I was told that mold finds the alkaline surface difficult to grow on.
Not sure about mold
but it's good for bugs. If you hate mold you really will hate roaches. Yes, alkaline surfaces repel a lot of things bugs (mold is a bug) is included. It just can't stop it. Moisture with air mixed with heat will make mold. The air carries the mold spores. The ability to repel is not the ability to prevent.
As our CF Sage Gord points out the key is moisture prevention - condensation
makes moisture. Rain makes moisture too. Note the fresh water
The ability to reduce condensation
is increasing the wet bulb temperature in the boat. You can do that with dehumidifiers or ventilation. When the temperature of surfaces are cooler than the air you can get condensation. Enough of that and it dilutes the borax (maybe you never had any). Air carries mold spores and add moisture and heat and it's your bad friend come to call. The alternative is to wipe down all surfaces every single
day for the rest of your life. Could be fun - not.
Good news is roaches don't travel by air! Instead they lay eggs in wod fiber used to make cardboard boxes. In either situation you let them aboard and what do they do? Party!
This goes back to all the thing your mother told you. Never let strangers party in your place unless you invite them. The basics still apply.