Attwood Marine Sahara S1100 Automatic Bilge Pump, 12V, 1100 GPH, 1-1/8 in Outlet

Overview

The Attwood Marine 4511-7 is an automatic 12V bilge pump for boats that need the bilge cleared without constant manual checking. It is rated at 1100 GPH at 13.6 volts in open flow, uses a 1-1/8 inch I.D. discharge hose, and reaches a maximum head of 11 feet at design voltage.

This is the Sahara S1100 size, with a compact housing that fits low in the bilge where space is limited. The body measures about 5-1/2 inches long, 3-1/4 inches wide, and 4 inches high, and the automatic switch is built into the pump so there is no separate float switch to mount.

For day boats, cruisers, and other vessels that stay in the water or collect rainwater at the dock, this pump covers the basic job of moving standing bilge water before it becomes a bigger problem. It is not meant for fuel, oil, or fast flooding caused by hull damage or heavy seas.

Key features

• Automatic operation with an integrated mercury-free switch and a test knob on the pump for quick function checks.
• 12V output rated at 1100 GPH in open flow, about 973 GPH at 3.3 feet of head, and about 750 GPH at 6.7 feet of head.
• Fits a 1-1/8 inch I.D. hose and uses a 6-amp fuse for the 12V S1100 setup.
• Compact pump body at about 5-1/2 inches by 3-1/4 inches by 4 inches for tighter bilge compartments.
• Sealed pump body that is submersible, with wire connections that should stay above the waterline and be made waterproof.
• Serviceable strainer base and impeller access, plus a 316 stainless steel motor shaft for better corrosion resistance in marine use.

Installation and setup

This pump is mounted at the lowest practical point in the bilge on a flat, level surface. For correct operation, the outlet is set toward the transom and kept level, and the float end of the pump is positioned toward the bow. A through-hull fitting, hose, fuse holder, switch, fasteners, and waterproof electrical connectors are selected separately to match the installation.

Because this is a 12V automatic pump with built-in switching, it suits boats that need everyday bilge protection without adding a separate float switch. It is a sensible fit for owners working with a tight bilge layout and a standard 12V DC system.

Compatibility and fit

Before ordering, check that your boat uses a 12V DC bilge circuit, has room for the pump footprint, and is already set up for or can accept a 1-1/8 inch discharge line. This model is best matched to installations where a larger automatic pump is needed but access is still limited.

On board, the most relevant checks are hose size, available mounting space, fuse sizing, and how the discharge run is routed to the through-hull. Keeping the hose run smooth and avoiding unnecessary dips helps the pump move water as intended.

What’s included

• Automatic bilge pump
• Integrated mercury-free switch
• Strainer base
• Wire seals