Hydraulic drive for an SPX-5??

[whipper_snapper]

So you want to get rid of the existing steering system and replace with a hydraulic one, and then fit an electric pump so an AP can steer the boat?
This wasn't really apparent from your OP and the expense will be considerable just to install a manual hydraulic system, apart from the expense of changing the SPX5.

No!

I want to change the primary steering system from string to hydraulic. The consequence of that is the need to adapt the autopilot to the new steering system.

 

[ianj99]

No!

I want to change the primary steering system from string to hydraulic. The consequence of that is the need to adapt the autopilot to the new steering system.

So you'll need a electric pump as well as an upgraded SPx5 - its not a cheap job overall.

Have you thought about a push pull cable steering system operating on the existing tiller? You disconnect the linkage when you want the existing tiller drive to steer.

This would be a much simpler and cheaper option and lets you keep the existing AP arrangement as is.

http://www.asap-supplies.com/marine/cable-steering-systems

http://www.asap-supplies.com/file_uploads/pdf/Multiflex-Cable-Steering-Systems.pdf - for boats upto 35'.

 

[whipper_snapper]

So you'll need a electric pump as well as an upgraded SPx5 - its not a cheap job overall.

Have you thought about a push pull cable steering system operating on the existing tiller? You disconnect the linkage when you want the existing tiller drive to steer.

This would be a much simpler and cheaper option and lets you keep the existing AP arrangement as is.

http://www.asap-supplies.com/marine/cable-steering-systems

http://www.asap-supplies.com/file_uploads/pdf/Multiflex-Cable-Steering-Systems.pdf - for boats upto 35'.

Hmmm, you could be right. Perhaps I will rethink

 

[yoda]

We have an SPX-5 autopilot with a linear actuator acting directly on the tiller.

We are consider changing the steering to a hydraulic system, does anyone know if there is a hydraulic drive unit that can be used with the SPX-5 'computer'??


I imagine that this will be far more simple and robust in use than a wheel drive or trying to bodge a bypass mechanism for the tiller drive.


Thanks

What you propose is a simple hydraulic steering system as used in 'small' (40ft) motor boats. I know that the SPX10 driving a Type 1 Raymarine pump will hapily do what you want. I don't believe the SPX5 has sufficient output to drive a hydraulic pump. If the primary steering is mechanical and the self steering hydraulic you need a unit with a clutch output (SPX 10) in order to operate a bypass valve so the hydraulic cylinder can 'float' when not in use.

Yoda

 

[whipper_snapper]

If the primary steering is mechanical and the self steering hydraulic you need a unit with a clutch output (SPX 10) in order to operate a bypass valve so the hydraulic cylinder can 'float' when not in use.

Or a simple manual valve. Or more likely a manually switched remote valve to get it as close as possible to the hydraulic cylinder to minimise the amount of oil you are pushing around in 'free flow' mode. I could easily get it to within inches of the cylinder, I don't have a feel however of how much extra work that would make for the mechanical autopilot. Any feeling? Maybe none! after all, it is thoroughly damped by the sea.

 

[ianj99]

What this about self steering?
The steering is rope and pulleys to the tiller. The Spx5's tiller drive steers via the tiller.
I can see no reason to go down the hydraulic route on a craft of this size when a push pull cable system will replace the ropes and pulleys and allow the continued use of the SPX5, or am I missing something?

Going all hydraulic will be costly with the additional cost of a new AP that can drive a hydraulic pump.

 

[whipper_snapper]

What this about self steering?
The steering is rope and pulleys to the tiller. The Spx5's tiller drive steers via the tiller.
I can see no reason to go down the hydraulic route on a craft of this size when a push pull cable system will replace the ropes and pulleys and allow the continued use of the SPX5, or am I missing something?

Going all hydraulic will be costly with the additional cost of a new AP that can drive a hydraulic pump.

How would a push pull be detached to allow the continued use of the SPX5? The backlash from the system would be impossible for it to cope with. At present we dismantle the rope system in a clumsy, time consuming and potentially dangerous way when we want to handover to the autopilot. The advantage of hydraulic is that the hand-over should be much easier. If the cable system works very well I guess we could go back to a wheel drive for the SPX5, but that would seem like a backwards step.

 

[ianj99]

How would a push pull be detached to allow the continued use of the SPX5? The backlash from the system would be impossible for it to cope with. At present we dismantle the rope system in a clumsy, time consuming and potentially dangerous way when we want to handover to the autopilot. The advantage of hydraulic is that the hand-over should be much easier. If the cable system works very well I guess we could go back to a wheel drive for the SPX5, but that would seem like a backwards step.

You simply fit a detachable joint so the push rod end can be lifted off the tiller when the AP is in use or you want to steer using the tiller. There are various fitting accessories listed on ASAP's website. In other words, you keep the tiller and its driven by either the steering cable, the linear drive or by hand. Simples!