Do you have a Thru Hull and piping that looks like this? 

  Battery Terminal have limits on how many connections can be on any one post. No more Than 4. Need more? Have a qualified Marine electrician add a proper +/- bar. Why? Excessive overload, Spark, and Fire hazards. Its also a CFR for all vessels.  

 Hose Clamps are available in varying price ranges and quality. What do your hose clamps look like? 

Cracks in the laminate can cause problems especially in cold climates where it can freeze and expand. 

Batteries Need-securing, in a Box or tray to contain any corrosive liquids, the Positive Terminals need to be covered; Wing nuts are not allowed on wire sizes #6 and Larger.

Notice the Orange Wire Nut? That is great in a house but NOT EVER on any boat, vessel or yacht.