As Talbot says get some pipe insulation, but if you want to go posh, then fold some canvas, sunbrella or acrylic, whatever you can get your hands on cheaply, over the pipe insulation, and stitch the seam a little way away from the insulation so it's loose. Tuck the seam into the slit on the insulation, and pop over the wires. Looks v. posh, and stops the foam insulation getting little chunks ripped out of it..
Go to your local plumber's merchant (Not B&Q) and buy as many 3m lengths of 22mm Hep2o tube as you need. If you have a very large boat/heating project buy a 25m coil!
This is Okish for short races, but needs reinforcement with pipe insulation for longer races.
Expect to replace the Hep2o every so often as it doesn't like UV much. Mine has done 2 years in the UK and 2 years in the tropics. Wouldn't use it for water systems but still ok on the guardrails.
Worth doing as you can tell the staff to "Hike harder you plebs" whithout getting a load of verbals back.
Otherwise I think West Marine do a line in natty padded covers.
I’ve tried the foam covers, even the expensive one you can buy from the chandleries. This year I bit the bullet and had the guard wires shortened by the length of the cockpit or so and made up some 2 “ webbing straps with triangular rings with bars at each end to fill the gap. Oh what a difference! The whole thing cost me around £20. I wished I done it years ago