I think you will find that the U20 is an awesome sailboat. It was extremely well built with very few issues. That said this is what I would focus on. I have one of the older boats in the fleet with hulll number 31. It was built in 1995. It is still in excellent condition.
One of the few chronic and structural issues with the boat is the compression post under the mast in the forward water tight compartment. Inside the cabin is an aluminum strut that carries the load from the mast through the cabin to the surface of the v-berth area. Under that berth is the forward watertight compartment. Inside that area is a plywood bulkhead that runs along the center line of the boat. It distributes the mast loads down to the sole of the boat. Since it is made of plywood it is subject to rot if the area gets and stays wet. I would check this plywood for integrity. Most of the owners know to remove at least one of the two access panels when the boat is not being used. This allows it to circulate and stay dry. I do the same with the access into the cockpit locker. I put the covers on when I go out for a sail. There is a fix documented that shows how to replace and reinforce this area if the plywood has failed.
A second issue is the main cause of water getting into that compartment. The keel box is also located in that forward compartment. The keel box is molded into the lower half of the U20 mold. There is a seam that connects those two pieces just inside the top of the keel box. This was sealed by the builder with a marine caulk when the boat was built. You can not really inspect the area or work on it practically unless the keel is removed. You will know it is a problem if a lot of water gets inside that compartment. If the area stays dry on a windy day, don't worry about this. If water gets into the cabin, replace the seal on the keel. That part is super easy to do.
Next I would look at the deck and hull. This boat is an end grain balsa cored boat. That is what keeps it light and responsive. But if any of the dozens of screws in the deck are leaking water, it can and will penetrate the deck and saturate the core. On my boat this spring I removed every screw and rebed all the hardware. I had a small section under the spin halyard cheek block that needed attention. I wound up cutting a 6"x6" section of core from inside the cabin. It was not really that big of a deal and I should have addressed this maintenance item when I first noticed it wasn't right. I also went through the boat and properly cored every screw and sealed it with thickened epoxy. This helps prevent water getting into the core if the bedding fails, which they always do. There is tons of information on the internet on how to do this.
If the boat you are looking at has an aluminum spar I would make sure you install the extra lower stays per the class rules. This was added to minimize the chance of mast failure. I have a carbon c-tech spar that does not need this. Check the stays carefully. If there is any signs of corrosion, I would replace them. As this boat does not have a backstay, the upper stays need to be torqued up to 400+ pounds per the rigging guide. I would ask how old the rigging is, and consider replacing just because the cost is insignificant compared to the mast coming down if they fail.
Lastly I would look at the sails. The U20 rules require Dacron sails. This keeps replacement costs down, but as I understand it, the longevity is decreased. Many of the boats at the North Americas will show up each year with a new set of sails. Some will not.
The keel guides are not something I am familiar with. They were added to the boat after mine was built. I would suspect that even if cracked, they will still function just fine. I suspect that Don Corey may have a set that he can sell you. They should not be hard to make though. I would guess they were made out off some type of UHMW. If you have a good table saw and know how to make jigs you should be able to replicate them.
Good luck.
Dave Kennedy
#31 Lighten Up!
