SteveE
New member
Nice looking boat... but the stern thruster looks like an eletric whisk... I would say from the look of the stern it needs to be larger than that.....
Improving a stern thruster
- Thread starter TerrifiedTony
- Start date
PaulGooch
Active member
Can't see any way cowls would help. The poofster is as low as it can get and angling the thrust down isn't going to make any difference.
hlb
RIP
Could you not put some row locks across the stern and use them like a sort of side ways on Viking ship.
TerrifiedTony
New member
Eeeh Mr HLB, well I laffed, that was gradely...I really can't compete with either your helmsmanship or your witty repartee. So I will leave you with a final thought..
Lawn Tractors are usually red unless it a John Deere in which case they are green and yellow. Hope this helps you to notice the difference in future.
And one final, final thought is that my surprise Xmas present this year is a remote control for the bow/stern thrusters. I will wear this on a lanyard and control them both from the bathing platform. My ambition is that for my birthday I will also get one for the "fly by wire" electronic throttle. This way I can stay safe on the pontoon and send Lazy Dreamer off for a short trip, a bit like the boating lake at Southport.
I may send her upto Wales to show you how boat handling should be done but there again I wouldn't want to upset you to show how easy it is with the right equipment. i.e two engines or a few electronic gizmos.
Lawn Tractors are usually red unless it a John Deere in which case they are green and yellow. Hope this helps you to notice the difference in future.
And one final, final thought is that my surprise Xmas present this year is a remote control for the bow/stern thrusters. I will wear this on a lanyard and control them both from the bathing platform. My ambition is that for my birthday I will also get one for the "fly by wire" electronic throttle. This way I can stay safe on the pontoon and send Lazy Dreamer off for a short trip, a bit like the boating lake at Southport.
I may send her upto Wales to show you how boat handling should be done but there again I wouldn't want to upset you to show how easy it is with the right equipment. i.e two engines or a few electronic gizmos.
D
Deleted User YDKXO
Guest
TT, until I got my present boat, I was with Haydn on the subject of sternthrusters but having had a season with my boat fitted with a sternthruster, I've changed my mind. Maybe I'm just going soft in my old age.
There are 2 things which make a sterthruster useful IMHO. First the action of a sternthruster is much softer than using the engines, particularly on a twin engined boat. On my boat, the props seem to have a big bite on the water and engaging gear, even momentarily, causes a big movement. Sometimes you only want a small gentle movement of the stern and thats when I find the sternthruster useful. Second, the pivot point of the props and the sternthruster are different. When you use the engines on a twin engined boat to turn the stern away from a quay or pontoon, you are also turning the bow onto the quay or pontoon because the pivot point is around 1/3rd of the boat length aft of the bow, so you need plenty of fenders at the bow. On the other hand, a sternthruster pivots the stern of the boat about the bow so you are not forcing the bow against the quay when you use it, hence less fenders needed.
In the case of your boat, the sternthruster looks big enough to me but I'm no expert and even though you've got a fairly flat bottomed boat, the thruster seems to be reasonably well immersed. Dont forget that a sternthruster can never work as fast as a bow thruster. There is very little hull in the water at the bow and it is relatively easy to move the bow on most boats. At the stern, there's a lot more hull immersed in the water plus the thruster has to overcome the resistance of the rudders, props, shafts etc; you can't expect a sternthruster to move the stern as easily as a bow thruster moves the bow. All the same, it has to be worth investigating whether your sternthruster can be improved in some way, maybe fitting the cowlings you refer to, a double prop arrangement (its not clear whether your sternthruster is double or sigle prop), changing the prop type, increasing the motor power or worst case, fitting a larger thruster. Talk to Westwood or the thruster manufacturer. I've found Osmotech to be very helpful in the past http://www.osmotech.co.uk/thrusters-and-systems You will also see on this link a pic of a sternthruster with the cowlings that you describe. It must be worth talking to them to find out about this feature even if you dont have a Sidepower thruster
jfm
Well-known member
I'm no fan of stern thrusters (though my new boat has one; they kinda insisted...!) but I agree with Deleted User that the one in that pics looks the right size to me. Not that looking at it really counts; what matters is the hp of the motor and the pitch of the prop.
Unless it is ventilating (ie mounted too near the surface) putting ears on it will not change the thrust, despite many advisers telling you it will. The thrust is newtonian and occurs at the propeller faces and nowhere else. You can alter the directon of the thrust with ears, but I can't see the point of that. My new sternthruster has ears but that is to stop the wash from it slopping up thru the swim platform, not to increase its thrust
Unless it is ventilating (ie mounted too near the surface) putting ears on it will not change the thrust, despite many advisers telling you it will. The thrust is newtonian and occurs at the propeller faces and nowhere else. You can alter the directon of the thrust with ears, but I can't see the point of that. My new sternthruster has ears but that is to stop the wash from it slopping up thru the swim platform, not to increase its thrust
hlb
RIP
Lawn Tractors are usually red unless it a John Deere in which case they are green and yellow. Hope this helps you to notice the difference in future.
We used to have a grey Westwood, but yes and I for the first time will agree with you, most are now, most definitely red.
One of my red tractors. (the big one)
I think your problem is Mr Teriffied. Of all the folk you could have picked on, is me in my hospital bed. You have given me hours of entertainment and I hope I have not offended you to much.
I still take nothing away from what I said though. You have 65 HP at your disposal, and your trying to solve your problem with an egg whisk.
We used to have a grey Westwood, but yes and I for the first time will agree with you, most are now, most definitely red.
One of my red tractors. (the big one)
I think your problem is Mr Teriffied. Of all the folk you could have picked on, is me in my hospital bed. You have given me hours of entertainment and I hope I have not offended you to much.
I still take nothing away from what I said though. You have 65 HP at your disposal, and your trying to solve your problem with an egg whisk.
D
Deleted User YDKXO
Guest
jfm, did you find a solution to the safety aspect of sternthrusters with swimmers about? I remember you posting on the subject a while back. I was in the water scraping cling-ons off my props this summer when a numpty teenager on the flybridge decided it would be a good idea to put his feet up on the helm and accidentally pushed the sternthruster joystick. It scared the bejasus out of me
Hurricane
Well-known member
I know most aren't but my thrusters are interlocked through the engine isolator.
I often go down underneath but wouldn't dream of it with the engine/thruster isolator on.
jfm
Well-known member
Yikes! No I haven't dealt with it yet, but will do when I take delivery. Mine are hydrualic so at anchor they will only work if a genset is running, which of course one will be a fair bit. Although the motors are hydraulic, the valve controls are electric so I am hoping there are enough isolator switches but if not I will just add a key switch
On yours you must have a 250Amp breaker for the s/thruster, operated remote control-ly by a solenoid on the breaker, right? In which case you can just use the remote control circuit to isolate the power to the st thruster, and use a key switch or hidden switch so no-one can turn it on except you
D
Deleted User YDKXO
Guest
Well, yeah, I can always switch the breaker off at the electrical control board or just switch each individual control station off but thats assuming I remember to do it and then remember to turn it on again, which, knowing me, I wont. I suppose the best solution would be to wire the thruster circuits such that they were only live when the engine ignition circuit is on
I was thinking more of some kind of safety grille over the thruster tunnel ends but I dont know how much this would effect the thruster performance. Does anyone know of a person getting tangled up in a thruster mechanism and what sort of damage that person suffered? I'm also wondering what force it would take to break the shear pin on the drive shaft and whether that in itself is a safety mechanism?
D
Deleted User YDKXO
Guest
Hurricane, does that mean that the thrusters are de-energised when the engine battery isolator switch is turned off?
Hurricane
Well-known member
Yes but I know that Sealine (for example) usually have separate isolators.
jfm
Well-known member
Problem with grilles is that girls' hair can still go in. The shearpin is dependent on thruster size obviously, and I'm heading for a 20hp, but even with say 5hp I wouldn't fancy a tug of war between a shearpin and a scalp
hlb
RIP
All this thrutching about sounds far to complicated and difficult for me. I'll stick with the two hands on the big levers approch.
Croozer
New member
I am also a stern thruster fan.
Agree that it is not entirely necessary but adds that final touch getting stern line on.
Thing is it is possible to use throttles, one forward, one reverse etc but my Phantom 46 would always creap forward requiring a bit more juggling.
Agree that it is not entirely necessary but adds that final touch getting stern line on.
Thing is it is possible to use throttles, one forward, one reverse etc but my Phantom 46 would always creap forward requiring a bit more juggling.
Renegade_Master
New member
two hands Haydn yer big poof, I only use one
Ubergeekian
New member
A propeller near the surface generally develops less thrust than an immersed one because it is easier to make waves than to push water sideways. If some ducting arrangement can reduce wavemaking then it may well increase the thrust (at the propeller blades, as you say).
yankee1
Member
Stern thrusters
The only sensible conclusion to this debate is to eliminate both of the really expensive oily bits and just have thrusters. Then you could wiggle your way forward and backward at a much lower cost, of course assuming we had hlb's maneuvering skills, and also move sideways when needed. All these newfangled propulsion devices...takes all the fun out of docking safely!
The only sensible conclusion to this debate is to eliminate both of the really expensive oily bits and just have thrusters. Then you could wiggle your way forward and backward at a much lower cost, of course assuming we had hlb's maneuvering skills, and also move sideways when needed. All these newfangled propulsion devices...takes all the fun out of docking safely!
hlb
RIP
Now that really could be fun, we could have contests to the tune of the Viennese Waltz. With Anne widdicombe as the ringer.
There would be line dancing of course and the Salsa. I might even be able to train M Farter as a Pole Dancer, which would be an interesting exercise.
Maybe Terrified Tony should stick to the Hokey Cokey.
You stick yer righ bum out.
Yer right bum in.
Yer right bum out
In out in out.
And you shake it all about.
You do the Hokey Cokey
And you turn around.
Thats what it's all about.
Hey.
Oh Hokey Cokey Cokey
Oh Hokey Cokey Cokey.
.............................
anyone know the rest of the words.
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