We have a custom mooring cover made by King Marine Canvas in Seattle that we've been very happy with. We ordered the cover while the boat was still being constructed. King Marine Canvas does a lot of canvas work on Ranger Tugs and despite having previous patterns for an R27OB, Dave (the owner) preferred to pattern our specific boat to ensure the cover was exact. Once construction of the boat was completed, Dave went to the Ranger Tugs factory and measured the boat. There are several places to get covers but the best one may be from a competent marine canvas business that's local to you.
Our cover was intended to protect the boat while it was stored on the trailer in a heavily treed area. A couple of things I wish I had considered before we had the cover made:
We anticipated occasionally storing the boat in areas that didn't have shore power, so I had a window installed in the cover that aligned with the solar panel. What I didn't anticipate was that the stock solar panel would not be sufficient for the way we used the boat. We eventually removed the stock panel and put two other panels in its place, so the window doesn't align now. Read all you can on Tugnuts regarding modifications, and if you anticipate making any of them, take that into consideration before you have the cover made.
I also didn't specify that the swimstep be covered and I regret that now. When the boat is stored under the cover the swimstep is generally grungy from pollen/dirt and the motor well is surprisingly effective at collecting tree debris that plug the drain.
If you're storing your boat on a trailer in areas that get below freezing, the cover can significantly help keeping the temperature up and the humidity down. Custom covers are really expensive but we've never regretted purchasing one, even now that we moor our boat in a covered slip.
