mikesyam
Member
Just signed for a Azimut 55 and want to fit a stern thruster so need opinions on what size and make to go for please.
Thanks Mike
Thanks Mike
What Size And What Make Stern Thruster
- Thread starter mikesyam
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Nick_H
Active member
Mike
This isn't a macho "I could drive an aircraft carrier blindfolded" comment, but you really don't need one. With just a bit of practice you can make the back end of the boat do pretty much anything you want to with twin shafts, and to some extent it gets easier as the boat gets bigger. The Azi 55 has relatively low sides so shouldn't suffer too much with windage. Personally i'd spend money upgrading the bow thruster before I fitted a stern thruster.
However, if you do decide to fit one, then it may make sense to use the same manufacturer as the bow thruster?
Congratulations on signing up, hope the survey goes well and look forward to seeing the pictures soon. Where will you be keeping her?
aquatom
Member
I would recommend a sidepower SE120/215.
Not the cheapest but good quality.
If the thrusters is fitted in a way that it sticks out further than the bathing platform be sure to fit a metal cage to protect it from damage. I watched a boat sink last year in Mallorca where the bow line snapped and the boat hit the quay. The stern thrusters gearbox was pushed through the tube and let an a large amount of water very quickly.
If a seperate water tight compartment can be made even better.
Not the cheapest but good quality.
If the thrusters is fitted in a way that it sticks out further than the bathing platform be sure to fit a metal cage to protect it from damage. I watched a boat sink last year in Mallorca where the bow line snapped and the boat hit the quay. The stern thrusters gearbox was pushed through the tube and let an a large amount of water very quickly.
If a seperate water tight compartment can be made even better.
CMJ
Member
I agree with Nick_H's comments 100%. It's amazing how much control you can have at the stern with twin shafts and if it's anything like the AZ50, you'll have no worries. Also, AZI's seem to use underpowered bow thrusters, which again reinforces Nick_H's suggestion of upgrading that rather than installing a Stern Thruster.
Glad you chose the Azi BTW despite JFM's very generous offer of a full test day on his SQ58.
Glad you chose the Azi BTW despite JFM's very generous offer of a full test day on his SQ58.
jfm
Well-known member
Congrats on the deal
I'd agree with Nick and CMJ. Again, not a macho comment, but you wont need one. The stern will kick sideways as well with the props as with a thruster. Put port engine fwd, stb engine reverse, and b/t to port, and she will move sideways to port like on IPS
But if you do decide to get one, sleipner seems a top make and I've never had problem with 2 of them in 6 years. Osmotech deal in them and seem a very good firm. You want about 8hp. Generally the stern needs about 75% of the bow, and the correct bow rating is 11hp (going by my Sq58, whose 11hp bow thruster seems the right size). Dont be fooled by suppliers who quote kgf thrust (including the princess website). The effectiveness of the thruster is a function of its power, which is thrust x the flow rate or some other item with a "per time unit" in its dimensions. Basic laws of physics. Anyone who quotes just thrust is either not understanding or perhaps hiding the fact it hasn't got any power
I'd be quite scared of one with kids swimming all day in the med. The thought of kid A fiddling with it, or a girl getting long hair near it, while kid B wonders "what is this grey stick for?" doesn't bear thinking about. Make sure to fit isolator switches left right and centre and don't rely on the double-on button which can't be 100% kid-proof. Just imho
An 8hp will draw 250amps at 24v so check if your batteries can do both bow (300amps?) and stern together, or fit more batteries (eek)
kcrane
Active member
"You don't need one" has a silent letter, which spells "if you are confident and experienced".
I was told the same thing. They're right that they don't need one. So I immediately had Mike Ingram at Osmotech fit a matched sternthruster to an upgraded bowthruster (Sleipner).
In fact, as jfm, Nick_H and others say, I've found that I can indeed move the stern sideways with the engines, but always with some back and forward moment. If you imagine that your throttle controls are in a V shape, rather than parallel, I find that helps me 'see' which way the stern will go.
However, with 1200hp and a relatively light boat, even a tiny burst of power moves the boat significantly. With the two thusters I can tweak its attititude more gently. I have found that I like the way the boat spins on the spot by pushing sternthruster one way, bow the other. It isn't as laboured as using the engines (but it is noiser).
Last weekend I was on a pontoon at Cowes. When I came back I had a yacht either side of me, 3ft-6ft away at bow and stern (they like the 'capture the mobo' game). I slid out sideways (perfectly parallel) with no more than a slight push to one side on two small levers, delightful. No springs, no drama - heck of a lot of boiling water and noisy thrusters tho - but only for 5 secs.
It will cost you single figure £k's and in the overall cost of an Azi 55 it is small beer, for the peace of mind should you need it, worth every penny.
I was told the same thing. They're right that they don't need one. So I immediately had Mike Ingram at Osmotech fit a matched sternthruster to an upgraded bowthruster (Sleipner).
In fact, as jfm, Nick_H and others say, I've found that I can indeed move the stern sideways with the engines, but always with some back and forward moment. If you imagine that your throttle controls are in a V shape, rather than parallel, I find that helps me 'see' which way the stern will go.
However, with 1200hp and a relatively light boat, even a tiny burst of power moves the boat significantly. With the two thusters I can tweak its attititude more gently. I have found that I like the way the boat spins on the spot by pushing sternthruster one way, bow the other. It isn't as laboured as using the engines (but it is noiser).
Last weekend I was on a pontoon at Cowes. When I came back I had a yacht either side of me, 3ft-6ft away at bow and stern (they like the 'capture the mobo' game). I slid out sideways (perfectly parallel) with no more than a slight push to one side on two small levers, delightful. No springs, no drama - heck of a lot of boiling water and noisy thrusters tho - but only for 5 secs.
It will cost you single figure £k's and in the overall cost of an Azi 55 it is small beer, for the peace of mind should you need it, worth every penny.
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MapisM
Well-known member
Seconded 100%.
And btw, I'd rather have an hydraulic b/t than any electric ones - though I'm afraid that this is a helluva upgrade on a boat which doesn't have any other hydraulic system, requiring an engine pto, hydraulic pump, hoses, ...
But as a matter of fact, the twin screws alone are good enough to cope with most situations with no thruster at all - just ask hlb!
If and when you really NEED a b/t, it's an hydraulic one you want to have, on a 50'+ boat.
hlb
RIP
It's been agreed on here since the begining of the forum, no need for stern thrusters, particularly with twin shafts. I've never found a use for a bow thruster, but can except, that backing onto stern to mooring on the Med, a bow thruster is helpfull. The problem then being, that once a bit in, you cant move the arse about, cos no room.
The main problem is, folk are trying to drive cars, not boats. Watch a little ferry man, he has neither bow or stern thrusters, only one engine, yet parks up first time every time.
There seems to be loads of money in teaching folk to do things wrongly, there for increasing the need for bow/stern thrusters. Then the man that can. Less you have four arms, it's just a dam sight more difficult.
The main problem is, folk are trying to drive cars, not boats. Watch a little ferry man, he has neither bow or stern thrusters, only one engine, yet parks up first time every time.
There seems to be loads of money in teaching folk to do things wrongly, there for increasing the need for bow/stern thrusters. Then the man that can. Less you have four arms, it's just a dam sight more difficult.
grumpy_o_g
Well-known member
There's a joystick thingie for shaft drives now apparently - couple of videos on youtube if you google for ZF Joystick System.
http://www.zf.com/corporate/en/comp...uvering_system/Vericor_Propulsion_System.html
http://www.zf.com/corporate/en/comp...uvering_system/Vericor_Propulsion_System.html
Piers
Well-known member
Just had a stern thruster fitted to Play d'eau. Same make - Sidepower (Sleipner).
The advice I got was spot on.
First, upgrade the bow thruster props to the new style which would add 15kgs thrust (You probably won't need this if the boat is new).
Second, fit a lesser power stern thruster. This is because it takes more power to move the bow than ther stern. So if you were to use both together the boat will come off parallel to the pontoon rather than than the stern running out leaving the bow behind.
I followed the advice and it works a treat. If you want the name and number of the advisor, do send a PM.
The advice I got was spot on.
First, upgrade the bow thruster props to the new style which would add 15kgs thrust (You probably won't need this if the boat is new).
Second, fit a lesser power stern thruster. This is because it takes more power to move the bow than ther stern. So if you were to use both together the boat will come off parallel to the pontoon rather than than the stern running out leaving the bow behind.
I followed the advice and it works a treat. If you want the name and number of the advisor, do send a PM.
AndieMac
Well-known member
The ferry man also operates his boat all day, everyday, so that it becomes an extention of himself, so to speak.
If you can afford the thrusters, even if you don't use them, they can be a form of morale booster, or a 'just in case' for that difficult berthing moment.
CMJ
Member
This doesn't apply to me as I'm definitely not experienced but more like a novice having been boating for only three years.
Because of this lack of experience, I've wanted to learn on a boat that would allow me to transfer my skills onto something else if need be and if I become accustomed to a sternthruster, I fear it might feel like I'm missing an arm or something if I jump onto someone else's boat that doesn't have one.
There have been times in the past where I wished I'd had one but the consequence of not having one has forced me to begin to learn how to handle the boat with just with the shafts, and occasional use of the bow thruster.
None of this guarantees that I won't c#ck it up massively at some point and wish I had a stern thruster!
Hurricane
Well-known member
I'm going to dissagree with most of the experts on here.
I very rarely use my stern thruster but its always good to have it as a standby.
My thoughts are that you probably dont use your boat that often so could get yourself into a tricky situation. I this case, the cost of a stern thruster could save its cost in damage each year.
Here's another thought.
You have arrived at your berth using engines as mentioned above - ours is alongside a finger - and the wind is blowing you off. You really dont want to keep fiddling with the main engines (2400hp in our case) just to keep the stern in whilst the crew (SWMBO) ties off - in our case, we are often just the two of us and she (SWMBO) cant be in two places at the same time. This is where the little radio remotes come in handy. I actually pop down and help whilst still operating the thrusters. In our case (and with your new boat) its probably too heavy to pull in (manually) sideways anyway.
Dont listen to those above - Stern Thrusters are very useful - especially in a tight situation.
Do yourself a favour - fit one - and save money in the long run.
Sorry guys - if you've never had them you probably have never missed them.
So, I duck and run for cover but at least my two year old boat hasn't a single scratch.
I very rarely use my stern thruster but its always good to have it as a standby.
My thoughts are that you probably dont use your boat that often so could get yourself into a tricky situation. I this case, the cost of a stern thruster could save its cost in damage each year.
Here's another thought.
You have arrived at your berth using engines as mentioned above - ours is alongside a finger - and the wind is blowing you off. You really dont want to keep fiddling with the main engines (2400hp in our case) just to keep the stern in whilst the crew (SWMBO) ties off - in our case, we are often just the two of us and she (SWMBO) cant be in two places at the same time. This is where the little radio remotes come in handy. I actually pop down and help whilst still operating the thrusters. In our case (and with your new boat) its probably too heavy to pull in (manually) sideways anyway.
Dont listen to those above - Stern Thrusters are very useful - especially in a tight situation.
Do yourself a favour - fit one - and save money in the long run.
Sorry guys - if you've never had them you probably have never missed them.
So, I duck and run for cover but at least my two year old boat hasn't a single scratch.
Nick_H
Active member
Hey, that's the beauty of the forum, you get different opinions to help you make your own judgement. HLB thinks you don't really need a bowthruster, i'd reccommend one every time, same thing really, just different opinions.
Mikesyam - if the Azi has a Sleipner bowthruster, get yourself a spare flexible coupling, as they can (purposefully) fail if something jams in the bowthruster, and they are easy to change. edit: just remembered it's called a Lovejoy S-Flex coupling, and my Sidepower 125T takes a no.4 I think, but best to check first.
Mikesyam - if the Azi has a Sleipner bowthruster, get yourself a spare flexible coupling, as they can (purposefully) fail if something jams in the bowthruster, and they are easy to change. edit: just remembered it's called a Lovejoy S-Flex coupling, and my Sidepower 125T takes a no.4 I think, but best to check first.
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MapisM
Well-known member
Mmm... I see what you mean, but I honestly believe that no thrusters, IPS, Zeus, whatever can actually per se save any damage costs.
What can and does save damage costs is the helmsman awareness of what he can or can't expect from his boat - regardless of how she's equipped.
Actually, in this respect I'd dare saying that I've seen "macho" approaches mostly in boats with plenty of these tools.
Present company excepted of course, but as a matter of fact the only scratch in my ten years old boat (with no thrusters at all) came courtesy of a Pershing 64 with all the bells and whistles you can think of.
Mooring stern to on my port side, in a reasonably wide berth (a couple of feet each sides, maybe more), in a glorious sunny day with no wind and current at all.
Standing in the cockpit with a remote gizmo in his hand, this gentleman reversed diagonally in his slot, pretending to straighten the boat just with the bow and stern thrusters. But as it happened, he kept the arnesons hard over to stbd, and each touch on the throttle to keep the boat reversing was more than enough to counteract the thrusters effect.
The guy finally decided to repeat the maneuver after not so gently touching my bow with his swim platform.
I was not impressed also when he waved a sort of excuse at myself and swmbo, astonishingly looking at him from our f/b in religious silence...
hlb
RIP
MapisM
Well-known member
I forgot to mention.
When all is said and done, back to your original question: I'd recommend to have a look also at Wesmar products.
I can't speak for Sleipner, but I've seen how Wesmar thrusters are built and can't imagine how they could get any better.
When all is said and done, back to your original question: I'd recommend to have a look also at Wesmar products.
I can't speak for Sleipner, but I've seen how Wesmar thrusters are built and can't imagine how they could get any better.
AndieMac
Well-known member
Seconded 100%.
And btw, I'd rather have an hydraulic b/t than any electric ones - though I'm afraid that this is a helluva upgrade on a boat which doesn't have any other hydraulic system, requiring an engine pto, hydraulic pump, hoses, ...
But as a matter of fact, the twin screws alone are good enough to cope with most situations with no thruster at all - just ask hlb!
If and when you really NEED a b/t, it's an hydraulic one you want to have, on a 50'+ boat.
This post reminds of an experience with a very heavy displacement boat, with massive windage, I was relocating to a fuel berth, in a hard running cross tide and wind situation.
The pto ran off the stb engine, but needed quite considerable revs to operate (build enough oil pressure) to run the hyd. bow thruster.
The boat had morse controls on twin screw, so as the boat was making its final approaches (nearly stationary) to the pontoon (being pushed off the berth), a descision had to be made whether to use the stb. engine to either run the pto, (high revs) or use it to walk sideways, one against the other. Just one of those moments!
Of course I did guess at the time this arrangement (hyd. thruster) was basically down to a poor installation/set up on this vessel, and not typical of this type of machinery. As MM says, they are highly regarded.
rubberduck
Well-known member
Totally agree, we only have a 41 ft sports cruiser & our stern thruster is just great at holding the boat steady while tying up. Also got me out of trouble a couple of weeks back when I underestimated the wind cos it was a nice sunny day & just tried to bring her straight back in.
AustinPowers
New member
It saddens me that anyone who could own a 55' twin screw yacht could find it hard to handle a boat on both motors alone without having to resort to a stern, or for that matter, bow thruster.
A quick boat handling course or even an ICC Power would sort that out and give the helmsman an infinitely finer experience when out on his boat. Its amazing what you can do with the slightest input from one engine and a pre-selected helm. The most important thing they teach you is think ahead and only ever use slight movements of the throttles, nothing rushed. If you aren't going fast enough to do any damage, you can always fend off if it all goes wrong. Just keep inputs to the minimum and only blip the throttles, even an Azimut 55 shouldn't need any more than a tickle of power, in the right direction.
Maybe this is the reason why so many of the larger boats just sit on their pontoon like an Olympic flame, never going out.
