Are these the parts you mean? (I don't know their proper names.)Check the bottom tip of the vertical hinge for wear, as well as the cup on the keel latch plate. And look at the spring plate on the deck, is it straight? Worn or bent components will not hold properly,
What are the preferred mechanical properties of this tubing to sleeve over the vertical bolt? Does it need to be soft and flexible, like nylon or rubber tubing, or can it be hard plastic, like a ball-point pen barrel?Clamping the wing nut all the way down does not solve the pop up problem. You need the plastic tube to solve the problem. The problem is the carriage bolt and plate on the bottom of the boat wiggle from side to side without the tube, allowing the rudder to pop up. Fortunately the tube is cheaper and easier than a rudder conversion.
I think now I understand. The idea is to reduce the side-to-side play in the vertical bolt, by sleeving anything over it that will fit over the 1/4 inch vertical carriage bolt but still fit into the groove in the fiberglass transom? I.e. something like this?Clamping the wing nut all the way down does not solve the pop up problem. You need the plastic tube to solve the problem. The problem is the carriage bolt and plate on the bottom of the boat wiggle from side to side without the tube, allowing the rudder to pop up. Fortunately the tube is cheaper and easier than a rudder conversion.
Thanks for the very precise information. I just ordered the PTFE. I'm surprised that 1/2 inch OD fits into that groove, but I suppose it must if you have it on your boat. I suppose it must deform somewhat and wedge in very tightly, which as you say is evidently the point.Try to get some closer to the real tube.
From the forum
The tube I used measures 1/4" ID x 1/2" OD x 5 1/4"+. I know that I bought a one foot length, as I have the surplus on the desk in front of me.
So looking at the McMaster catalogue, and knowing what I would be looking for, I probably bought "Chemical-Resistant Slippery PTFE Tubes"
and not the nylon tube, as I originally stated. The tube I have is white, while the nylon tube is more clear. Have a look at the attached which shows the leftover piece along with an NOS nylon tube and carriage bolt that I picked up later.
The tube does feel slippery. Also, the McMaster catalogue says for "Use Outdoors" and since that where Sunfish live, I likely would have factored that into the decision. Finally, I would have opted for the one foot section over the 5 foot section even though the unit cost is higher. What in the world do you do with an extra 4.5+ feet of tubing? The extra tubing I have has sat in a drawer for the last four years, and will almost certainly be sitting there in another four. Looking at the piece of PFTE I put on the boat four years ago, it looks practically new.
Regardless, I don't think it much matters much whether nylon or PFTE, but I would go with the PTFE as the carriage bolt fits more tightly. The whole purpose of the thing is to resist lateral motion, so the tighter the fit, within reason of course, the better.
The exact number in McMaster for the PTFE tube is 8547K31. A one foot piece is listed at $5.94 plus shipping.
If you or anyone else wants nylon, the number is 8628K27. You do have to buy a five feet however which costs $12.20 plus shipping.
Hope that is helpful.
Attachments
Received and installed today. (The only shipping option McMaster offered me was UPS, $10.15, but in this case that included overnight delivery!)Here’s the tube. I had to increase the hole diameter with a drill bit to fit the vertical bolt through. You want a snug fit.
Yes, I did confirm that, since I still somewhat distrust this clunky-seeming mechanism, and so I think I will want to cinch it down pretty tightly.Just make sure the tube is short enough to allow the carriage bolt to be tightened fairly tight. I don't believe the tube needs to be the max possible length - its purpose is to prevent the bolt from moving side to side.