One of my favorite topics!
A three piece hull consists of a hull, deck and deck cap. A two piece hull has a hull and a 1 piece molded deck/cap/liner.
Negatives of two piece.
First, there's no toe space around deck. Like fishing out of a bathtub...impossible to brace against deck cap when fighting a fish, working lines or hauling pots (that's crab pots). Some 2 piece hulls try to get around this by cuttin' out an area and putting in a plastic "rod storage area", that goes almost to floor. This usually turns yellow in 2 or 3 years. Try to walk around a Sailfish CC sometime. Need to be Spiderman to walk around console.
Since two piece hulls are the cheapest to build, they are usually found in cheaper boats.
No way to secure hull to deck seam other than sheet metal screws (can't get to back side for nuts) and or caulk/glue products. Often, no access to underside of deck for plumbing/wiring issues or access to underside of deck cap. Ever wonder why some rodholders have those stupid little drain pipe nipples and rubber covers? They drain inside hull
. Imagine having to "un-cork" a rod holder everytime you wanted to use it!
Here's a biggie for me. Since we have cheaper boats built two piece hull style, there's more ways to save money. Instead of a heavy, self-supporting hull...let's build a thin fiberglass hull, a thin inner liner and sandwich void with foam or wood. Since there's no way to mechanically secure deck part, we'll glue/caulk it together also. To save more, we can make the deck (floor) portion of deck cap light also and support underneath with more foam. more
Ever been to a boat show, walked on a spongy deck, while your wife/GF/ho commented how she liked the "shiney sides" inside? Probably 2 piece hull.
Most all NC boats are 3 piece hulls including Regulator, MayCraft, Privateer, C-Hawk, Albemarle, Carolina Classic and of course, PARKER.
Advantages,
You can walk to the gunnels without stubbing toes.
Solid decks that don't bounce.
Access to vitals w/o those silly 6" access covers everywhere.
Foam is used for flotation, not as a structural compotent.
Hull is generally heavier and doesn't relie on hull liner for support.
It is very hard to ever find a gel-coat crack in a Parker.
Well, that's enough for now. Sorry you ask?
Whoops, almost forgot. Three piece hull makes it easier to install whatever kind of transducer you like. I really like my Airmar Tilted Element. Since the hull is solid fiberglass, install is quick and easy.