Bowthruster Question...

[Aardee]

As an ignorant Raggie, I have a question.

If we have the technology to make whisper quiet 400HP diesels, why does even the smallest bowthruster sound like a socket set being thrown down the stairs??

The 'orrible noise is really all I have against them...

Graham.

<hr width=100% size=1>"I am a bear of very little brain and long words bother me" - A A Milne.

 

[muchy_]

When I first heard someone use their bowthruster I was diving for cover, convinced it was gonna blow. /forums/images/icons/smile.gif

<hr width=100% size=1>Is it the weekend yet?

 

[adarcy]

Although I'm not an engineer of any sort so believe it at your peril

I have seen written frequently that the noise is turbulence in the tunnel. They are pretty thin things and prob would resonate. Also, props are fairly simple blades so they can work equally well in either direction so they probably would set up anything but a smooth quiet laminar flow

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[Aardee]

Maybe it's a "look what I got from Santa..." thing /forums/images/icons/wink.gif ??

<hr width=100% size=1>"I am a bear of very little brain and long words bother me" - A A Milne.

 

[TrueBlue]

Possibly rather cheap straight cut gears instead of angled or helical (as used in your car)?

My opinion is probably rubbish.

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Stop what you're doing and wait my signal

 

[boatone]

I think the word you are looking for is 'cavitation'. They are simple propellor devices and waterflow is restricted by the tunnel which is usually a) quite thin walled and b) usually completely un-insulated. The result is lots of noise which is amplified by the undamped structure around it - even more so on a steel boat like mine..

There seems to be divided opinion as to whether its a 'good' thing (Hey guys..Ive got a BT !!) or a 'bad' thing...(that prats showing off cos he's got a BT !!).

The noise is the only thing I dont like about mine...brilliant addition to the boat handling armoury.

I'm sure hlb will arrive here shortly.........

<hr width=100% size=1><A target="_blank" HREF=http://www.boatsontheweb.com/> Website, Photo Gallery, Chat Room, Burgees</A>

 

[hlb]

Or. Look at me. I'm the prat with a bow thruster..../forums/images/icons/laugh.gif Gulp!!

<hr width=100% size=1> Flags Solly MFBR</font color=red>
Haydn

 

[Lilteenskiperjo]

huho, ur askin for trouble there!

<hr width=100% size=1>Spirt de la mer ! ;-)

 

[adarcy]

<<'cavitation'>>

Yes thank you smarta....

No I'm sorry. I did preface it I'm no engineer.

<<brilliant addition to the boat handling armoury>>

when hlb sees that we'll have nearly as many rows that grind on as the raggies do about ColRegs and ensigns

Hadn't seen him while I was posting (slowly) .... but I did warn you
<hr width=100% size=1><P ID="edit"><FONT SIZE=-1>Edited by adarcy on 18/08/2004 18:17 (server time).</FONT></P>

 

[boatone]

Right...thats it.......

.....in the last 24 hours I have been called a puff by hlb, an oldgit by alistairr and now a smarta.. by you.......
There is a limit you know......I am off to see matron.......

<hr width=100% size=1><A target="_blank" HREF=http://www.boatsontheweb.com/> Website, Photo Gallery, Chat Room, Burgees</A>

 

[Ifraser]

The noisy bow thruster question is one that had puzzled me for years....even the poshest boats seem to make a horrible noise....
As for whether they are a good thing....I drive an aquastar 38 at work, 14 tonnes and haven't really missed a bow thruster but having driven a few lighter planing pleasure boats I can see how they are useful particularly for people who are not blessed with being able to go to sea every day so cannot build up the experience. I do hate to see them overused and in Poole harbour the other day, upper wych channel a man was shouting for poeple to get out of the way as his bow thruster had broken down....he had twin engines and i guess definately needs more practise!! I used to be dead anti bow thruster but as someone else posted they can be a useful addition to the armoury particularly if your boat is light on the nose.
Boating is for fun so each to his / her own but don't use your thruster to steer your boat in a quiet anchorage!!!


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[steverow]

The noise is a combination of, motor, cavitation, and less than average gear train on all but the most expensive models.
Couple this with a "square sided prop" on most models, gives you the unpleasant grunting noise that most of them emit.

But hey...it's another aid to close quarters steering and there's nothing wrong with having one. If's it's available ...use it.!!

I wouldnt be without mine, with two locks to go through to get to sea. Money very well spent.!!

Steve.


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