As it now sits on the trailer, the aft end of my boat's CB extends about 4" proud of the hull.
Yep, mine folds all the way up into the trunk. Not sure if that is normal or not. Maybe someone with more experience with these boats will chime in. Seems like it should retract more to me.
I may be able to add a keel roller forward of the rear keel roller, to support the aft end of the CB. Any good ideas on how to add a keel roller bracket to the open side of the trailer's cross-member C-beam? The existing bracket is bolted to the face of the C-beam.
I have 2 rollers, one forward of the CB, the other is under the CB. Once on the trailer, I just drop the CB onto the roller. I tried to take a picture, but not sure I got a good one. There are 2 holes driller through the crossmember for the bolts to attach it. The rollers can be adjusted up or down by sliding them with the bolts loosened.
If you do extend a wide-face supporting 2x4 bunk 2.5' aft of the trailer, there may be progressively less support as you go aft of the trailer, due to deflection of the 2x4.
The bunks are 2.5' short of reaching the back/transom of the boat. My plan is actually to bring the bunks to the back age of the boat, but not past it.
The issue with the centerboard is support, rather than position or compression. Without some trailer support points, the CB is only held in place by the pivot bolt and the control lines - not enough for a bumpy road trip. You might consider adding a keel roller to the trailer's rear cross member, if it happens to support the CB, or otherwise be at a good support point. You may also be able to add a keel roller to the tongue using U-bolts.
The CB is laying on the the aft roller when the boat is at rest. I keep the uphaul tied off so it does not dangle in the trunk. I have not had to fix it yet on my boat but I hear that it is common for the rope to get jammed in there (maybe that is why yours CB does not go all the way up?)
What did you choose for bunk material? Trailer stores seem willing to sell carpeted bunks, but at a great premium over dimensional construction lumber. Cedar is naturally rot resistant, so may be a good choice for something that frequently gets wet.
Did you paint the whole bunk, or just the ends to prevent splitting?
I did not make them. They were pre-made. I bought the boat about a year ago, and there were a million projects that I have done with it. Those bunks were sitting around for a while. I knew from the "get go" that I needed to do something with the trailer, but there were lots of other things that impeded sailing that got shifted in front of trailer work. Then one of the bunks started to break loose, so I had to do something sooner than later and the pre-made bunks got used. Now that I know a little more about the boat, I think I will make some bunks in the near future. I am pretty confident that there is beneficial support to them being wider than 4". I am curious too about the best type of wood, etc to use.
Do the bunks, when oriented with their wide face against the hull, conform to the hull shape as a result of being wet and put under the stress of the hull's weight?
Yes. It is much better. Before when they were upright, there was no bend at all and not only did the boat sit on the corners of the bunk, much less of the hull touched the bunks. Now nearly the entire 7ft of bunk it touching the hull (except that little bit of bunk towards the front). I am sure more support (to the transom) would be appreciated by this old boat, but considering what I started with it has to be much happier.