GPS to Bow thruster

scoty said:
Why do thrusters need to be electrically powered,,,,I am a suporter of hydraulic pumps/drives, proved over many years in industrial/agricultural and other industries to be very reliable, needing only a little operator maintenance........I will also say, in my opinion boat propellors thrashing around in water ,,are as much use as aircraft propellors, in todays world, we just need to develope existing propulsion systems for motor or should I say powered boats,,,,,,,,,another point,,,,,water jets are more economic,safer also low maintenance than large metal lumps that are needed to turn shafts and propellors........
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I'm confused. This discussion is the same whether the b/thruster is electric or hydraulic. Sure, plenty of people have referred to electric because they are common, but the basic discussion on a b/thruster as an a/pilot remains the same

As regards water jets, they still have a shaft, propeller/impeller and a big engine to turn the shaft. Or are you thinking of something else like diesel fired gas turbine engines to drive the jet (you'd still have the shaft and impeller even then, and certainly not low maintenance)
 
A bow thruster is only any use at fairly slow speed I would guess two to three knots max.

Yes hydraulic would get over the overheating and high electric draw of an electric unit.

Why use a bow thruster to steer, use rudder or possibly a bow rudder as well as used by some short hop ferries.

A stern rudder on a single shaft boat or a pair of stern rudders on twin shaft work well for me with Autopilots however.
 
Transverse tunnel thrusters have negligible impact on directional motion above 3 knots and no impact at all above six knots. The cavitation within the tunnel whilst underway will have huge impacts on thruster prop load if run and in turn aggressive loads on both shaft bearings and seals. To protect against this most modern vessels have either electrical or mechanical interlocks which prevent the thruster breaker or hydraulic pumps being started above six knots. Whether you powered the thruster with electricity or with hydraulics you would only end up tripping breakers, lifting relief valves or burning out motors.
If you must steer your boat by means other than a rudder then you should consider azimuth thrusters. I have no idea if they can be bought in small enough form to suit a pleasure craft? Azimuth thruster are most efficient at the aft end of a vessel but can be mounted forward of midships in a configuration known as azimuth tractor drive (ATD).
Tractor drives are arranged as such to increase safety and manoeuvring whilst working with towing loads over the stern. However there is a huge trade off in steering efficiency whilst underway in a forward direction. To counter this many Azimuth Tug boats are now arranged with stern mounted Azimuth thrusters (Known as Azimuth Stern Drive, ASD) and work the towing loads over the bow.
However neither of these configurations are particularly efficient in forward motion and are only used where manoeuvrability is a priority. They would be ridiculously complicated to fit in a pleasure craft and in truth fairly pointless. A further option is a Cyclodial Drive or Voith Schneider Drive. These are only available from voith and I doubt in the size you would need. They are quite complex to manufacture and maintain. they have two main uses; applications requiring high manoeuvrability or where a low noise signature is required such as in Mine Sweeping.
If your planning a high speed application then a water jet drive may interest you but you loose some low speed manoeuvring.
If you need extra thrust then a ducted conventional propeller such as a Kort Nozzle could suit but above 15 knots you start losing efficiency.
Basically if you are a normal leisure boater sailing a normal leisure boat then I would recommend a conventional propeller, conventional rudder and a conventional bow thruster, for slow manoeuvres, linked with a conventional auto pilot. If you like gadgets have a look at Twin Disc's Express Joystick System.
https://www.youtube.com/watch?v=fP9QAemSKp8
 
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cryan said:
Transverse tunnel thrusters have negligible impact on directional motion above 3 knots and no impact at all above six knots. The cavitation within the tunnel whilst underway will have huge impacts on thruster prop load if run and in turn aggressive loads on both shaft bearings and seals. To protect against this most modern vessels have either electrical or mechanical interlocks which prevent the thruster breaker or hydraulic pumps being started above six knots. Whether you powered the thruster with electricity or with hydraulics you would only end up tripping breakers, lifting relief valves or burning out motors.
If you must steer your boat by means other than a rudder then you should consider azimuth thrusters. I have no idea if they can be bought in small enough form to suit a pleasure craft? Azimuth thruster are most efficient at the aft end of a vessel but can be mounted forward of midships in a configuration known as azimuth tractor drive (ATD).
Tractor drives are arranged as such to increase safety and manoeuvring whilst working with towing loads over the stern. However there is a huge trade off in steering efficiency whilst underway in a forward direction. To counter this many Azimuth Tug boats are now arranged with stern mounted Azimuth thrusters (Known as Azimuth Stern Drive, ASD) and work the towing loads over the bow.
However neither of these configurations are particularly efficient in forward motion and are only used where manoeuvrability is a priority. They would be ridiculously complicated to fit in a pleasure craft and in truth fairly pointless. A further option is a Cyclodial Drive or Voith Schneider Drive. These are only available from voith and I doubt in the size you would need. They are quite complex to manufacture and maintain. they have two main uses; applications requiring high manoeuvrability or where a low noise signature is required such as in Mine Sweeping.
If your planning a high speed application then a water jet drive may interest you but you loose some low speed manoeuvring.
If you need extra thrust then a ducted conventional propeller such as a Kort Nozzle could suit but above 15 knots you start losing efficiency.
Basically if you are a normal leisure boater sailing a normal leisure boat then I would recommend a conventional propeller, conventional rudder and a conventional bow thruster, for slow manoeuvres, linked with a conventional auto pilot. If you like gadgets have a look at Twin Disc's Express Joystick System.
https://www.youtube.com/watch?v=fP9QAemSKp8
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Thanks, your reply is the most intersting and usefull, I recently contacted an American aimuth thruster maker with my boat spec. and now wait for cost etc
 
scoty said:
I recently contacted an American aimuth thruster maker with my boat spec. and now wait for cost etc
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Your previous comments made me curious, but this one is even more intriguing.
Unless I lost the plot completely, my understanding was that you are thinking to use the b/t (which you already have) as a mean of keeping your course without fitting an a/p (which you don't have).
And now you're considering the installation of an azipod?!?
Frankly speaking, if this isn't a troll, it sure looks like one...
 
Surely there are, as suggested far more practical and cheaper methods of autopilot. Is this the function that you require.... Or dynamic positioning.
Contact kongsberg for DP systems, industry standard, in fact maybe go the whole hog and ask for class 3. They will supply DGPS systems, fan beam and taughtwire.... Maybe im reading this wrong, but cant help thinking your trying to reinvent the wheel, or barking up the wrong tree.... Or just barking :)
Not sure kongsberg will have anything to suit anything smaller than about a couple of thousand tonnes though... Fwiw...
Definitly odd question with not much reasoning, imho....
 
The OP could fit a water cannon on the bow. If the GPS wants to turn to starboard, just point the thing to port and fire. And v. v.
 
Seems to be companies thinking also that traditionally done thrusters, steering systems, propulsion systems need improving, my original enquiry is producing usefull information, so maybe we will have more reliable auto pilots and better propulsion than propellors thrashing around in water.
 
MapisM said:
Frankly speaking, if this isn't a troll, it sure looks like one...
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Yes this has got to be a troll. The original answer sought was in his own words "simple". He wanted to find a short cut around installing an autopilot. Now he has asked someone (whose time is being wasted) for a quote for retrofittable Azipods. Some short cut!
 
scoty said:
Seems to be companies thinking also that traditionally done thrusters, steering systems, propulsion systems need improving, my original enquiry is producing usefull information, so maybe we will have more reliable auto pilots and better propulsion than propellors thrashing around in water.
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Yup, maybe, who knows?
Time being, I'm linking this thread in my agenda, on June 16th, 2064.
I'll be 100+ yo by then, but hopefully in my nursing home there will be some other forumites who will remember this epic thread... :)
 
scoty said:


1. I posted this on another site but maybe that was a mistake so I try here,

2. For me the bow thruster works well as a course corrector and is reliable and simple.
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1. 'Wonder which sites they were. :ambivalence:

2. For me the rudder works well as a course corrector, very simple and even more reliable! :cool:

I think you must have been watching the film "Speed2" where they tried to turn a cruise ship with a bow thruster...

Great fun thread tho... :p

RR
 
scoty said:
Exactly, that is what a Dutch company is producing, ie. water jet bow and stern thrusters, that work silently, no cavitation etc etc
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It looks like they are trying to solve a problem that doesn't exist. Why can't you use a rudder and a conventional autopilot?
 
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