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Old 08-20-2016, 10:14 PM   #141
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Bow Thruster vs Stern Thruster

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Originally Posted by Great Laker View Post
I am in the camp that if I could only have one thruster it would be a stern. I can put the nose in against the dock, stop forward momentum, and push the stern over without moving forward or backward. Plus, I can steer the boat with the stern thruster while backing out of a narrow channel with the stern thruster as well. Consider putting in just the stern and trying it that way. You might find you don't need to spend more on a bow thruster.

I am the opposite. If I had to choose one I would take a bow thruster. With a single engine boat I can move the stern sideways some with rudder and throttle. While I can point the bow, I can't move it sideways without a thruster.

Edit. Sorry about the duplicate. Bad cell connection.
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Old 08-20-2016, 11:29 PM   #142
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I am the opposite. If I had to choose one, it would be a bow thruster. I can move move the stern sideways a little with throttle and rudder. With a single engine boat I can point the bow, but not move the bow sideways without a thruster.
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Old 08-21-2016, 06:46 AM   #143
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"With a single engine boat I can point the bow, but not move the bow sideways without a thruster'

Our launch pivots about 2/3 back from the bow.

So moving the bow does require moving the stern with prop walk , and basically in only one direction.
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Old 08-21-2016, 06:55 AM   #144
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I have a 34 Marine Trader with a bow thruster. There is no way I would ever have a single screw without one. My bought also has a Lehman 120. This picture is before I bought her and started repairs.

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Old 08-21-2016, 07:14 AM   #145
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Interesting thread. I've repaired bow thrusters for friends but I've never used one...
Our current sailboat, due to its fin keel/spade rudder configuration, is so easy to direct both in forward and reverse, that we never even considered the option. Our previous sailboat was a centerboard/full keel with an attached rudder. That was a horse of a different color! In reverse, it would go backwards. Sometimes to port and sometimes to starboard. We eventually learned to control the beast but it was challenging! I remember a friend of mine who is a licensed captain watching me one day and reprimanding me for my technique. He decided that he would take me out for a few lessons...
2 hours later he walked away from the helm and said the boat was possessed!

Anyway, as the American Tug comes equipped with a bow thruster and we are spending all of this money anyway...we have elected to equip her with a stern thruster too. The memories of that sailboat made it an easy decision!
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Old 08-21-2016, 11:34 AM   #146
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Quote:
Originally Posted by Bruce B View Post
Interesting thread. I've repaired bow thrusters for friends but I've never used one...
Our current sailboat, due to its fin keel/spade rudder configuration, is so easy to direct both in forward and reverse, that we never even considered the option. Our previous sailboat was a centerboard/full keel with an attached rudder. That was a horse of a different color! In reverse, it would go backwards. Sometimes to port and sometimes to starboard. We eventually learned to control the beast but it was challenging! I remember a friend of mine who is a licensed captain watching me one day and reprimanding me for my technique. He decided that he would take me out for a few lessons...
2 hours later he walked away from the helm and said the boat was possessed!

Anyway, as the American Tug comes equipped with a bow thruster and we are spending all of this money anyway...we have elected to equip her with a stern thruster too. The memories of that sailboat made it an easy decision!
Bruce

You won't be sorry. Your experience with a full keel sailboat will help you I think when you start to drive your new boat. I do miss the way my sailboat would spin in a dime in forward or reverse. As I have gotten more experience, back and fill does work pretty well depending on the wind and current.
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Old 08-21-2016, 12:12 PM   #147
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I do miss the way my sailboat would spin in a dime in forward or reverse.
Ditto. I didn't know how good I had it then. (At least in this particular instance.)
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Old 08-21-2016, 12:38 PM   #148
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Quote:
Originally Posted by Bruce B View Post
Interesting thread. I've repaired bow thrusters for friends but I've never used one...
Our current sailboat, due to its fin keel/spade rudder configuration, is so easy to direct both in forward and reverse, that we never even considered the option. Our previous sailboat was a centerboard/full keel with an attached rudder. That was a horse of a different color! In reverse, it would go backwards. Sometimes to port and sometimes to starboard. We eventually learned to control the beast but it was challenging! I remember a friend of mine who is a licensed captain watching me one day and reprimanding me for my technique. He decided that he would take me out for a few lessons...
2 hours later he walked away from the helm and said the boat was possessed!

Anyway, as the American Tug comes equipped with a bow thruster and we are spending all of this money anyway...we have elected to equip her with a stern thruster too. The memories of that sailboat made it an easy decision!
Bruce
We saw a number of ATs while in the Broughtons this summer. All had both and several had the control station in the cockpit for backing down. Very nice and something we will do when we add the stern thruster.
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Old 08-21-2016, 01:04 PM   #149
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We saw a number of ATs while in the Broughtons this summer. All had both and several had the control station in the cockpit for backing down. Very nice and something we will do when we add the stern thruster.
I saw one boat with a cockpit control station and didn't understand why it was there! Now it makes more sense. We will not have that option but I'm guessing that the visibility to the rear is good enough to get by. I have a friend who owned a Nordhavn 40 and that boat had virtually no clear view aft. He needed a camera to see what was happening behind him.
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Old 08-21-2016, 02:41 PM   #150
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I have a friend who owned a Nordhavn 40 and that boat had virtually no clear view aft. He needed a camera to see what was happening behind him.
Bruce
I have the same
installed these, one in the engine room and one out back
2X 18 IR LED CCD Reverse Camera 7" LCD Monitor CAR Rear View KIT 2X 10M Cable | eBay

Work great, only annoyance is the red yellow green reversing lines.
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Old 08-21-2016, 02:46 PM   #151
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I have the same
installed these, one in the engine room and one out back
2X 18 IR LED CCD Reverse Camera 7" LCD Monitor CAR Rear View KIT 2X 10M Cable | eBay

Work great, only annoyance is the red yellow green reversing lines.
That is essentially what he had too.
I'm sure I'd get accustomed to it...not sure how long it would take!
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Old 08-21-2016, 03:06 PM   #152
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We have a camera aimed aft as well. We have poor visibility aft from the Pilothouse. There was a NP42 for sale in AK that had a control station in the aft cockpit. Nice feature.
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Old 08-21-2016, 03:59 PM   #153
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The ones I saw were factory installed.
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Old 08-21-2016, 09:40 PM   #154
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Just out of curiosity, is the stern thruster the same size as the bow thruster on a boat? It would seem that there generally is more boat below the surface in the stern than in the bow.

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Old 08-21-2016, 10:00 PM   #155
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Just out of curiosity, is the stern thruster the same size as the bow thruster on a boat? It would seem that there generally is more boat below the surface in the stern than in the bow.

Ted
We installed identical 13 HP Wesmar thrusters on Blue Sky, and I can't say that there is a noticeable difference in the forces provided.

One thing that is obvious when using the thrusters is the concept of equal and opposite reactions. I.e., if you use the stern thruster for example, the bow moves in the opposite direction, at least on our NT 42. Meaning that I seldom use just one thruster as Blue Sky otherwise tends to spin on her own axis.

Also, for some reason that escapes me, when just using the stern thruster the boat moves backwards. I'm sure there's a technical reason for that.
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Old 08-21-2016, 10:36 PM   #156
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We installed identical 13 HP Wesmar thrusters on Blue Sky, and I can't say that there is a noticeable difference in the forces provided.

One thing that is obvious when using the thrusters is the concept of equal and opposite reactions. I.e., if you use the stern thruster for example, the bow moves in the opposite direction, at least on our NT 42. Meaning that I seldom use just one thruster as Blue Sky otherwise tends to spin on her own axis.

Also, for some reason that escapes me, when just using the stern thruster the boat moves backwards. I'm sure there's a technical reason for that.
Have you considered changing the brand of grog you drink while docking?...or maybe the issue is the lack of grog
I'm sorry I couldn't help that remark. Your information is appreciated as I have never owned a vessel with thrusters besides the main engines. Now I'm curious if what you describe is the same for all vessels?
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Old 08-21-2016, 10:42 PM   #157
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Have you considered changing the brand of grog you drink while docking?...or maybe the issue is the lack of grog
I'm sorry I couldn't help that remark. Your information is appreciated as I have never owned a vessel with thrusters besides the main engines. Now I'm curious if what you describe is the same for all vessels?
In my less than scientific analysis, I'd have to say that changing from rum & coke to manhattans made no difference!

No idea if other vessels act the same way, as I haven't done a grog survey on them....
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Old 08-21-2016, 11:16 PM   #158
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In my less than scientific analysis, I'd have to say that changing from rum & coke to manhattans made no difference!

No idea if other vessels act the same way, as I haven't done a grog survey on them....
Hummm...maybe you should apply for a government grant to research this subject. If you do so I will volunteer to be one of your test subjects
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Old 08-21-2016, 11:45 PM   #159
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....
Also, for some reason that escapes me, when just using the stern thruster the boat moves backwards. I'm sure there's a technical reason for that.
Conrad, I'll stick my physics neck out here and suggest it is because the thruster is forcing water away from the stern on the one side, while sucking it in from the intake side, with the net effect being a bit like a that of yacht sail, creating in effect a modest negative pressure area behind the stern, which draws the vessel into it. Just a thought....others..?

As to whether to have thrusters or not. I don't, and we manage. But if I was going upscale in size and price, sure, I'm not to proud to use them, and would definitely want them. Both, front and back for the reasons you just mentioned.

I see the issue as similar to how we all managed with vehicles that did not have power mirrors and windows, central remote locking, reversing cameras, etc, etc. Now having had them, we realise they add to the safety and convenience of use, so why would you not..? Hey those powered tailgates seem a good idea. Now I don't have one of those. But when your arms are full...
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Old 08-22-2016, 01:30 AM   #160
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Conrad, I'll stick my physics neck out here and suggest it is because the thruster is forcing water away from the stern on the one side, while sucking it in from the intake side, with the net effect being a bit like a that of yacht sail, creating in effect a modest negative pressure area behind the stern, which draws the vessel into it. Just a thought....others..?

As to whether to have thrusters or not. I don't, and we manage. But if I was going upscale in size and price, sure, I'm not to proud to use them, and would definitely want them. Both, front and back for the reasons you just mentioned.

I see the issue as similar to how we all managed with vehicles that did not have power mirrors and windows, central remote locking, reversing cameras, etc, etc. Now having had them, we realise they add to the safety and convenience of use, so why would you not..? Hey those powered tailgates seem a good idea. Now I don't have one of those. But when your arms are full...
I like your thoughts on why there is a pull backwards; it fits with my physics and ultralight classes from way back when.

We have a side tie berth facing east west and we are on the south side. An 89 footer sits right in front of us, and a 70 footer right behind. With a north wind of any consequence, you are not going to dock without thrusters. (No dock cleats, only bull rails). So yes, the thrusters are very worthwhile. Even better when your dock neighbours know you have them and you don't use them....

But they also come in handy in unexpected ways such as last winter when we woke up at anchor and were iced in on three sides. The thrusters allowed us to slip out sideways with aplomb.
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