As a designer I say "buy everything new" but as a home boatbuilder myself I don't take any notice of that!

You can certainly use second hand spars on most designs, as aluminium doesn't really wear out, just check for corrosion under fittings and at the heel. Compression failures usually occur near the gooseneck, so check that area carefully. Our Pixie, Quattro 16, Strike 15 and 18, Romany, Gwahir, Strider, Wizard and Gypsy all had used spars.

On the smaller boats (under 25ft) you can use a beach cat mast, but it should be kept as a rotating, not fixed mast because of the profile shape. Most beach cats use the same mast sections, so although choice is limited, you should find something that fits one of my designs.

If you use a monohull mast it is best to have an untapered one because the bigger roach on the mainsail makes the masthead bend more. And you'll need a mast from a longer monohull as multihull rigs come under more loads. For example, the (8m) 26ft monohull I raced had the same mast section as used on a Strider - despite the fact that it was tapered and 40ft (12m) long

When choosing a used mast pay attention to the gooseneck height, the sail feeder and the forestay take off positions. You can usually modify their placement fairly easily, but it's best to have as few holes as possible.

You may well need a one off tabernacle/mast foot. Used booms are never a problem, but check the gooseneck matches the mast.

You should be able to find a genoa that will fit a catamaran. Most monohull mainsails are too full and have no roach, so aren't ideal for a multihull. A beach cat mainsail tends to have an 8ft foot length, which is a bit short for anything larger than a Strike18 or Acorn. It is never worth having a used sail professionally re-cut, just keep looking. But you can modify sails yourself on a domestic sewing machine up to about the 30ft size range.

You can use ex beach cat rudders on most of the trailable designs (we used old Tornado rudders on both our Quattro 16 and Wizard). You may need to modify the rudder stock and tiller to suit the extra freeboard and aft beam position.

Self tailing winches are so much easier to use than the non self tailers that the latter are usually very cheap to buy used. Like winches, deck hatches will fit on any boat so I have often bought them well in advance of starting to build.

Hunting around on ebay usually gets good bargains, I buy a lot of deck and electrical gear there and, although I have had a couple of problems, ebay or my credit card company have quickly sorted them out in my favour.

As always, if you see something that looks suitable ask me and I'll try to help