OK I haven't built a Swallow boat, but I spend my winters modifying my BC20. I thought this thread might be of interest for people to share any significant modifications which they have made, which either proved successful, or just proved Matt knew what he was doing in the first place.
So, one serious modification I made, which I have seen on no others and I love, is to fit a boom gallows to support the end of the boom when the sail is lowered. Why did I do it? Several reasons initially:
1-It supports all the spars when I am towing, without having to find and fit the boom crutch (or find you had left it at home...)
2-It supports the boom when the boat is left on her mooring, so it is not swinging about dangling from a topping lift
3-It keeps the boom still on an anchorage, so you don't get all that noise of a boom moving about.
Having built it, I found it have lots of additional uses:
a-It gives a perfect location for lateral navigation lights
b-A hand grip when I am going up and down the stern ladder for a swim
c-Very convenient location for the trailer lighting board
d-Not done yet, but I am going to use it to hold up the aft end of a spray hood extension to form a cockpit tent at some stage.
e-When (not if) I forget to tighten the topping lift before lowering the main, it saves all sorts of embarrassment
It was easy to build. I don't know why everyone doesn't have one. It doesn't interfere with sailing at all. I forget it is even there and many people don't even notice I have got it.