I’ve seen some Fish with Trailer fins, under what conditions are these needed? I’m making a 6’8" with 16" tail, with 6"wide 5"high Keel type fins, do I need Trailers? if so how big and where do I put it?
Need trailer fin if your board looses drive, slides sideways, or is just squirrelly.
Don’t need it if you surf it fine.
Adding a trailer box is little trouble, then you can try it first and then decide.
Your fins are on the small side.