Oil Capacity?? Auto pilot for cable - hydraulic assisted steering- "YOUR FINAL QUESTION FOR A MILLION POUNDS is....."

BruceK

BruceK

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Raymarine do a linear drive for their autohelm but I dont like being boxed in to a supplier that is notorious for not supporting EOL products and that linear drive albeit good is long in the tooth.

I've been told by a number of Nav aid supplier I can put a conventional hydraulic pump system in that will interface with my existing hydraulic actuator but I only need to furnish it's oil capacity and I have to get that right. "It should be stamped on" they say. Only thing is it's behind the engines and where as I believe it is part number "872215" because that is what is attributed to my engines, but cant be sure and it's hidden behind the engines, I see no such stamp to indicate oil capacity on any of the many product photos of it on the internet.

So, has anyone ever tried to determine the oil capacity of their actuator and how did you do so.

Alternately if you are Master of the Volvo Universe. What would it be for KAD 42A twin engine 1993 steering actuator for DPD1/E drives. (Q @volvopaul )

Common gentlemen, I cant be the first to have an autopilot on a 90's boat with hydraulic assisted cable steer by Volvo Penta. They made a half zillion of these things, and they dont all have Autohelm by Raymarine, yet no one seems to know.
 
You can’t determine the oil capacity and can’t use it as you describe. Its a constant flow of high pressure oil from the servo pump and back to the reservoir, when you operate the steering the outer cable which is screwed onto the end of the shuttle valve then pushes or pulls causing the valve to float in or out thus diverting oil to one side of the ram or the other. Your Nav supplier is talking out the back of his manifold, I have installed dozens of autopilots and a hydraulic pump can only work on a hydraulic to hydraulic system, which means you have full hydraulic steering with a helm pump and an extra hydraulic cylinder mounted on the existing hydraulic cylinder, and it is this 2nd cyl that you need to know the capacity of. I have the same setup as you on a Mercruiser i.e. Wire to servo cylinder, and I have an autopilot which is an electric assisted helm which works as normal in manual and when a I switch the AP on a clutch engages and course corrections from the course computer operate an electric motor moving the wire, its a Lowrance unit and talks to my Raymarine plotter for route following and has worked perfectly for 10 yrs.
 
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spannerman said:
You can’t determine the oil capacity and can’t use it as you describe. Its a constant flow of high pressure oil from the servo pump and back to the reservoir, when you operate the steering the outer cable which is screwed onto the end of the shuttle valve then pushes or pulls causing the valve to float in or out thus diverting oil to one side of the ram or the other. Your Nav supplier is talking out the back of his manifold, I have installed dozens of autopilots and a hydraulic pump can only work on a hydraulic to hydraulic system, which means you have full hydraulic steering with a helm pump and an extra hydraulic cylinder mounted on the existing hydraulic cylinder, and it is this 2nd cyl that you need to know the capacity of. I have the same setup as you on a Mercruiser i.e. Wire to servo cylinder, and I have an autopilot which is an electric assisted helm which works as normal in manual and when a I switch the AP on a clutch engages and course corrections from the course computer operate an electric motor moving the wire, its a Lowrance unit and talks to my Raymarine plotter for route following and has worked perfectly for 10 yrs.
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Thank you. I thought I was going daft. Yes I have looked at the Lowrance / Simrad unit. My boat at 34/7 wl/axis and 8 tons seems to be on the outer limit to what they say they can cope with. Mind you they say that is for cable omitting hydraulic assist bit. Questions to the retailers draw lots of ums and ahs with most admitting they have never seen one in the flesh. In your opinion would it cope on my boat? (IIRC it was something like 7 kg of force on a standard steering wheel. Seemed a bit low. )
 
Thats a more advanced version, mine has a simpler control panel without all the bells and whistles, mine just has engage button, left/right buttons for heading change, and nav button for route following from plotter. The motorised bit looks identical, if you have a single installation it should work as if the wire is in good condition and free then its the servo pump that supplies the muscle. Mine is on a 34 yr old Draco with the original steering wire!
 
Thanks. I called Simrad UK and after a few tech passes they came back with an emphatic no. Throws being incompatible. Bit of a bust. Forced to go Raymarine their linear drive has been on back order for more than a year now and Octopus seems a dark horse with people trying to get it to interface with other vendor products.

I wonder how much it would be just to convert to hydraulic steering and take the pain away?
 
As part of the re-engineering project on my Sunfury, I replaced the original VP power assisted Teleflex steering setup with a simple hydraulic setup.
Vetus pump mounted on the steering wheel, nylon hoses and special olives to a hydraulic cylinder mounted to work on the outdrive steering arm then a link bar to link the 2 outdrives together..
All worked a treat and didn't notice the lack of power assistance.
a few things to be aware of...
If using nylon hose, then use special olives that 'bite' into the hose, otherwise it will blow apart. Of course you could use posh swaged hoses from hydroquip or the like.
Cylinder needs to be one with a rod that sticks out on both ends to equalise the piston area, otherwise you get different numbers of turns Right to Left... mine came from Aquafax
Cylinder mounting needs to be pretty beefy, it will take some large loads.
Tie bar - helps if its adjustable to vary the drive 'toe-in', you may be able to use the existing one. I had to make a new one to miss various intercoolers etc and it took a couple of goes to get it right.
Needed to make an adaptor for the steering wheel boss t o mount the wheel.

This was with twin 140 diesels on 290SP drives.... forces may be a bit bigger on twin KAD42/290DP

E&OE!

Otherwise all worked perfectly.
 
Thats the way to go seeing as you have a double installation, then you have a choice of autopilots, I have installed many Raymarine systems and that would be my choice for that setup.
 
tico said:
Cylinder needs to be one with a rod that sticks out on both ends to equalise the piston area, otherwise you get different numbers of turns Right to Left... mine came from Aquafax
Click to expand...

Thank you Tico. Can you show a picture or link to what you are describing here aa it sounds then it would sit between the two steering helmets. I have a tie bar in my setup and the current ram sits starboard to the starboard steering helmet with a tiebar that then joins to the port steering helmet. If I can use existing bracketry that would make things very simple

like so (1)


50881.png

46908.png
 
You already have a tiebar so don’t need to change anything on your present setup. The new hydraulic cylinder screws on where the steering wire would be on the servo cylinder and the long side of the ram goes through the valve on the servo cylinder and connects to the steering arm in place of the wire. You then have manual hydraulic steering which is servo assisted when the SB engine is running. You can then ‘T’ in an autopilot pump on the two hoses coming from the helm pump and the 3rd hose on the AP pump goes back up to the helm pump reservoir to supply the AP pump with oil.
 
Thanks. ? (y) I understand that in principle and it sounds ideal. Finding a hydraulic cylinder to match and fit to do that not so much. I am guessing it's not a ready made, off the shelf affair. If you have done similar could you recommend a matching hydraulic cylinder or where I could pursue this avenue? Many thanks.
 
Thats the type of cylinder... see they also do a full kit including the pump..
I did the same as scarron... made a new mounting bracket for the cylinder and attached it to one longitudinal engine bearer.
 
BruceK said:
Thanks. ? (y) I understand that in principle and it sounds ideal. Finding a hydraulic cylinder to match and fit to do that not so much. I am guessing it's not a ready made, off the shelf affair. If you have done similar could you recommend a matching hydraulic cylinder or where I could pursue this avenue? Many thanks.
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BruceK said:
Thanks. ? (y) I understand that in principle and it sounds ideal. Finding a hydraulic cylinder to match and fit to do that not so much. I am guessing it's not a ready made, off the shelf affair. If you have done similar could you recommend a matching hydraulic cylinder or where I could pursue this avenue? Many thanks.
Click to expand...

They are off the shelf units, I have used Sleipner in the past, there is also Vetus, Seastar and others, this is the cylinder volume you need to match to the AP pump you choose as if its too big it will be slow to react and worse if the cylinder is too small it will react too fast which can be scary in a planing boat. But as long as they are reaonably well matched you can fine tune response rates etc during commisioning.
Click to expand...
 
BruceK said:
Thanks. I called Simrad UK and after a few tech passes they came back with an emphatic no. Throws being incompatible. Bit of a bust. Forced to go Raymarine their linear drive has been on back order for more than a year now and Octopus seems a dark horse with people trying to get it to interface with other vendor products.

I wonder how much it would be just to convert to hydraulic steering , Hydraulics is the way forward , as you have a built in reservoir ie the bilge .
Click to expand...
 
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