Outboard controls, Steering rams


Posted by Paul

Ok, I know I said 2 weeks, but I got a little distracted. It wasnt my fault. What happened was my outboard mechanic contacted me to let me know he was finished working on the motors and ready to help me fit them. I, however wasnt ready so I had to switch tasks and get ready. Which meant I had to stop sanding. I dont need to be asked twice to stop sanding.

And of course that led to another distraction, if I was fitting the outboard gear then I might as well also fit the rest of the steering gear too. I am only part way through fitting the steering rams having fit the helm pump when making the steering riser and dashboard.

So what was required was to finish fitting the aluminium bracket rails that the outboard transom cars will run up and down in. Terry came over to help me bolt it on. Its impossible to be on both sides of the bulkhead at the same time so this was definitely a 2 person job.

Terry jumped inside and tightened the bolts into the rails through the bulkhead. I positioned the rails with sealant slathered on to accept the bolts top and bottom then the rest pretty much found themselves. The aluminium rails have threads tapped into the bolts holes and the bolts thread into them. A word of warning, that goop manages to find a way to get in the strangest places no matter how careful you seem to be.

outboard rails

The cars now run easily up and down and dont bind. Next day I cut the outboard dual controller in next to the helm seat position. I had to be careful not to have the starboard control arm hit the cabin side extension as full power is selected. In the end I could have mounted the controls about another 100mm further forward but I wont know that for sure until I get the morse (push pull named after the guy that invented them not dot dot dash) cables. Standard length is 3600 and I measure it to need 3500mm in its current position and exactly 3600 if 100mm further forward. I didnt want to find out the hard way I got the measurements wrong. These cables need a bit of radius to go around a corner so I am just being safe.

outboard controls

outboard controls. 1JPG

outboard controls. 2

What those pics dont show is the protrusion below deck in the aft bedroom. I will hide it with another wall with cupboards around and will show pics of that when I build it all. The starter keys that came with this second hand unit will go into the dashboard. The only other thing I did was make a plywood pad for the controller to sit on just to raise it higher than standard deck level to put less pressure on the seals that will drip into the bedroom if it leaks, by being on a ply pad water wont run past the seal on the slightly sloping panel because the ply pad lifts the seal up higher than the deck.

So I thought the other thing (prior to launch) I must have working besides motors is steering. I have the helm pump fitted, the other end of them are the rams. So I decided to start fitting them too. And I made a little error. Actually I followed the instructions exactly and that didnt work as I had planned. So now I am adapting. Let me explain.

I had no idea what steering to buy. A friend building the same cat in Qld, Sean, told me what he was installing and where he got them. Way way cheaper than the local suppliers, he recommended Uflex (short for Ultraflex), made in Italy but bought in the US, back when we had parity with the US$. The exact set up is slightly over spec for the application and I knew as soon as I got them that I had a little problem that would need solving one day.

One of the great things about these builds is every one is different. Every builder has a slightly different take on the design, where to fit things, how to fit them etc. I didnt bother to ask Sean how he was fitting his because that involves where the rudders were hung, were they kick up, his tiller set up etc, and again, I already had much of mine so if his set up was different in any way, how he was mounting his rams would not be the same as mine.

I knew as soon as I got the rams that I did not quite have enough room to fit the rams square to the tillers. When hard to port on the starboard hull or hard to starboard in the port hull, the opposite end to the ram hits the hull side by about half way through. Its only about 50mm but its enough to need a hole in the hull side. So I always planned to put a hole in and make a cap and glass it on. I even thought I could make even more use of that protrusion and fit a U bolt at the end of the cap as a dingy hitch point.

But when I followed the instructions, it told me I should mount the ram square to the tiller but in a line different to what I thought it would. Perhaps a little more explanation of how these rams and tillers work. If you draw a line square to the tiller in its exact fore and aft position through the middle of the bolt hole that line is parallel to the bulkhead. But as you turn the tiller through its 30 degree arc one side or the other of centre, the bolt hole moves in an arc.

How the fixed ram deals with this motion is a floating universal joint at each end, the mounting point for the ram to the tiller is a ball joint and the mounting point for the ram housing also has universal ball joint, albeit with less movement. That combination deals with the arc that the ram will work through at dead center or the points during the arc to its full movement through to a maximum of 35 degrees.

The instructions specify to have a 200mm tiller, which I have, in fact I have a slot instead of a bolt hole to attach to the tiller which allows for up to 220mm or down to 180mm.

Where I initially got into trouble is that I thought it would instruct me to fit the ram square to the tiller at dead ahead. Wrong. It tells me to fit the ram square to the tiller at the maximum wheel rotation, either port or starboard the arc is the same. Then the ram comes off parallel in its ball joints. Not the other way around.

This moves the mounting position aft just enough to be a damn nuisance in just about every way, from drilling the mount holes to where the ram will protrude through the hull and how far.

The ram hole protrudes in just about the most difficult place it could for me to mount the cap to. See for yourself.

ram exit from inside

ram exit from inside 1

steering ram exit conduit hole 1

steering ram exit conduit hole

steering ram exit conduit

ram conduit

As you can see, the tiller protrudes at just about the worst possible place. Just 50mm forward of there and it is in the chamfer panel, under the bridgedeck, out of the way.

Then I experimented with the ram mounted in different places. It was then that I realised there was way more play in the ball joints than I would ever need and I could in fact mount the ram at just a slight angle without re-positioning the tiller to rudder angle and the ram would still work through its arc without putting any pressure on the ram arm. I know this because I could hold the ram head to the tiller with my hand through its entire arc, if I could hold it with just my hand then a M16 bolt would have no trouble holding it and the ram remained well within the scope of movement of the ball joint so the ram arm is safe from any bending stresses.

revised steering ram position

And that solves all my problems. All except filling the hole I have drilled through the step edge. Not a big problem, just annoying. I perhaps should have thought this through to where I am now before I drilled the hole. To help fill the hole I will glue a length of dowel (my broom handle is about exactly right) into the hole, glass over from inside and fill with filler on the outside and reshape the step edge.

The hole will now be on the chamfer panel about 50mm forward of the old hole, which means a flat hull side to fit the cap to. The ram mounting holes are now closer to the shelf edge meaning easy to drill but more importantly easy to get to the bolts and nuts.

This work will push me back a week or so. Next week I will get the rest of the sanding finished because I have booked some help (Terry and maybe Ray) to help me roll the International microsurfacer on the week after next.

Must crack on.

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