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08-20-2016, 10:14 PM
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#141
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Guru
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
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Bow Thruster vs Stern Thruster
Quote:
Originally Posted by Great Laker
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.
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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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08-20-2016, 11:29 PM
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#142
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Guru
City: San Diego
Vessel Name: Circuit Breaker
Vessel Model: 2021..22' Duffy Cuddy cabin
Join Date: Oct 2007
Posts: 6,691
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Quote:
Originally Posted by dhays
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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__________________
Done with diesel power boats! Have fallen in love with all electric!
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08-21-2016, 06:46 AM
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#143
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Guru
Join Date: Oct 2007
Posts: 22,553
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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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08-21-2016, 06:55 AM
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#144
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Veteran Member
City: Cincinnati
Vessel Name: Liberty 2
Vessel Model: DeFever 43
Join Date: Nov 2015
Posts: 66
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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.
Sent from my iPad using Trawler Forum
Raymond Goff
1978 Marine Trader 34
Www.libertytrawler.com
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08-21-2016, 07:14 AM
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#145
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Guru
Join Date: Jun 2014
Posts: 1,274
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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!
Bruce
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08-21-2016, 11:34 AM
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#146
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Guru
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
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Quote:
Originally Posted by Bruce B
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
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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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08-21-2016, 12:12 PM
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#147
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Guru
City: Newark, DE
Vessel Name: Infinity
Vessel Model: Kadey Krogen 48
Join Date: Jan 2015
Posts: 709
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Quote:
Originally Posted by dhays
I do miss the way my sailboat would spin in a dime in forward or reverse.
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Ditto. I didn't know how good I had it then. (At least in this particular instance.)
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08-21-2016, 12:38 PM
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#148
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Senior Member
City: Union, WA
Vessel Name: Touch of Grey
Vessel Model: Nordic Tug 42
Join Date: Aug 2015
Posts: 115
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Quote:
Originally Posted by Bruce B
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
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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.
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08-21-2016, 01:04 PM
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#149
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Guru
Join Date: Jun 2014
Posts: 1,274
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Quote:
Originally Posted by bcam
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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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.
Bruce
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08-21-2016, 02:41 PM
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#150
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Guru
City: Queensland
Vessel Model: Milkraft 60 converted timber prawn trawler
Join Date: Jul 2016
Posts: 5,482
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Quote:
Originally Posted by Bruce B
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
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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.
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08-21-2016, 02:46 PM
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#151
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Guru
Join Date: Jun 2014
Posts: 1,274
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Quote:
Originally Posted by Simi 60
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That is essentially what he had too.
I'm sure I'd get accustomed to it...not sure how long it would take!
Bruce
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08-21-2016, 03:06 PM
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#152
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Guru
City: Gig Harbor
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 9,046
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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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08-21-2016, 03:59 PM
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#153
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Senior Member
City: Union, WA
Vessel Name: Touch of Grey
Vessel Model: Nordic Tug 42
Join Date: Aug 2015
Posts: 115
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The ones I saw were factory installed.
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08-21-2016, 09:40 PM
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#154
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Guru
City: Fort Myers, FL... Summers in the Great Lakes
Vessel Name: Slow Hand
Vessel Model: Cherubini Independence 45
Join Date: Dec 2010
Posts: 12,834
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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
__________________
Blog: mvslowhand.com
I'm tired of fast moves, I've got a slow groove, on my mind.....
I want to spend some time, Not come and go in a heated rush.....
"Slow Hand" by The Pointer Sisters
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08-21-2016, 10:00 PM
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#155
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Guru
City: Campbell River
Vessel Name: Blue Sky
Vessel Model: Nordic Tugs 42 Hull #001
Join Date: Oct 2007
Posts: 1,972
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Quote:
Originally Posted by O C Diver
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
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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.
__________________
Conrad
Berthed in
Campbell River BC
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08-21-2016, 10:36 PM
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#156
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Guru
City: coos bay
Join Date: Oct 2012
Posts: 1,290
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Quote:
Originally Posted by Conrad
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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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?
__________________
B
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08-21-2016, 10:42 PM
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#157
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Guru
City: Campbell River
Vessel Name: Blue Sky
Vessel Model: Nordic Tugs 42 Hull #001
Join Date: Oct 2007
Posts: 1,972
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Quote:
Originally Posted by bfloyd4445
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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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....
__________________
Conrad
Berthed in
Campbell River BC
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08-21-2016, 11:16 PM
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#158
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Guru
City: coos bay
Join Date: Oct 2012
Posts: 1,290
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Quote:
Originally Posted by Conrad
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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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
__________________
B
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08-21-2016, 11:45 PM
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#159
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TF Site Team
City: Ex-Brisbane, (Australia), now Bribie Island, Qld
Vessel Name: Now boatless - sold 6/2018
Vessel Model: Had a Clipper (CHB) 34
Join Date: Jun 2008
Posts: 10,101
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Quote:
Originally Posted by Conrad
....
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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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...
__________________
Pete
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08-22-2016, 01:30 AM
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#160
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Guru
City: Campbell River
Vessel Name: Blue Sky
Vessel Model: Nordic Tugs 42 Hull #001
Join Date: Oct 2007
Posts: 1,972
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Quote:
Originally Posted by Peter B
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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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.
__________________
Conrad
Berthed in
Campbell River BC
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