The Bristol 35 like the 39/40 was sold as both a center board and deep keel
boat. All they did was cut a foot or two off the keel and use cast lead ballast glassed into the encapsulated keel with a slot for the board. The boat will sail just fine without the board but will have more leeway going hard on the wind
. On every other point of sail it will actually sail fine though be a bit more tender
the deep keel version. Have no idea what the center board is on the Bristol but assume it's a foam filled fiberglass
laminate with possibly a little lead in the tip so it will sink when you want it down. Should be a fairly easy lay up for an experienced glass worker. The critical part will be getting one to copy or the plans to build one. Bristol boats is long out of business and the B35 one of their older designs so doubt if you'll be able to get any help from the business. Best bet would be to go on every sailing website, blog, etc asking for someone with a center board B35 to send you photos and dimensions of their board. Also check the 'For Sale' sights for a listing of C/B B35's for help.
Have a C/B Pearson
35 which is a contemporary to the B35 though it was designed as C/B only. The board is a fiber glass laminate with a little ballast in the end so it will sink and a hole for a pin at the top. It's raised by a cable about a 1/3rd of the way down from the pin. The winch
is two sheaves, one large and one small sandwiched together. The large sheave is wrapped with the hoisting cable and the diameter gives mechanical advantage over the smaller sheave which the lifting cable is wrapped around. The hoisting cable runs through bronze tubing attached to a sheave in a water
tight housing in the keel to stow the board. The C/B housing is a cast lead ballast piece glassed into the encapsulated keel. The pivot axle is a piece of bronze round stock about 1/1/4" diameter mounted in two flanges with screwed in caps that look like they are common plumbing hardware
. It's all pretty simple engineering but I'd have a close look at the boat to see if any of this hardware
is still on the boat. If not, you'll have to figure out how to resurrect it should you want to install a board. IIRC, the Bristol used a reel winch
for the center board. Don't quote me on this as it's been more than a decade since I looked at a C/B B35.
Have owned two center board 35' boats. Have used the boards very seldom. About the only time I drop it is short tacking in very tight channels. The leeway wasn't/isn't an issue for me as a cruiser. If you have a lot of hard on the wind
sailing or want to race
, might be worthwhile to replace the board. One couple who circumnavigated on a C/B Tartan 37 removed the board before they left on the cruise