There are many very specific requirements for building a dock in a sensitive environmental area. Where the dock crosses wetlands the height has to be at least as high as its width, usually 4ft or a foot taller than the highest plant at peak season. A 5ft tall person has to be able to walk under the dock without bending over at high tide. A float can only be 10'x10'. if there is underwater vegetation, you can't have a floating dock and you're boat must be hoisted in the air. A variety of groups have to approve the dock including the EPA and the Army Corps of Engineers. Finally you build the dock. What constraints limit the boat(s)? None!  What exactly does this mean? I have reviewed this carefully with DEEP and have concluded the following:

1. In a scenario where no float is allowed, the property owner could have a 50' long houseboat 20' wide. That's 1,000 square feet!
2. A huge boat with twin 800hp engines, that draws so much water that the propellers touch bottom, could be used despite the fact that it would destroy underwater vegetation in a large area from its massive sediment plume.
3. While dredging is never approved for residential property, the boat described above could plow its own channel without violating any regulations.
4. The only limit to boat dimensions is whatever the property owner is willing to try. If the bottom is soft mud, the only downside is your boat might get stuck, and you have to wait for the tide to come in. 
5. If a floating dock is allowed, it needs to be designed so that it doesn't sit on the bottom during low tide since this could damage the bottom of a fragile ecosystem. However, it is OK if houseboat ten times bigger than the floating dock sits on the bottom. 
6. You can't get approval to build a house on your dock because housedock would harm the ecosystem. It is ok to keep a huge ecosystem killing houseboat,  at your environmentally safe dock.