Choosing a Marine Transfer Pump
Bilge, sludge, ballast, oil, chemicals, seawater: a vessel moves a lot of different fluids. Here's how to pick a pump that handles them, sizes correctly, and is legal in a hazardous zone.
Why air-operated diaphragm pumps suit ships
The air-operated double-diaphragm (AODD) pump is the workhorse of on-board fluid transfer, and for good reasons that matter at sea. It is driven by the ship's compressed air rather than electricity, so it is simple, and in a stainless ATEX build it can work safely in hazardous areas. It self-primes, will run dry without damage, and stalls under pressure without harm, so a crew member can close a valve, walk away, and the pump simply waits. There is no seal to fail and the wetted path can be specified to suit almost any fluid.
What gets pumped
- Bilge evacuation and sludge out of the cargo area.
- Ballast transfer and dewatering.
- Oil out of barrels and tank emptying or filling.
- Seawater for deck wash-down.
- Chemicals and petroleum liquids: in ATEX stainless builds for hazardous transfer.
Match port and flow to the job
Pick the port size for the hoses and connections you'll actually use, then confirm the flow meets the time you have. Oversizing wastes air; undersizing leaves you pumping all watch.
One family, drum to ballast duty
Diaphragm pumps are chosen by port size and the flow that follows from it. Graco's Husky™ range spans ¼" to 3" with flow up to about 1135 lpm (300 gpm), so a small ½" pump for drum and barrel work sits in the same family as a 3" pump for fast bilge or ballast duty. As a rule of thumb: pick the port size for the hoses and connections you'll actually use, then confirm the flow meets the time you have for the job. Oversizing wastes air; undersizing leaves you pumping all watch.
The fluid decides the internals
Seats, balls and diaphragms come in a range of materials; the right combination depends on what's being moved and whether it's abrasive, aggressive or food-grade. Where the area is classified hazardous, the stainless ATEX models are the ones to quote: tell us the fluid and we'll spec the wetted path with the quote.
| Wetted component | Material options | Typical fit |
|---|---|---|
| Seats & balls | Acetal, PP, stainless, PTFE, Santoprene | Match to fluid chemistry & abrasion |
| Diaphragms | Buna, PTFE, Santoprene | PTFE for aggressive / chemical duty |
| Body / manifold | PP, aluminium, stainless steel | Stainless ATEX for hazardous zones |
When to go electric
Air is convenient but not free: running a pump for hours burns a lot of it. Where air supply is limited or the energy bill matters, an electric diaphragm pump keeps the good behaviour (self-priming, stalls under pressure, long diaphragm life) while cutting energy use sharply. Graco's Husky 1050e does this for general transfer, and the fully-electric QUANTM™ pumps go further: up to 80% less energy than air-operated, with no compressor and ATEX/C1D1 hazardous-location options. For the full trade-off (energy, air demand and total cost, duty by duty), see our guide to electric vs air-operated pumps at sea.
The equipment for this job
Graco's Husky™ AODD pumps cover ¼"–3" transfer in PP, aluminium and ATEX stainless; the Husky 1050e and QUANTM™ electric pumps cut energy where air is short.
Husky pumps → QUANTM electric → All products →
Prefer to talk? Call (+45) 6916 2400 or email tech@sepcotech.com — or send your ShipServ RFQ to TN 317545.
Built around Graco's marine fluid-transfer application notes. Original source: graco.com: AODD pumps for the marine industry. SepcoTech supplies the Graco marine range against ShipServ TN 317545.