Hydraulic thrusters / bow and stern

[Deleted User YDKXO]

But don't dismiss electric thrusters just because "hyd is better".
.

I'm not dismissing them and, in truth, I've never had any problems with electric thrusters fitted to any of my boats. However, the proportional control and hold feature of the hyd thrusters are worth having IMHO (although maybe those are available now on electric thrusters now, I don't know) and IMHO a hydraulic drive system is inherently more robust. Obviously the big difference is cost which is why you don't see hyd thrusters below 60-70ft

 

[jfm]

I'm not dismissing them and, in truth, I've never had any problems with electric thrusters fitted to any of my boats. However, the proportional control and hold feature of the hyd thrusters are worth having IMHO (although maybe those are available now on electric thrusters now, I don't know) and IMHO a hydraulic drive system is inherently more robust. Obviously the big difference is cost which is why you don't see hyd thrusters below 60-70ft

You can definitely have proportional control on electrics Deleted User, but I'm not sure that continuous running and "hold" are available. I've never used "hold" to be honest. Solution to a problem I don't have...

 

[Deleted User YDKXO]

I've never used "hold" to be honest. Solution to a problem I don't have...

I suppose its only useful if you're singlehanding and you need to hold your boat against a pontoon or another boat to sort the lines out

 

[MapisM]

The other thing I have underway already for winter jobs is freshwater flush connectors

Now, why does that sound familiar?
The main problem should be the very big dia hose required by the engines. At least a couple of inches for each Cat 32, I guess?
Though of course you might flush them one at a time, to reduce the overall flow required.
Did you have the fresh water tank already pre-built for that?

Re. other Maretron messages, I suppose the port genset doesn't have a cooling fan, or did you forget it?
Other than that, I can think of:
for the RIM, e/r vents (though in some boats they are noisy enough to be self-noticing - 'dunno about yours), search light and bilge pumps.
for the SIM, maybe passerelle and swim platform (in/out and up/down respectively)?
Just quick thoughts.

 

[jfm]

Now, why does that sound familiar?
The main problem should be the very big dia hose required by the engines. At least a couple of inches for each Cat 32, I guess?
Though of course you might flush them one at a time, to reduce the overall flow required.
Did you have the fresh water tank already pre-built for that?

Re. other Maretron messages, I suppose the port genset doesn't have a cooling fan, or did you forget it?
Other than that, I can think of:
for the RIM, e/r vents (though in some boats they are noisy enough to be self-noticing - 'dunno about yours), search light and bilge pumps.
for the SIM, maybe passerelle and swim platform (in/out and up/down respectively)?
Just quick thoughts.

Yes, I fully admit that you posted this idea ages ago (!! ) and it's come up in a few discussions on here. I'm just finally getting around to it, and forgot to do it as part of the build spec. Have you done it? - I can't remember.

The flow rate is ok from a hosepipe. I measured it. My hose will do about 50 litres/minute with a 3/4inch pipe, and running one C32 at slow idle 550rpm that's enough flow. One at a time. So I'm having 1.25inch bsp elbows welded to the side of my strainers, with ball valves, then 3/4inch hose connectors

Gensets and airco are easy - more than enough flow from the hosepipe

Thanks for RIM/SIM thoughst. I already have bilge-high alarms and pump running indictors/klaxons that come on after the pump has been running 20 seconds. Searchlight is never turned on my boat! I only had one genset charge air cooling fan fitted - long boring story. E/room vents, yup, hadn't thought of that, thanks

Passerelle has to be in else I cannot shut the transom door so that is self-indicating. Swim platform is linked to engine start circuit and a bleeper, so no possibility to drive off with it down (with manual overrides/ key switch)

Indication of windows open in the hull would be nice, but it would be a huge mission running the cables from all the microswitches so that one is not on my short term list

 

[jfm]

Just curious, ...the crane: that is also on separate hyd pack, I suppose?

Yes. Those Besenzoni cranes come with a little hydraulic pump/pack built inside them so you just connect 24v cables and that's it. Likewise, the folding bimini has its own hydraulic pack, which is a marinised version of a unit used in some convertible cars to open and shut the canvas/tin top. Blimey, that means I have 6 separate hydraulic packs on the boat: main thrusters/stabs, platform, passerelle, bimini, crane, flaps.

 

[MapisM]

Have you done it?

Nope, never made it, but looking forward to hearing more about it.
Btw, I would have never expected a 3/4 pipe to be big enough for engines like yours, but I guess you did the math.
By that token, the 1" connection to my fresh water tank would be plenty also for my engines!

 

[jfm]

Yup I did the math
My maths isn't based on what the pump pumps, because I don't care if the pump is a bit starved and cavitates etc. So long as the pump is wet, it is lubricated.
My maths starts with the fuel burn 9 litres per hour, and the calorific value of that fuel, and the specific heat capacity of water, and you see that water raised 30 deg C or so will take out half that heat. Something like that - I don't have the maths in front of me. The other half (more than half, actually) goes down the exhaust pipe anyway. In any case, I have the options to fit a boost pump to get say 80 litres/minute, and do the procedure with cold engines, so I'm going to carry on with the experiment!

 

[MapisM]

My maths isn't based on what the pump pumps...

Aha, I see what you mean.
And after all, the flushing only takes a very short time, so if done with cold engines, neither the block nor the exhaust would have the time to overheat anyway.
Yep, coming to think about it, as long as the pump impeller is kept lubricated, the heat considerations are not so critical.

 

[kcrane]

Below 60 foot electric 24v is more sensible. Sure you are limited to 3 mins continuous or whatever, but the absence of a hydraulic pack (oil tank oil filters valves pto pumps coolers etc) and then hoses to both ends of boat is probably worth having

Just thinking about that running time limitation (as opposed to the power requirement) but I'm not shy of using both thrusters (I quite like moving off a pontoon sideways) and even I am struggling to think of a time when I've used them for more than 10 seconds continuous. Has anyone ever needed anything like 3 minutes?

 

[jfm]

Just thinking about that running time limitation (as opposed to the power requirement) but I'm not shy of using both thrusters (I quite like moving off a pontoon sideways) and even I am struggling to think of a time when I've used them for more than 10 seconds continuous. Has anyone ever needed anything like 3 minutes?

I agree your sentiment and I agree electric is generally the most sensible choice up to say 60-65 feet of boat.

Don't quote me on the 3 minutes - I said "whatever". I don't know what the actual time limit is but point is these motors tend not to be continuously rated. If you were reversing into a tricky med berth in a crosswind and encountered a problem, or even if you didn't encounter a problem, you might well like the freedom to use them for quite a lot more than 10 seconds though. Still, even with some time limitation, I'd still choose electric on a 60 footer. All these things are compromises

 

[MapisM]

even with some time limitation, I'd still choose electric on a 60 footer.

+1. And I'm sure you mean it even if the boat would be hyd stabilized.
Robg71, are you hearing us...?
Btw, I guess you'd appreciate spending a bit less, on top of choosing the best compromise.

 

[Jamesuk]

![/QUOTE]
Hydraulic probably including installation.

As for the heat cut off, we can run our electric bow thruster continuously for 3minutes before the thermal cut out kicks in (Side Power). The most u have run ours for was about 5 seconds at 48volts (20hp).

With hydraulic you might have to start your generator if its Set up that way so that's a fuss. But I'd choose hydraulic over electric just like the person above mentioned you can run it all day if you have the fuel

There is a limit to the power you can practically generate with DC electrical systems, so for super yachts and other larger heavier crafts DC thrusters are rarely an option. The greater thrust and extended run time make hydraulic thrusters the ideal choice for commercial crafts and other less manoeuvrable yachts. In conjunction with a good hydraulic system these thrusters offer continuous operation and you can get variable speed control with proportional control and valves. Our hydraulic thruster range from 100 to 550kg of thrust for use as either bow or stern thrusters.

For more information about these hydraulic thrusters, please click one of the images below.

Choose a hydraulic thruster if you need it for more than close quarter manoeuvring.

Hydraulic thrusters offer two advantages compared to electric thrusters. In conjunction with a good hydraulic system these thrusters offer continuous use. This is often necessary for boats such as fishing trawlers, small ferries and some larger yachts where thrusters are used for more than close quarter manoeuvres. The other advantage of hydraulic thrusters is the ability to control speed by means of a proportional control valve. With models from 100 kg to 550 kg of thrust for use as either bow or stern thrusters, Sidepower probably has a model for your boat.
http://www.side-power.com/public/templates/default.php?id=21&selected=91&selected2=21

 

[MapisM]

Hydraulic probably including installation.

As for the heat cut off, we can run our electric bow thruster continuously for 3minutes before the thermal cut out kicks in (Side Power). The most u have run ours for was about 5 seconds at 48volts (20hp).

With hydraulic you might have to start your generator if its Set up that way so that's a fuss. But I'd choose hydraulic over electric just like the person above mentioned you can run it all day if you have the fuel

There is a limit to the power you can practically generate with DC electrical systems, so for super yachts and other larger heavier crafts DC thrusters are rarely an option. The greater thrust and extended run time make hydraulic thrusters the ideal choice for commercial crafts and other less manoeuvrable yachts. In conjunction with a good hydraulic system these thrusters offer continuous operation and you can get variable speed control with proportional control and valves. Our hydraulic thruster range from 100 to 550kg of thrust for use as either bow or stern thrusters.

For more information about these hydraulic thrusters, please click one of the images below.

Choose a hydraulic thruster if you need it for more than close quarter manoeuvring.

Hydraulic thrusters offer two advantages compared to electric thrusters. In conjunction with a good hydraulic system these thrusters offer continuous use. This is often necessary for boats such as fishing trawlers, small ferries and some larger yachts where thrusters are used for more than close quarter manoeuvres. The other advantage of hydraulic thrusters is the ability to control speed by means of a proportional control valve. With models from 100 kg to 550 kg of thrust for use as either bow or stern thrusters, Sidepower probably has a model for your boat.
http://www.side-power.com/public/templates/default.php?id=21&selected=91&selected2=21

Blimey, that's a proper advertising post, if I've ever seen one!

That aside, I'm curious about the 48V thruster you mention, 'cause I never heard of any. Would you care to elaborate further?

Oh, and just in case you thought to impress us with 550kg hydraulic thrusters, think again.
There are electric thrusters on the market which are capable of 2000kg, and I'm only speaking of those I'm aware of - there might be some even bigger, 'dunno.
Of course they are AC 3-phase, not DC. But on the boats they are meant for, that's a problem which doesn't exist, 'cause they have AC available 24/7.