Hydraulic thrusters / bow and stern

[Deleted User YDKXO]

Yep, exactly what I thought to be the logic on every boat I've seen with hyd PTO(s) plus separate pump for STAR usage.
I was unsure about the need for separate returns though, and I thought Deleted User might have had reasons to mention them...

Well it was you that decided to drift the thread to include the subject of hyd stabs when the thread was only about hyd thrusters. Of course, if you have a number of different hyd feed requirements for thrusters and stabs, then it doesn't make sense to have an independent circuit with an independent pump for each function. Going back to my original point, I would still maintain that 2 simple independently driven hyd thrusters as Horizon seems to fit is better than the 2 electric thrusters (or 1) that most builders fit so they deserve some credit at least for that, whatever the apparent shortcomings of the system

 

[MapisM]

I would still maintain that 2 simple independently driven hyd thrusters as Horizon seems to fit is better than the 2 electric thrusters (or 1) that most builders fit so they deserve some credit at least for that, whatever the apparent shortcomings of the system

Sorry, but I'm afraid I can't give them any credit for using a better equipment and installing it the wrong way.
Though that's just MHO, of course.

 

[Deleted User YDKXO]

Mmm... I struggle to see how a manifold could add any meaningful costs to a setup with two PTO hyd pumps and two hyd thrusters.
It would have been a different story if, as you said, the two pumps couldn't work in parallel for some reason, but if they do in M2 there's no reason why they couldn't on any other boat.
All considered, it just sounds like a nonsense plumbing choice from Horizon, imho...

Yeah whatever you say but its not just a manifold but electro valves and control system as well. With due respect to jfm, I assume that M2 was not built to a budget which most production builders have to follow. Of course there is always the chance that the broker was wrong

 

[P4Paul]

Sorry, but I'm afraid I can't give them any credit for using a better equipment and installing it the wrong way.
Though that's just MHO, of course.

I think it is more a case of them not being fitted the wrong way, just not your preferred way. I would hazard a guess that everyone is right, the broker made the comment that each pump took control over one of the thruster motors. You (and I) would want dual circuit control but I wouldn't be at all surprised to find out that each pump was the priority feed to a single motor while also being the makeup pump for the other. Both engines running, full power to both thrusters - one engine running, partial power to both.

Without knowing if it is plumbed open or closed circuit and with or without proportional control it is all complete speculation on how it works and is plumbed to be honest.

 

[Piers]

We have a hydraulic pump on each engine for the stabilisers. Either can drive the stabs in case of engine failure as separate pumps, controlled by a switch in the Pilot house. I wanted this arrangement in case an engine failed and we needed the other to drive the stabs.

To keep an even balance of usage, we use No 1 when running north, and No 2 when running south.

Stabs are Trac.

 

[MapisM]

You (and I) would want dual circuit control but I wouldn't be at all surprised to find out that each pump was the priority feed to a single motor while also being the makeup pump for the other. Both engines running, full power to both thrusters - one engine running, partial power to both.

Agreed, it would be neither the first nor the last time a broker doesn't know the exact specs of what he's selling, though as I understood this guy deals mostly (exclusively?) with Horizons, so you'd expect him to know his stuff.
Just curious, by "priority" vs. "makeup", do you mean pumps selectable by the helmsman, through a Y-valve or something, as Piers mentioned?
I'm asking because I've also seen boats where both PTO pumps are always feeding in parallel the whole hyd system, without the need to select either one or the other.
If one engine doesn't run (and/or one PTO pump fails), all hyd systems just continue to work without the need to do anything - though the available power is obviously lower.
Not sure if that's also the case with M2. Maybe yes, considering that jfm confirmed that the two pumps run in parallel?

 

[jfm]

I'm asking because I've also seen boats where both PTO pumps are always feeding in parallel the whole hyd system, without the need to select either one or the other.
If one engine doesn't run (and/or one PTO pump fails), all hyd systems just continue to work without the need to do anything - though the available power is obviously lower.
Not sure if that's also the case with M2. Maybe yes, considering that jfm confirmed that the two pumps run in parallel?

Yes that's how mine is set up MapisM. I cannot see the point in manually selecting one PTO versus the other. Also there is not point "resting" them: these things have a life way in excess of the hours they will ever see on a pleasure boat and if one were to fail it is just a credit card catalogue item

BTW Deleted User, hydraulic bow+ stern thruster install is standard spec on Sq78. The only upgrades I have are the stabs, and proportional control valves so I can throttle the bow and stern thrusters

 

[SEARANGER ANCASTER]

Sorry to jump in with an advert , but hydraulics are my business so happy to give an advice and/or supply pumps and clutches to suit.

 

[Bilgediver]

What the pros and cons of these when compared to standard electric versions that are normally supplied by main stream builders of boats please?

How do you intend to power the hydraulic thrusters? I was surprised on one boat I was on how much power the thrusters absorbed from the propulsion engine which also needed to be running at a decent speed to operate the thrusters when used in anger.

 

[SEARANGER ANCASTER]

How do you intend to power the hydraulic thrusters? I was surprised on one boat I was on how much power the thrusters absorbed from the propulsion engine which also needed to be running at a decent speed to operate the thrusters when used in anger.

We normally go for a clutch so you just engage the pump when coming into harbour/marina . That way there is no draw on the engine when cruising normally. If its set up with the correct size of pump to suit the thruster motor , there should be no reason for the engine to be screaming and it should be fine on tickover.

The advantages over electric are the torque compared with physical size and that they can run for much longer periods. Disadvantages being the cost and the fact you need an oil reservoir somewhere but it doesnt necessarily need to be that big.

 

[Deleted User YDKXO]

Agreed, it would be neither the first nor the last time a broker doesn't know the exact specs of what he's selling

I believe he's Italian so you could be right

 

[Deleted User YDKXO]

BTW Deleted User, hydraulic bow+ stern thruster install is standard spec on Sq78.

How are they set up if you don't spec stabs?

 

[jfm]

How are they set up if you don't spec stabs?

With a PTO on each engine, parallel plumbed, so either engine can operate both thrusters and the windlass, and normally both engines are operating both thrusters and the windlass via a common pressure manifold. The standard spec is open/shut valves to both thrusters ie not proportional valves. Also there are manual lever valves in the engine room so you can operate the thrusters and winch if you lose your electrics.

I don't know if the standard spec has an oil cooler; mine does, with a tube stack heat exchanger and a centrifugal pump powered by a hydraulic motor to circulate the seawater

The spec on M2 is bigger all round because it has to run stabs too, and every box is ticked. There is a bigger tank; oil cooling via hydraulic motor/centrifugal seawater pump; sight gauge as well as electronic level metering on the tank; manual override levers on all hydraulic valves; restriction gauges on both the oil the filters; proportional thruster valves with "throttle lever" proportional joysticks and "hold" function that your Horizon dealer likes ; 10hp 3phase Rexroth electro hydraulic pump via VFD; logic control ie when thrusters are used stabs are turned off; touch screen control and diagnostics at lower helm with all parameters displayed like oil temp, oil pressure, hours run, electric pump on/off, etc; waterproof smaller non touch screen repeater on flybridge helm

Also Fairline will integrate the hydraulics by using one pack to run also the passerelle and the updown platform. I de specced this and have independent small hydraulic packs for each of the passerelle and the up/down platform, for redundancy/simplicity reasons

 

[Deleted User YDKXO]

With a PTO on each engine, parallel plumbed, so either engine can operate both thrusters and the windlass, and normally both engines are operating both thrusters and the windlass via a common pressure manifold. The standard spec is open/shut valves to both thrusters ie not proportional valves. Also there are manual lever valves in the engine room so you can operate the thrusters and winch if you lose your electrics.

OK that's a reasonable spec

The spec on M2 is bigger all round because it has to run stabs too, and every box is ticked. There is a bigger tank; oil cooling via hydraulic motor/centrifugal seawater pump; sight gauge as well as electronic level metering on the tank; manual override levers on all hydraulic valves; restriction gauges on both the oil the filters; proportional thruster valves with "throttle lever" proportional joysticks and "hold" function that your Horizon dealer likes ; 10hp 3phase Rexroth electro hydraulic pump via VFD; logic control ie when thrusters are used stabs are turned off; touch screen control and diagnostics at lower helm with all parameters displayed like oil temp, oil pressure, hours run, electric pump on/off, etc; waterproof smaller non touch screen repeater on flybridge helm

Very nice spec indeed. Just to clarify, the Rexroth pump is driven by a 220V motor powered by a gennie which operates the STAR system when the engines are stopped? If the engines are running, the PTOs are driving their own pumps and the Rexroth is stopped? Or is that wrong?

 

[MapisM]

I believe he's Italian so you could be right

Oi, it was P4Paul the first who smelled a rat. We Italians aren't much better than anyone else at inventing BS, you know...
It's in the argument manipulation that we stand out.
After all, regardless of whether he knew all the technicalities or not, that broker managed to convince you that the Horizon is superior.
Which is what really matters from his viewpoint, innit?

 

[MapisM]

Just to clarify, the Rexroth pump is driven by a 220V motor powered by a gennie which operates the STAR system when the engines are stopped? If the engines are running, the PTOs are driving their own pumps and the Rexroth is stopped? Or is that wrong?

I can answer that: yep, correct.
The electric pump (which btw is 3-phase, hence requiring a VFD device unless you have a 3-phase genset, but that's a detail) works only at rest, and it can drive the whole lot (STAR stabs, winches, thrusters - though possibly not all together and surely not all together at full power).
Under way, I don't think there's any logical restriction to keeping the genset and this pump running, but it's pointless when the engine(s) PTO pump(s) are running.

 

[MapisM]

don't know if the standard spec has an oil cooler; mine does, with a tube stack heat exchanger and a centrifugal pump powered by a hydraulic motor to circulate the seawater

I would think - but just as an educated guess - that the cooler is required by the stabs.
On one hand, the stabs are the only thing that you realistically need to keep running continuously: even if having no restriction on running time is one of the pros of hyd thrusters, realistically nobody would keep them running for hours. Horizon show off-er being a possible exception...
And OTOH, even my archaic Naiad stabs have a heat exchanger, fed through the raw water intake of one of the engines.

Overall, M2 setup sounds indeed impressive, anyway.
Just curious, since you mentioned the passerelle and platform but not the crane: that is also on separate hyd pack, I suppose?

 

[Deleted User YDKXO]

After all, regardless of whether he knew all the technicalities or not, that broker managed to convince you that the Horizon is superior.
Which is what really matters from his viewpoint, innit?

Nah, I have owned far too many boats to be 'convinced' by brokers. Yes, I was impressed overall by the engineering on the Horizon and that includes the hydraulic thrusters, even if they are only independent, because I don't know of any other builder that fits hyd thrusters as standard in their 64footer. And there was a lot else to like about the mechanical specification of the boat too. However, there were a number of things I didn't like about the boat and I was not 'convinced' on those and that is the reason that I didn't buy the boat because there was certainly a good offer on the table. One thing I have learnt is that different builders have different strengths and weaknesses and no one builder can justly say that they are superior at everything

 

[MapisM]

I don't know of any other builder that fits hyd thrusters as standard in their 64footer.

TBH, coming to think of it, neither do I.
But don't dismiss electric thrusters just because "hyd is better".
On one hand, 60/70 feet is a borderline size, where there are good reasons for sticking to 24V rather than going through the complexity of hyd systems.
And otoh, there are also AC thrusters, where the sky is the limit in terms of power and reliability.
When you think about it, turning the genset on to operate the thrusters is not such a huge constraint.
And depending on the inverters power, it might be possible to drive them without the genset.

 

[jfm]

I can answer that: yep, correct.
The electric pump (which btw is 3-phase, hence requiring a VFD device unless you have a 3-phase genset, but that's a detail) works only at rest, and it can drive the whole lot (STAR stabs, winches, thrusters - though possibly not all together and surely not all together at full power).

Yep
TBH, the electric pack is only of any real use to run STAR. The thrusters are 50hp combined, and the electro pack is 10hp which is already a big motor in the context of this size of boat, and a 50hp electric motor/pump is out of the question. So the only sensible way to power the thrusters is the PTOs. STAR, in contrast, needs less than 10hp

Under way, I don't think there's any logical restriction to keeping the genset and this pump running, but it's pointless when the engine(s) PTO pump(s) are running.

Correct. There is no logical reason, although sometimes there is a reason, called forgetfulness . As part of my winter jobs list (sorry for thread drift but we're all boat geeks) I'm fitting Maretron RIM and SIM (one of each) so I have N2k readout of what's running/turned on/off on the Maretron DSM 250 colour display at each helm. The Maretron gear uniquely lets you write your own labels for what is displayed on the screen so I can write "Elec hydraulic pump running" or whatever text, and that will display on the N2K screens

As I've started the thread drift I'll mention what I'm going to display in case you can think of others - there are 6 channels to each RIM and SIM so I'm planning to display these parameters
RIM http://www.maretron.com/products/rim100.php
port gen running
starboard gen running
starboard gen cooling fan running
electrohydraulic pack running
aft cabin airco running
water maker running

And on the SIM http://www.maretron.com/products/sim100.php
AIS Tx on/off
Either black tank pump running (use a pair of relays to trigger "either" function)
Either black tank orange light on (nearly full)
Either black tank red light on (full)
Transom door open/shut (reed switch)
Fire detect system on

The other thing I have underway already for winter jobs is freshwater flush connectors for both engine, both genset, and the airco raw water circuits, using simple valves and hosepipe connection. Needs some welding of pipe fittings which is underway. I'll post more detail later