern thruster. What made me want a thruster at all was so often when anchoring the wind would blow the bow off so soon my boat was abeam to the wind and the anchor rode was at right angles to the boat. Wished I could bring the stern around behind the bow (wind wise) to anchor normally.

I decided in the end a bow thruster would do as well or better. As Diver Dave says the bow falls off downwind. The reason being the freeboard is much greater at the bow and the side area of the hull underwater is less than aft on most boats. Hence the popularity of “bow thrusters”.

Add to the fact that we already have stern thrusters (rudder) the bow thruster seems most important or desirable of the two. But obviously both would be better. Or a bigger better bow thruster. You’re the buyer Jim. You’re in the driver’s seat.

 

[Chrisjs]

Apart from helping turn the boat around using both bow and stern thrust, the only other use of the stern thruster was to push the stern into the dock to help with lines after the bow line was attached. The bow thruster did most of the work. The stern thruster was of marginal value. Logically, it is much harder to move the stern sideways rather than turn the bow, and to do so effectively takes a lot more thrust. I think many stern thrusters are simply under-powered to help much. The imaginary concept of moving the vessel sideways using bow and stern thrust is simply that - imaginary - unless you own the Queen Mary!!

 

[Nomad Willy]

This is an interesting subject and I'm keen to hear the opinions of more experienced members. It's a bit off putting [especially for new posters] to be told go search the forum when they start a new thread. If you've heard it all before then skip the thread and let others get the benefit of the experience of those who are happy to share.

I agree w that mostly IR,
But I advise to go search at times when,
1. The older thread was much more comprehensive and more informative.
2. When the older thread contained specific information that I could not recall and didn’t want to do the work for the newer member.
3. Most often though I identify w the newer member because the search engine is so poor. Perhaps I just don’t know what I’m doing as is often the case on the internet.

 

[jclays]

This is an interesting subject and I'm keen to hear the opinions of more experienced members. It's a bit off putting [especially for new posters] to be told go search the forum when they start a new thread. If you've heard it all before then skip the thread and let others get the benefit of the experience of those who are happy to share.

Thanks..My thoughts exactly.

 

[SaltyDawg86]

Honestly, I've heard of bow thruster only OR Bow and Stern thrusters. I've never seen or heard of stern thruster only. I can't even imagine this being very effective. I have a bow thruster on my single inboard. I'd love to have a stern thruster as well. Over time, I've learned to live without a stern thruster and there are now only a few rare instances where I find it is almost necessary.

I wouldn't want to own a single inboard with NO thruster at all. However, you can learn to be very effective with the 'bump and fill' technique.

I looked at an OA that was a single screw and only a stern thruster. As said, the stern thruster seems easier to install and cheaper.

I'm not trying to step on anyone's toes, but, IMO a stern thruster and no bow thruster serves no point and is a waist of money. The rudder on a single screw does the same thing and on a twin screw... Well life is easy on them. A bow thruster is the better decision by far.

 

[SaltyDawg86]

The imaginary concept of moving the vessel sideways using bow and stern thrust is simply that - imaginary - unless you own the Queen Mary!!

Lol I have to completely disagree with that statement. Hundreds, if not thousands of vessels use a bow and stern thruster every day to dock and undock without the assistance of tugs. What makes you believe it's "imaginary" unless you're on the QM?

 

[psneeld]

and I guess a positioning system is for unicorns too...

 

[Moby Nick]

One big reason I chose an old Albin-25 with a single fixed screw was because I was hugely impressed with how Maine Lobstermen handle their boats, and wanted to try my hand at it. We had no prior power boat experience, just outboard sailing auxiliary, which of course is a steerable prop. We getting reasonably good at handling our Albin in close quarters and have no need for thrusters..

 

[diver dave]

I see at least some commercial guys (longliners come to mind) that tend to have, shall we say, more acceptance to violent dock impacts than a lot of yachties desire to have.

So, when I hear such and such a commercial operators do just fine with limited controls, I take that will some grain of salt. Notwithstanding the fact, that these guys do this in all kinds of wind and are well practiced. Nonetheless, they are not worried with polishing the bell every week and rub rail dent repair.
OK, flame suit on!

 

[Rebel112r]

On the North Pacific, with both bow an stern thrusters of equal strength, I find the stern thruster moves its end more easily, more push with less effort. Flat rear section of stern, plus being at the extreme end, compared with bow thruster, that is a bit aft and has to push the more vertical forefoot of the bow. I would like to have a larger bow thruster, the stern thruster seems well sized. Also with a helm that takes 5 turns lock to lock, it is a bit of a challenge to move rudder lock to lock to move stern in opposite direction. With stern thruster you can leave the rudder hard over say to port to move the stern to stbd with power, and use thruster to correct to port or vice versa. A jog stick to move rudder quickly would be nice, I can do it with the autopilot control but it is 2 many buttons to push when trying to maneuver in marinas. With twin engines, the need for a stern thruster, is questionable, but still would be nice to have.

 

[AusCan]

You learn to deal with whatever you have, whether it be bow thruster, stern thruster, twin engines, or single fixed prop. With enough practice (and a good rudder) they can all do the same thing.

In regard to the choice of bow or stern thruster, go with whatever is best suited for installation on your particular boat.

 

[Nomad Willy]

When I was longing for a thruster it was for a stern thruster. What made me want a thruster at all was so often when anchoring the wind would blow the bow off so soon my boat was abeam to the wind and the anchor rode was at right angles to the boat. Wished I could bring the stern around behind the bow (wind wise) to anchor normally.

I decided in the end a bow thruster would do as well or better. As Diver Dave says the bow falls off downwind. The reason being the freeboard is much greater at the bow and the side area of the hull underwater is less than aft on most boats. Hence the popularity of “bow thrusters”.

Add to the fact that we already have stern thrusters (rudder) the bow thruster seems most important or desirable of the two. But obviously both would be better. Or a bigger better bow thruster. You’re the buyer Jim. You’re in the driver’s seat.

The “edit” period went so fast I need to quote myself.

Another thought occured to me. In the anchoring situation I was talking about getting knocked back/down w the wind at the bow the boat will assume a position somewhat broadside to the wind. Even if only 45 degrees the bow thrusters will need to push against the wind on the bow whereas the stern thrusters would be aided by the wind force. So the stern thruster may have as much effect as the bow thruster. So re the experience rebel112r one would almost need to find an owner w the same boat or guess or get both and find out. One advantage w both is that both in operation at once pushing in opposite directions would probably rotate the boat quite smartly. I would like that but $.

 

[OldDan1943]

I am fortunate in that the AT comes with a bow and stern thruster but......
learn which way your stern 'casts' backing down and take advantage of it.
No one said you have to dock perfectly at first go. Back out and aim better.
Also, learn to use spring lines. Spring line will really help with a single screw boat.

 

[Nightsky]

"Bow thruster vs Stern thruster" as in you can only pick one? Bow thruster, for sure.

 

[jleonard]

Honestly, I've heard of bow thruster only OR Bow and Stern thrusters. I've never seen or heard of stern thruster only. I can't even imagine this being very effective. I have a bow thruster on my single inboard. I'd love to have a stern thruster as well. Over time, I've learned to live without a stern thruster and there are now only a few rare instances where I find it is almost necessary.

.

I also have a hydraulic stern thruster only. It IS effective. I can put the boat anywhere I need to.
Is a bow thruster more effective? I used to think so but now I'm not so sure.
I see you are out of Westerly, I am out of Mystic. Next summer when you see "Attitude Adjustment" anchored up at Napatree, come on over and I'll demo.

My ex boat was a single screw old Mainship model 1. I ran it for 14 years with no thruster. It was no big deal, but it would have made some situations easier.

 

[markpierce]

With a bow thruster and a keel deepest at the stern, my boat (single-engine, bow thruster) can rotate in-place.

 

[dhays]

Until this thread I was not aware of anyone that had a stern thruster only.

I have both on my boat and like them. The Bow thruster is much more useful to me than the stern as I can move the stern with throttle and rudder.

 

[jclays]

Thanks for the input. I currently own a twin screw boat and am looking at trawlers prior to my retirement after next year. I've encountered some nice boats however being single screw scared me off until I started thinking of thrusters. Twins I'm not not worried. I can almost walk my boat with the throttle controls.

 

[Shrew]

I also have a hydraulic stern thruster only. It IS effective. I can put the boat anywhere I need to.
Is a bow thruster more effective? I used to think so but now I'm not so sure.
I see you are out of Westerly, I am out of Mystic. Next summer when you see "Attitude Adjustment" anchored up at Napatree, come on over and I'll demo.

Interesting question. I have no idea which is more effective. I suppose you'd have to try each to find out. The problem is, I think you'd really need to run each for a while to really get each dialed in.

We're at Napatree almost every weekend. Now you're never going to get rid of us.

 

[gaston]

Its very hard to argue both is the best

 

[markpierce]

Its very hard to argue both is the best

Unnecessary systems cost and are one thing more to go wrong.

 

[BruceK]

As someone who has neither but lusts after bowthrusters, I`d say it depends on whether you have twins or single (hey, we could discuss that too!). With twins you can move the stern either way, a bowthruster complements that. With a single, thrusters both ends would be good.
2 contributors have hydraulic thrusters. Do you mean water jet type, or hydraulic driven? I`d like to know more, the install would be a lot simpler. Maybe needs a new thread.