Vetus hydraulic bow thrusters // Willdo thruster system update

[stefan_r]

I do a reasonable amount of single/short handed sailing and have been looking for a decent bow thruster unit and came across Willdo.

Having spent a fw months analysing and speccing the Willdo thruster system http://www.willdo.eu/ that is basically a big impeller and four independantly controlled hoses that squirt water from holes under the waterline to give sideways thrust...a nice idea and after some research a well built system. Exactly what I want to pin me to the pontoon when mooring/casting off.

Some issues, however. The hydraulic system needs 10hp+ as a power take off from the engines at tickover. My 300hp Yanmars cnnot supply this (surprisingly)...I would need to be turning over at 2,800RPM to allow a 10hp PTO - not quite mooring speed...and no I cannot just run the engine at 2,800rpm when mooring - what if I need to go backwards or forwards!!??

So that scuppered the hydraulic system. They also do a battery system but insist on 24v and that the batteries are separate from existing services or even engines. The motor draws 550amps. Still thinking about this...but costs increase 2xbatteries £2-300 and also charger...complexity etc etc

Finally the impeller unit needs to be 30cm below the waterline. This is awkward and I am not sure if it is do-able....so probably back to the drawingboard.


Sooooooooooooooo what about Verus hydraulic thrusters?????

Anyone used them?

What HP do you need to run them?

Boat is a 37' LOA Sunseeker Superhawk...not massive windage BUT the nose gets wayward if a sparrow farts so I definitely want to get myself a bow thruster...and just prefer the reliability and "always on" idea of hydraulic systems...

 

[npf1]

A belt driven hydraulic pump running off the main crankshaft pulley is surely possible. I looked into this some time ago because of issues using a PTO on my engine and it was possible for 11hp to the hydraulic pump using a twin belt system with a magnetic cluch. Non Vetus mag clutch and hydraulic pump were approx £700 for both, plus you might need a new crankshaft pulley.

 

[jfm]

I think you're way overdoing it. 6hp electric would be very fine on 37foot boat. 4hp would be ok. Fit bigger domestic batteries if needed, but you likely dont need. I dont see that hydraulic offers any advantages over electric at these hp levels, and offers some disadvantages. The oft mentioned unreliability of electric isn't fair to them imho. Builders underspec them and users overuse them and that can cause overheat cut outs, but if you fit a big 6hp to your boat you wont have that problem. In 5 years of having an 11hp electric I've never had it fail or cut out, and I use it quite heavily occasionally, eg for stern to mooring in strong crosswinds. At these low power levels (sub 12hp say) I wouldn't dream of speccing hydraulic

 

[stefan_r]

I have a graph from Yanmar that say (1) for belt driven PTO this is the max HP available at various RPM...a very linear chart and (2) no other PTO is recommended.

Let me assure you if you have ideas PLEASE tell me!!

But Mr Yanmar says at 750rpm (idle) all I can have on a belt driven PTO is one HP.

Please do explain - in layman's terms twin-belt-magnetic clutch etc etc as it sounds very interesting....but Willdo know they have pretty much lost a sale because they need me to find 10hp+ at tickover and I am nowhere near it.

 

[Divemaster1]

[ QUOTE ]
My 300hp Yanmars cnnot supply this (surprisingly)...I would need to be turning over at 2,800RPM to allow a 10hp PTO

[/ QUOTE ]

A bit of a surprise actually ... surely that is to do with the gearing in the pump .... The governor of the engine should pick up the slack to keep her idling at rpm speed irrespective of load (I would have thought).

My old engines, 330 DD's, idle smooth at 450 rpm, and when gear is engaged (similar to engaging the 10 hp hydraulic pump), the governors compensates immediately.. I am considering similar stuff myself and willl look into the hydraulic PTO pump specs now, but 10 hp should in my mind be easy for teh governor to manage as minimum outtake from load at idle is supposed to be 25 hp ....from the spec sheets...

 

[stefan_r]

Hi JFM, not spoken to you directly for a while!!

I have always used electric thrusters...my 46' flybridge has a Vetus 160kgf 24v model and it has never cut out...so I have no issue with them "in principle" - and you're right...I overspecced my thruster on the 46' and it has never failed/overheated/etc. It does run on a dedicated two batteries installed f'wd though.

Hydraulic does seem "nice" however. No more batteries. Not sure what running a thruster is like running off services batteries (or should I take a feed off engine start perhaps??????).

What are the hydraulic disadvantages????? Install is a bit more complex, maybe. What else????

Assuming 4 minutes run time from a leccy thruster that is fine for 99% of situations...and I am happy to spec a battery bank to make that possible.

Just wondering about hydraulics and the "why not" point of view!

 

[stefan_r]

[ QUOTE ]
A bit of a surprise actually ...


[/ QUOTE ]

A surprise to you, me and Willdo.

I had already placed the order - based on their comments "yeah you have more than enough HP to take a diddly 10hp" and then they rang Yanmar and the answer was "no, mate".

Back to drawing board!!!

They have [allegedly] done it with Volvo ~300-ish-hp wit no issues. Maybe 1998 year Yanmars are just a bit noddy????

Anyway they have one more chance to sort the hydraulic Willdo system and then I am back to "normal" bow thrusters...or a very expensive electric Willdo solution.

 

[crunderhay]

I installed a Vetus Bow 55 (4HP) in my Lochin 33 a couple of years ago and it's worth its weight in gold. The Lochin has got a high bow and the thruster throws it around easily.

One advantages of this model over the bigger ones is that it has a 150 dia tunnel, the larger ones are 185 or more. With the top of the tunnel 150 below the water line it allows the tunnel to be further forward than a larger one so gives better leverage.

Another advantage is that it can be run for four minutes before it shuts down, the larger ones are two.

Separate batteries seem a daft way of doing it; take it of the start battery bank but you will need to use 95 or 120 sq mm cable depnding on legnth of run. The cable is expensive but will be less than a separate battery bank and the charging hook up and obviously less space.

 

[davedpc]

My 4hp b/t battery is up in the bow where extra weight is ok. It is supplied by my winch cables which have quite a heavy load rating already. Would't want to faff about with hydraulic hoses and pumps etc.

 

[npf1]

Hi Stephan - I can explain in the context of what I looked into for my boat. Engine is a 115HP Perkins 6354 with two spare groves on the crankshaft pulley. I already have the thruster, so my 'want' was to run the pump from the main engine rather than the current arrangement. Perkins stated that drawing 10 HP from the crankshaft pulley at low RPM was fine.

The solution arrived at involved a tank mounted with solenoid valves etc, a 21cc per rev pump and a clutch with pump mount. Vetus also do this arrangment, but I don't think it is shown in their catalog and it is v.expensive. I also contacted a few industrial hydraulic suppliers to see what they could do.

The clutch and mount was one of these http://www.borelli.uk.com/borelli/elec10.htm Note that it uses an A type belt, so the grooves on the crankshaft pulley will need to match. About £300 for the clutch with mount. In addition I would have needed to get a simple bracket for the engine fabricated. Another nice to have would have been a circuit to cut the clutch if RPM went over a 2000 RPM, so the upper RPM limits of the pump would not be reached.

These guys are specialists http://www.torkmaster.com/ very helpful and a reasonable price. If I recall correctly, £1600 for all the kit needed assembled ready to fit, which was only abut £250 more than the cost of the parts and about 60% of the Vetus price.

I decided not to go ahead due to the cost, but it's still on my wish list.

 

[PCUK]

Can't get 10hp at tick-over has to be nonsense! It is no different to putting it into gear which needs far more hp. I would have thought you would be getting around 40hp on tick-over. Something is far from right here.
Advantage of hydraulic is that it can used continuously if needed, also thrust can be increased by upping revs in bad conditions.
I believe the Willdo pump is constant running with neglible power taken when not in operation so a clutch is not needed.

 

[jfm]

Hi Stefan

I agree the other comments that it's nonsense to say your Yanmars can't develop 10hp at 600rpm

Hydraulics is a way of taking large amounts of power from a prime mover and distributing it to remote places, often several of them. Eg a JCB. But it is loads less efficient than electricity. If you are taking 10hp off the crank you're probably seeing 5hp at the bowthruster. That doesn't matter however in a b/t installation

For sizes up to about 12hp electricity makes more sense. Beyond that the cable sizes get very thick and the required current exceeds what normal batteries can deliver, at 12/24v. So, if given the choice I'd always use electricity. Above about 12hp you dont have the choice - it has to be hydraulic (in practice; I'm not saying >12hp electric motors dont exist, but they tend to be >12v/24v)

Disadvantages of hydraulic are complexity of installation. You need custom fabrications for the PTO on the engines, long pipe runs which ought to be protected from flexing and vibration, etc. Also the electrical answer is independent. If you have a main engine failure with hydraulic, you have 50/50 chance of losing the BT as well, which makes parking tricky. And you have to have the engine running to use the b/t, which you may or may not care about. Other disadvantage is cost - a hydraulic 10hp set up must be loads more £££ than electric

On my Sq58 the domestic batteries supply the b/t and I've never had a problem with that. They are 4 x 230Ah, max 1100A each, arranged in a 2x2 matrix because it is a 24 system