Attwood Marine Sahara S500 Automatic Bilge Pump, 12V, 500 GPH, 3/4 in Outlet

Overview

The Attwood Marine 4505-7 is an automatic 12V Sahara S500 bilge pump rated at 500 GPH at open flow and 350 GPH at 3.3 feet of head, with a 3/4 inch discharge outlet. It combines the pump and automatic switch in one body, which keeps installation simpler in tight bilge spaces and avoids the extra footprint of a separate float switch.

This is a practical fit for boats that need unattended bilge water removal while sitting at the dock, on a mooring, or between trips. It is meant to clear standing bilge water, not fuel, oil, or fast flooding from hull damage or heavy weather.

Key features

• Automatic pump with an integrated mercury-free switch, so the unit can cycle on when water rises without a separate float switch.
• 12V output rated at 500 GPH at open flow and 350 GPH at 3.3 feet of head, which gives a clearer picture of installed performance.
• Fits a 3/4 inch I.D. discharge hose, which matters when matching an existing hose run or thru-hull size.
• Uses 16-gauge tinned copper leads and calls for a 2 amp fuse, which helps when planning the wiring run and switch panel connection.
• Permanent-magnet motor, stainless steel shaft, steel-reinforced seal, and a strainer base that can be removed for cleaning.

Installation and setup

Mount the pump in the lowest flat part of the bilge with the outlet pointing toward the transom and the discharge nozzle kept level. The hose should rise steadily to the thru-hull without dips, since trapped water or air in the line can cause airlock and cut pumping performance.

The pump body is sealed and submersible, but the wire connections should stay out of the water and be sealed properly. For a standard helm-controlled circuit, install it with an inline fuse and an AUTO/OFF/MANUAL switch.

Compatibility and fit

This pump makes sense on 12V boats already set up for a 3/4 inch bilge discharge hose, especially where space is limited and a combined pump-and-switch layout is easier to place. It also works well as a secondary automatic pump in a stepped bilge, fish box sump, or other low point where you want backup water removal without adding another float switch.

Use on board

It suits owners who want a simple automatic bilge pump for runabouts, small center consoles, aluminum fishing boats, and sailboats with a modest bilge area. On larger boats, it is more often used as a secondary pump or for a smaller compartment rather than the main high-capacity bilge circuit.

Shipping
We ship worldwide from the United States. Rates are calculated at checkout based on destination and package weight. Some items include free shipping, which will show automatically. Not every product is eligible for international shipping; checkout will confirm eligibility. We do not ship to PO Boxes except through USPS, and not all packages qualify.

Processing and dispatch
Most orders are verified, packed, and handed to the carrier within 1 to 2 business days. Some products may need extra handling time or ship directly from the manufacturer. For certain international orders, inventory transfers between warehouses may add time. If any delay is expected, we will let you know the dispatch date.

Delivery and tracking
Deliveries are handled by trusted carriers such as USPS, UPS, FedEx, and DHL. Estimated arrival times appear at checkout and depend on your location and the service you choose. These are estimates and can be affected by customs or carrier disruptions. A shipping confirmation with a tracking link is emailed when your order ships, and tracking may take up to 24 hours to update. You can also view tracking in your account.

Duties, taxes, and support
International customers are responsible for any customs duties, taxes, and fees charged by the destination country. If these charges are refused and a shipment returns to us, the carrier’s return cost and any re-entry customs fees will be deducted from the refund. If your order is late or you need help, contact cs@qualityboatparts.com and we will assist you.

Quality Boat Parts is a reseller. Many items include a manufacturer’s warranty, and all warranty service is handled directly by the manufacturer. We do not manage or administer warranty claims on behalf of customers.

Warranty terms, coverage, and duration are set by each manufacturer. Issues involving defects, repairs, or replacements must be addressed with the manufacturer’s support team. When available, the warranty period is listed on the product page. If it is not shown, contact us or the manufacturer for details before purchasing.

To start a claim, the customer must contact the manufacturer and follow their process. Keep your proof of purchase and original packaging, and register the product if the manufacturer requires it, as these are often needed for warranty service.

We are happy to help you find the right contact or documentation, but we cannot decide outcomes or intervene in claim resolutions. For guidance, email cs@qualityboatparts.com.