Aboard my Mainecat I use only one board full down unless I want shoal draft
performance then I do like Tracey Sailing school
, i.e. both with the tops flush with the deck
Off the wind
in a seaway, they can rattle a bit when down but you don't need them then and hoisted up they are quiet. I have had two daggerboard boats in a row (Mainecat 41 and F-28), neither one ever had growth issues in SoCal or PNW. I did paint
the lower part of the board and trunk but in any event it simply was not a problem.
Today, I was out sailing and tried changing boards to ensure that the leeward one was always down. Easy enough as the boat goes head
to wind but it's totally unnecessary, same balance, same performance.
The MC 30 only has one board and John Shuttleworth
I think, designed some with only one board. Basically, it's like twin engines, you get redundancy. They can break, or get chewed up and having a second one gives me peace of mind that I won't have to stop sailing while waiting for a new one or to build it.
During my exercise with a custom cat design, I got figures from the designer
on comparisons between a LAR (low aspect ratio) mini-keel versus a daggerboard. The effectiveness of a board is hugely greater than a mini-keel. It's what got me using a single
board. Basically, (and some number cruncher can correct me) it seems to work out that even a single
board at the depth
of a mini-keel is still superior to a mini-keel.
Just my $0.02