Different Boat Covers

[Roadblock007]

I have a full cover that snaps underneath that's great for hwy and storage, I have a Bimini top that is great for keeping out of the sun while on the water, and I have a snap top that is in 2 separate pieces. One for the bow and one for the rest of the boat. What is the purpose of this snap cover? It doesn't look very water tight. I could see water coming in from sliding down the windshield.

 

[poconojoe]

I think they're called mooring covers. I assume you have a bow rider. I have the same covers and use them while my boat is kept in a slip. My front cover has a pole in the center and there's snaps under the windshield that keep the water deflected. The larger cockpit cover has two poles. These covers work very well if you keep them waterproofed. 303 Products waterproofing works great.
Whichever cover works good for you since you have two. The main thing is to keep the rain and other natural debris out of your boat. I'll bet a cover would help prevent sun fading too. So, it's your choice which (or both) to use.

 

[Roadblock007]

I do have a bowrider. 18.5'. The small cover snaps at the base of the windshield and then comes under the centre windshield. The rear portion of the cover is pretty good at keeping water out. I do have 3 poles, 1 for the bow and 2 for the back. I have noticed that when raining the water runs off of the windshield and then goes right under the front cover between the snaps. It isn't horrible, some is deflected, but it's not water tight. That's for sure.