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Old 13-11-2006, 07:29   #1
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Which is more reliable: electric or hydraulic?

I am speaking specifically of powered hardware like windlasses, bow thrusters, winches and furlers.

IGNORING cost and installation issues...

Image two otherwise identical 50 foot cruising boats, one equipped with electric, one with hydraulic, latest technology. Assume both are properly sized and installed. Which boat would you take offhore?

Again I am specifically wondering about RELIABILITY OF THE DEVICES. Not necessarily the systems supplying the power.

To me first thoughts suggest hydraulic. No 12V to get in contact with weather/water. No motor to burn out. Overloading a device may be less catastrophic (in terms of damage to the device) on hydraulic.

Would hydraulic be easier to service in the field (I am thinking of spare parts)?

I know little about hydraulic systems, thus my question. An old salt at a local yard claims properly installed hydraulics are ultimately more reliable and easier to service.

But, have 12v devices evolved enough to be superior?

Experienced offshore sailors, what say you?
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Old 13-11-2006, 08:02   #2
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Ultimately hydraulics are more powerful and possibly more reliable. On the super yachts all the stuff is hydraulic for the most part. However for most of us electric is easier and not that much less reliable. Also you won't have fluid everywhere if/when a seal goes. If I was to automate the whole boat, furlers, winches, windlass, bowthruster, backstay, vang, etc the hydraulics make much more sense - one motor and you have powered up the whole system - you just push the magic button. OTOH if I was just doing one winch and a windlass - electric is much simpler and cost effective...
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Old 13-11-2006, 11:10   #3
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Manual!

Seriously though... hydraulic is more reliable, as there are fewer problems to be had in what is a less complex system.
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Old 13-11-2006, 23:59   #4
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Lightbulb From a person who has to work on both..........

Hydraulics’ are more dependable but more expensive. The problem on boats under 40', or even 45', is power to operate the pump(s). A diesel driven unit would be best with a back up 12V system. You would have to have one large set of batteries to run on a 12V single system for very long. It has to run continuously unless each item had it's own pump, which makes it even more expensive.

1-4 items running on independent pumps wouldn't be too hard on power draw. But more then that a diesel would be more efficient especially with power assist steering, which needs a continuous run, and with exception for autopilots.

A windlass should be on an independent pump for a couple reasons. One it's not used much and two it's all the way forward away from the main system.

Hydraulics are much more user friendly on power boats because they always have a motor running.

Over the past 10 years, in our shop, we have seen a major change from electrical to hyd. power driven attachments. exempli gratia: Jib cranes, cement brakers, water pumps, all sorts of motor driven equipment, plows, sweepers, conveyors and etc.

All the new utility trucks are equipped with a hyd. tool circuit that runs 9+ gpm @ 1800 psi.

As far as leaks, that's up to the owner/operator. Proper installation and maintenance is the key. One nice thing is, if it sets for a long time, it will not corrode like an electrical system will. It may start to look bad on the outside but the inside will stay fresh as long as the water is kept out of the oil. If an electrical system looks bad, it probably will be.

More Hyd's is in the future for boats! That's one of the reasons I put in a manual hyd. steering! It just keeps getting better and more user friendly with time! And I would not go back to mechanical steering.

I can go on but I need to catch my breath..............................._/)
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Old 14-11-2006, 07:34   #5
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You know... I just noticed the 42' length of the boat you're speaking of. I would highly suggest manual devices aboard a boat of this size, as opposed to electric or hydraulic if you want reliability. As Del points out, the hydraulic systems are more reliable, but they do indeed eat up a lot of power to drive the pumps.

A manual windlass and manual winches would go a long way toward reliability. Of course, a bow thruster would need to be electric if you so felt you required one. I'd suggest that if you are looking at all this equipment for an as of yet unfinished boat, you might want to get out on the water and see if you really need to spend all the $$ on it.

We have a 45' sloop using manual winches, manual windlass with 45lb CQR and no thruster of any kind. I have no trouble operating this boat in any conditions and my wife pulls up the anchor in most cases. You might be heading toward overkill by putting in all of those systems - each will be a potential spot for problems. Why not simplify?

PS: I'm imagining you are in good physical shape since you are building that 42 footer?
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Old 14-11-2006, 09:58   #6
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Seems no matter how simplistic you ask, responders will insist on (trying to) read between the lines. Nothing personal Sean, I am just venting from my experience from posing questions on the internet.

Hence I tried to make my question simple: All things being equal, which is more reliable: electric or hydraulic?

Now to address the rest of your recommendations...

"Manual devices on a boat this size..."
Owners are installing electric devices (thrusters and windlasses) on boats this size all the time. (thruster installation on sail and power boats accounts for a lot of the jobs my wife sees, read below)

"You migh want to get out on the water..."
Well I have been out on the water . For at least fifteen years. Sailboat. Lived aboard. Cruised the carribean. Practically rebuilt (mechanically) a 28 foot heavy displacement sloop. Yes, my wife usually pulls up the 120ft (max) anchor chain. She is the one that wants the windlass .

On the need for a thruster on this boat. This Westsail is a VERY full keeled boat (though not as full as the 32s), sharp close quarter turning is not one if it's strong points. When building out, best to spot the tunnel early so you dont need to rip out stuff later. The tunnel is already installed BTW.

I am not leaning in any direction: manual, electric, hydraulic. For these systems we are at the data gathering stage. It will be a year or so at least before a decision needs to be made. I know the least about hydraulics, hence my question.

Now, more info on me and this particular buildout: Yes I consider myself fairly young and healthy (barely 40). I am trained in physics, have a lot of experience in electronics, rebuilt a boat, rebuilt motorcycles, written (and continue to write) commercially successful software, and am just an all around geek. My wife is a marine geek (more than myself I would say) has been working in the marine buisiness (cabinetry, wholesale supply, repair and construction) for 15 years. Hope that meet's readers minimum credentials.

This buildout will eventually be the "retirement home", so getting it done as soon and as cheaply as possible is NOT how we are doing it. We still have our sloop and will continue to have it as long as we have time to enjoy it (though we are trimming our motorcycle time in order to buildout, which is a bummer). A lot of time is going into the design based on what we know from our experience on our sloop, what we have seen on other boats, and what we see coming in the trade. We know very well owning, buying, or building boats is not a sound investment if all you are interested in is a financial return. So, $$$ is not that big an issue for us. This is a life investment.

Sorry Sean, you got me rambling.

Now back to this thread on hydraulics: while browsing the Vetus catalog, I noticed they seem to supply fairly complete systems well suited for smaller boats (which I would define as under 60 feet). You can even get most of their smallest thrusters and windlasses with in a hydraulic version. I have not seen any other vendor with as much selection. We were at IBEX a couple weeks ago and EVERYTHING was electric. My guess is that it is easier for builders to install and replace on production boats.
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Old 14-11-2006, 10:37   #7
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Sean-
But aren't "manual" winches ultimately electro-hydraulic once the wetware is used to operate them?<G>

Learningcurve-
There's no such thing as an abstract "better" in boats, it is all a question of "horses for courses". Which is better, a plough horse or a quarter horse? Depends on what you plan to do with them, even the glue factory will have an opinion on that.<G>

Hydraulics and electrics have different failure modes, different costs, different maintenance and other issues. You can't judge them in the abstract, because nagging little issues like "But there's no room for a hydraulic pump!" will always get in the way. The more specific you get with a context, the more valid the comparison can be.
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Old 14-11-2006, 11:34   #8
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The answer is....

All one has to do is look to the commercial applications. They are ALL virtually hydraulic whether or not they are marine applications or on land. One huge reason is reliablilty. I have asked many people who were responsible for maintaining either commercial fishing boats or construction gear. Their answers were always "reliability of hydraulics was unbeatable".

One maintantence manager told me that as long as the hydraulic lines were not physically damaged by some stupid operator all that he had to do was make sure that the hydraulic fluid was kept clean by changing the filters. Let the filters go unchanged or seals go without replacement and he had failures.
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Old 14-11-2006, 12:08   #9
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I must add.......

Time and/or heat will eventually take out the seals. 5-10 years under normal operating conditions. But they are usually EZ to replace by an experienced hyd. mechanic.

Also there are different types of hyd. oils now. One is used in carwash facilities, which is water based and dissipates in water (bio, blue in color).
Another is soy based and used in large mowers, so if they leak they don't pollute the ground (in minor amounts).
A third is most common in government heavy equipment and a biotype called Clarity, which will mix with the petrol, based hyd. oils.
And then there it the standard AW petrol oils.

Boats usually run the petrol types with water resistant inhibitors.............._/)
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Old 14-11-2006, 12:16   #10
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I would agree that if reliability is your only metric, than hydraulic is a clear winner. But that's a lot different than saying it's the practical choice for cruising boats. I would probably prefer 12v cables running through my boat than hydraulic lines everywhere. The other option is multiple hydraulic pumps which then hurts the reliability issue. I think that the real advantage of hydraulics is the enormous strength and power that they can generate with a small pump. So windlass yes, but furlers and other loads I don't see needing so much power on a 42' boat.
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Old 14-11-2006, 13:55   #11
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Originally Posted by hellosailor
Learningcurve-
There's no such thing as an abstract "better" in boats, it is all a question of "horses for courses". Which is better, a plough horse or a quarter horse? Depends on what you plan to do with them, even the glue factory will have an opinion on that.<G>
Well OF COURSE! Here again, my original post is misunderstood. I am not making claims for what is "better", NOR am I asking for someone to claim which is "better". Not offering context was intentional due to all of the tangents that stated, assumed or inferred extraneous details tend to generate (already happening in this thread).

I was merely seeking the experienced collective's opinion, let me try and restate my original hypothetical question...

You need to escape an exploding volcano on an island real fast and go offshore. You have two boats to choose one fitted with electric gear, one with hydraulic gear. Otherwise, the boats are identical. Which would you pick and why?

Sheesh, trying to stay on thread is like trying to herd cats!
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Old 14-11-2006, 14:02   #12
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"You need to escape an exploding volcano on an island real fast and go offshore."

Oh, then I'd absolutely pick the one with the hydraulics, knowing theyu would come with a much bigger faster boat attached.

No, wait a minute, maybe I'd pick the one with the electrics, because there are no hydraulic boats at the dock.

Wait a minute, aren't volcanoes hydraulic? Isn't that stuff dangerous? <VBG>
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Old 14-11-2006, 14:19   #13
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Wait a minute, aren't volcanoes hydraulic? Isn't that stuff dangerous? <VBG>
Heh, all you guys are fun a games. Can anyone be the slightest bit serious on this forum?
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Old 14-11-2006, 14:41   #14
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Hey Learningcurve. We're the same guy! I also have a BS in Physics, used to work for NASA, I'm 35, had a software development company, then got out of all of that and started crewing, chartering and eventually just living aboard my boat while developing software - which is what I do now. (Java and C++/MySQL).

What you'll want to get used to on this forum is that people here are sailors and boat folks. We're pretty easy going, and will often banter about as well as suggest things that are "outside the box." Its the nature of the game. There have been times I have asked questions on here that seemed black and white at first, but then somebody piped in with a completely "out of left field" response, which worked perfectly for me.

This is also the nature of an online forum in general... not everyone can be as precise as you and I were trained to be. In fact, I have been trading in my precision over the years for a more relaxed approach.

I had already answered your question though: Hydraulic is the optimal system for reliability, not factoring in other issues.

PS: If I were racing away from the volcano though... I'd still go with manual.
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Old 14-11-2006, 15:01   #15
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This is also the nature of an online forum in general... not everyone can be as precise as you and I were trained to be. In fact, I have been trading in my precision over the years for a more relaxed approach.
I use to be a perfectionist, then I found out I wasn't so perfect. Perfection is only in mathematics + or - 50/1,000,000th

PS Hydraulics' ARE more dependable just not as economical in smaller applications.

There................................._/)
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