Attwood Bilge Pumps & Float Switch Guide

Choosing a replacement bilge pump involves more than matching its advertised GPH. Check 12V or 24V power, the discharge hose, the amount of lift to the outlet, and whether the pump has its own automatic float. This guide compares Attwood HD electric pumps, Sahara Mk2 automatic models, a separate float switch and a hand-operated option using exact manufacturer part numbers.

Three ways bilge water is pumped

External-control electric HD1700/HD2000 series: a powered pump operated by its installed switch or compatible separate float.

Integrated automatic Sahara Mk2: the compact pump includes its automatic float switch mechanism.

Switch or hand pump A 4201-7 float switch controls a compatible pump; 11596-2 operates by hand and uses no power.

Simplified identification illustrations, not installation or wiring diagrams.

Flow at the boat's actual head. Published pump flow varies with test voltage and vertical lift (head). A longer hose, bends and a higher discharge outlet can reduce delivered water compared with open-flow figures.

Attwood bilge pump and float-switch comparison

MPN	Series / type	Power	Control	Outlet or hose
4730-4	HD1700	12V DC	Electric; external control	1-1/8 in
4760-4	HD2000	12V DC	Electric; external control	1-1/8 in
5508-7	Sahara Mk2 S800	12V DC	Automatic; integrated float	3/4 or 1 in barb
5513-7	Sahara Mk2 S1200	24V DC	Automatic; integrated float	1 or 1-1/8 in barb
4201-7	Automatic float switch	12V or 24V DC	Separate switch; not a pump	No hose outlet
11596-2	Hand-operated bilge pump	Not electric	Manual; no wiring	Supplied 32-in hose

The Sahara Mk2 hose-barb choices are manufacturer-listed for the exact retail models shown. Always confirm the rest of the drainage system.

Bilge pump selection checklist

Read the current pump's MPN and confirm whether the vessel uses 12V or 24V DC.
Measure the hose inside diameter and the vertical lift from the pump to the discharge outlet.
Identify whether automatic switching is integrated or controlled by a separate float switch.
Confirm pump fuse requirements, wiring protection and the switch's maximum current for the exact installation.
Check the pump's mounting footprint and available service clearance; never assume pumps with similar flow class share fittings.

A float switch has its own electrical limits. Attwood 4201-7 is rated up to 12A at 12V or 6A at 24V and has a protective float cover. It is not a bilge pump motor. Follow the manufacturer's wiring and protection instructions.

Attwood marine pump products and photographs

These cards lead to exact NewRVParts listings; complete electric pumps, a float switch and the manual pump are not interchangeable purchase types.

Heavy-duty electric bilge pumps

Attwood's 4730-4 and 4760-4 are 12V pumps with 1-1/8-inch outlets; select by intended performance and exact install dimensions.

Attwood 4730-4 HD1700 marine bilge pump catalog product photograph

Attwood 4730-4 — HD1700Choose HD1700 for an application requiring a 12V heavy-duty pump and 1-1/8-inch hose. An automatic float switch is a separate control, not part of this bare pump.View product and availability

Attwood 4760-4 HD2000 marine bilge pump catalog product photograph

Attwood 4760-4 — HD2000HD2000 uses a 12V supply and 1-1/8-inch hose connection. Check available mounting space and electrical protection before substituting for another heavy-duty model.View product and availability

Sahara Mk2 automatic bilge pumps

The S800 5508-7 is a 12V model; the S1200 5513-7 shown here is 24V. Their hose connections and fuse recommendations differ.

Attwood 5508-7 Sahara Mk2 S800 marine bilge pump catalog product photograph

Attwood 5508-7 — Sahara Mk2 S800An automatic 12V Sahara Mk2 for 3/4- or 1-inch discharge hose. The built-in float senses bilge water, and the cartridge can be serviced without removing the mounting base.View product and availability

Attwood 5513-7 Sahara Mk2 S1200 marine bilge pump catalog product photograph

Attwood 5513-7 — Sahara Mk2 S1200This is the 24V S1200-series Sahara Mk2, not the 12V S800. Select the correct power supply and 1- or 1-1/8-inch hose connection.View product and availability

External automatic float switch

4201-7 can control a compatible pump within its rated current limits. It is not supplied as part of the HD pump listing.

Attwood 4201-7 Automatic float switch float switch catalog product photograph

Attwood 4201-7 — Automatic float switchAdd automatic activation to a compatible externally controlled electric bilge pump. Confirm that the pump's current and fuse arrangement suit the switch ratings.View product and availability

Portable hand bilge pump

11596-2 offers a manual means of water removal in small craft. It is distinct from an installed powered bilge pump.

Attwood 11596-2 Hand-operated bilge pump hand bilge pump catalog product photograph

Attwood 11596-2 — Hand-operated bilge pumpA hand-operated option for removing nuisance water without a battery connection. The 24-inch pump has a supplied hose; it does not replace a permanent powered bilge installation.View product and availability

For model specifications and discharge-flow guidance, consult the Attwood manufacturer product catalog. A bilge pump is intended to remove normal accumulated water, not to compensate for hull damage or unsafe navigation.

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Attwood Marine Bilge Pumps: Sahara Mk2, HD Series & Float Switches