Marine AL-A4 HEAVY DUTY ALUMINUM DOCK AND PONTOON BOARDING LADDER. Aluminum boat boarding ladder with 4 strong, aluminum steps. Easily board your boat with these 4 step boat ladders, each boat ladder extends 48" below your boat's deck. These are the widest boarding steps available on any boat ladder. (5 1/2" depth x 16" width per step) Tall aluminum hand rails make boarding your boat easier and more comfortable. Each boat ladder comes with quick release ladder mounting hardware. Supports up to 350 pounds. Mounting hardware with everything you need is included.