Bow thruster recommendations please

[Top cat]

I'm  specifying  equipment for a new 68' steel community narrowboat which will probably weigh something in the order of 22 tons. The boat is operated by volunteers  some of whom are inexperienced with bow thrusters.   The  trustees have decided that it is to be fitted with an electric bow thruster to aid turning in very confined spaces probably with floating debris.

Does anyone have any recommendations for a  suitable system?  How much force should we aim for?  

I've  seen the Vetus rim drive which cllaims unlimited run time but haven't  found  a price which tends to suggest its extortionate 

Any advice on making  it fool proof?  I'm  envisioning  a timer to prevent over use.

[mrsmelly]

42 minutes ago, Top cat said:

I'm  specifying  equipment for a new 68' steel community narrowboat which will probably weigh something in the order of 22 tons. The boat is operated by volunteers  some of whom are inexperienced with bow thrusters.   The  trustees have decided that it is to be fitted with an electric bow thruster to aid turning in very confined spaces probably with floating debris.

Does anyone have any recommendations for a  suitable system?  How much force should we aim for?  

I've  seen the Vetus rim drive which cllaims unlimited run time but haven't  found  a price which tends to suggest its extortionate 

Any advice on making  it fool proof?  I'm  envisioning  a timer to prevent over use.

My last boat had a vetus bow thruster and one of the trip boats I skippered on the Trent had vetus also ( 80 ton boat ) Whilst I consider the price of vetus kit to be extortionate and their engine marinisation to be questionable my personal experience with their electric bowthrusters was a positive one and especialy the larger one on the trip boat 86feet by 18 feet was used not often but in anger when needed without fault. Hope this helps. They do many sizes and I cannot remember what the two I used were.

[David Mack]

This model has a particularly low electricity consumption.

[blackrose]

I would normally say that a properly installed electric BT is fine in the hands of those who don't overuse it. However, on a community boat I can't help thinking that might be unlikely and they will soon flatten the BT batteries or burn out the motor.  

[Neil Smith]

I was thinking that aswell, so would advise a hydraulic on instead.

Neil

[mrsmelly]

6 minutes ago, Neil Smith said:

I was thinking that aswell, so would advise a hydraulic on instead.

Neil

Hydraulic are much better if installed correctly. However the maintainance can be onerous and if run off the main engine as is usual with small boats such as narrowboats then power is lost for the main drive often when its most needed. One of the boats I skippered on the Trent had hydraulic bow thruster that ran off both the main engines ( twin screw ) we lost twenty percent of the propulsion power if we used the thruster. 

[ditchcrawler]

I would suggest hydraulic, you can run it all the while the engine is running. ARS use to do an interesting one in a kinked tube. The red one at the bottom of the page. http://www.arsangliandiesels.co.uk/bow.htm When ARS were Anglia Diesels in Norfolk I use to go there and they tested their bow thrusters in a tank carrying out a static bollard pull. I know nothing about the company that bought them out about 5 or 6 years ago.

[Top cat]

I had considered a hydraulic  one but the only one i have used required the engine to be revved up out of gear to get any grunt out of it. I thought that might lead to the inexperienced  claiming it doesn't  work  or them reving up in gear causing other problems.

 For the electric option I was considering fitting a timer to limit the on time and set a minimum gap between uses. Maybe a relay to only allow operation while the engine is running. But thats all the more to go wrong

Another percieved disadvantage with hydraulics is the need for an uprated gearbox and hyraulic pipes going the length of the boat.

I could be wrong on all of the above and am open to persuasion. If it were left just to me I would use a pole  (if they don't  all go home after Brexit).

 

TOP CAT

[mrsmelly]

2 minutes ago, Top cat said:

I had considered a hydraulic  one but the only one i have used required the engine to be revved up out of gear to get any grunt out of it. I thought that might lead to the inexperienced  claiming it doesn't  work  or them reving up in gear causing other problems.

 For the electric option I was considering fitting a timer to limit the on time and set a minimum gap between uses. Maybe a relay to only allow operation while the engine is running. But thats all the more to go wrong

Another percieved disadvantage with hydraulics is the need for an uprated gearbox and hyraulic pipes going the length of the boat.

I could be wrong on all of the above and am open to persuasion. If it were left just to me I would use a pole  (if they don't  all go home after Brexit).

 

TOP CAT

I think if you set a timer then that could cut out the thruster at the precise moment the steerer realy needed it. I understand the problems with the use of the boat and that some drivers/skippers will be better than others but I dont think a timer is the way to go. We had substantial batteries with a large charger running from mains gennie and found electric was a good option, however we did know what we were doing ( well the MCA says we did )

[NickF]

I skiippered a 65ft x 10ft 6" community boat for about 10 years on a voluntary basis, never needed a bow thruster just always gave thought to current and wind before turning.

[MtB]

I suggest fitting the cheapest bow thruster you can find, which will please the trustees.

Then when (not if) random and untrained users burn it out, not too much money will have been wasted. The consequential benefit is steerers will then figure out how to steer a boat without relying on a BT.

[Tony Fuller]

Some BT's have an overheat sensor coupled to a warning buzzer. In an emergency you can still keep using the Thruster after the buzzer sounds but continued use may burn it out !!!

 

[MtB]

Its hard to imagine an 'emergency' that requires extended use of a bow thruster....

[cuthound]

9 hours ago, Mike the Boilerman said:

Its hard to imagine an 'emergency' that requires extended use of a bow thruster....

Exactly, after over 40 years of hiring and shared boat ownership without bow thrusters,  I bought a boat fitted with a Vetus electric bowthruster. I find I rarely use it (mainly when reversing or winding its windy conditions) and have never needed to use it for longer than about 30 seconds.

It came as standard with a timer which switches it off after perhaps 15 minutes, requiring the thruster to be awitched back on again. This means that it is never available in a hurry, so of little use in a genuine emergency.

Edited March 31, 2017 by cuthound
To unmangle the effects of autocorrect.

[Iain_S]

I sometimes skipper a 60' x 10'6" boat, which was fitted with a bow thruster.

We found it fairly unreliable; if you got yourself into the position of really needing it, that was the time a plastic bag was practically guaranteed to get sucked into it. (Applying a burst of opposite thrust to dislodge said bag usually just made things worse  ) The only time it was fairly useful was one winding hole where the prevailing wind blows the boat sideways towards moorings as soon as the boat reverses during the turn. Even then, anything much above a stiff breeze, and the bow thruster wasn't man enough for the job.

It broke a couple of years ago, and was never repaired. I, for one, don't miss it. 

[Top cat]

Thanks guys.  I'm not  convinced having one is a good idea but I have been told we are having one.  So I've decided on one that claims to be able to run for 7 minutes.   Of course that would completely  drain the battery so its self limiting. I'm thinking a 60 second timer with a 30 second reset should do it. Or maybe have a coin operated system, insert one old style pound coin for 1 minutes operation.:).

 

Top Cat

[mrsmelly]

3 minutes ago, Top cat said:

Thanks guys.  I'm not  convinced having one is a good idea but I have been told we are having one.  So I've decided on one that claims to be able to run for 7 minutes.   Of course that would completely  drain the battery so its self limiting. I'm thinking a 60 second timer with a 30 second reset should do it. Or maybe have a coin operated system, insert one old style pound coin for 1 minutes operation.:).

 

Top Cat

Your problem is of course the varied ability of the several drivers. The trip boat I skippered mainly was over a hundred tons 80 feet by just over 20 feet beam 2 decks 172 seater with ten crew and air draught of about 16 feet. One of the part time skippers used the thruster a fair bit but even then only to settle the boat sometimes in a lock. Myself and the other full time skipper would more than often do both our 3 hour cruises each day without ever using it. Bursts of even 30 seconds in my opinion should never be warranted by a competent boat handler on boats this small. I would never fit any bow thruster on any of my own boats, my last boat had one fitted from new and I bought it second hand but they are simply not needed if handler is competent. My present narrowboat is only 68 feet long so in no way big enough to warrant a thruster. Your hands of course are tied as its not your boat so I am sure you will make a good a job of it as you can.

[howardang]

22 hours ago, Mike the Boilerman said:

Its hard to imagine an 'emergency' that requires extended use of a bow thruster....

On the other hand... I know of some vessels which had omni-directional gill jet bow thrusts and one vessel's claim to fame was that she used it as her sole propulsion to sail home when both her propellers were fouled - a distance of a couple of hundred miles which took two days or so!

Hard to imagine the need on the cut, though.

 

Howard