Marine Pump Specification for Superyacht Refits: A Procurement Buyer's Guide

Why Pump Specification Matters in a Refit

Marine pump specification is one of the easiest places to leak budget on a refit, and one of the hardest to recover from once the wrong unit is installed. A pressure pump that costs EUR 180 instead of EUR 480 looks like a saving on the day the PO closes. Three charter seasons later, when it's been replaced twice, taken out a week of bookings during a Mediterranean July, and stranded a client in flat calm with no shower water, the maths look different.

The OEM-bundled pump fitted to a 1990s or early 2000s Beneteau, Sunseeker, or Princess wasn't specced for a commercial charter operation. It was specced to hit a build price. For a private owner doing 80 engine hours a year, that's fine. For a charter yacht running 600+ hours over a Med season with daily turnover and back-to-back bookings, the same pump is running 7-8x harder in salt-air conditions the original spec sheet never contemplated.

This guide is written for the procurement side of a refit decision: chief engineers writing the spec, project managers approving the line items, and fleet managers standardising kit across multiple yachts. It walks through pump categories, the lifecycle cost case for bronze, voltage decisions, and the specific Gianneschi units we recommend for typical Mediterranean refit briefs.

Pump Categories and What Each One Does

Yacht pumps split into four functional categories. Each one has spec criteria that actually matter, and a long list of spec criteria that don't. Knowing which is which is half the procurement job.

Pressure Systems and Autoclaves

Packaged units that pressurise the fresh-water circuit for taps, showers, and galley sinks. They combine a pump, a small accumulator tank (typically 8-20 L), a pressure switch, and a check valve in one bolt-down assembly. The Gianneschi Idromini and Idro-Ecoinox families sit here. Spec criteria that matter: tank capacity, cut-in/cut-out pressure range, port size, and voltage. Spec criteria that get oversold: maximum head (irrelevant for fresh-water service inside a yacht), and brand-specific accumulator sizing fluff.

Self-Priming Centrifugal Pumps

Standalone pumps for transfer duties: diesel, lube oil, fresh water, sea water, washdown, and standby fire. The Gianneschi CP20 and CP30 sit here. The defining spec is suction lift (how far below the pump the source liquid can be) and flow rate at working head. The CP30 24V delivers 90 l/min with 8 m of self-priming lift, which covers diesel transfer from a wing tank, anchor-chain washdown from a sea chest two decks down, or grey-water pump-out from a sump.

Multi-Use Electropumps

One pump assigned to several jobs through a manual valve manifold. The Gianneschi ACB Electropump 24V is the archetype: 50 l/min, 3.4 bar, 8 m suction lift, bronze body. On a 35-50 ft cruiser, one ACB unit can be plumbed for anchor wash, bilge, fire, fresh-water transfer, and diesel transfer through a five-port manifold. Cost is roughly EUR 600 versus the EUR 1,400+ you'd spend on five dedicated pumps. The trade-off is that you can only do one job at a time, which is fine on a private cruiser and unacceptable on a commercial charter platform.

Macerator Pumps

Black-water and grey-water tank pump-out. Different mechanical design (screw rotor with a stator, not a centrifugal impeller) because they need to pass solids without seizing. The Gianneschi MV44G 24V handles 25 l/min at working pressure, 50 l/min maximum, with 4 m self-priming lift. Spec criteria that matter: voltage, port size to match the tank manifold, and material compatibility with disinfectant chemistries used in the holding tank. Anything else is noise.

Bronze vs Plastic vs Cast Iron: The Lifecycle Cost Case

The single biggest specification decision is body material. It's also the one most often made on the day-one purchase price.

Plastic-Housed Pumps

Jabsco Par-Max, Shurflo, and Flojet are the three names that dominate this segment. They're cheap (EUR 120-280 for a typical pressure unit), they're light, and they're stocked in every chandlery from Palma to Antalya. They're also wrong for a commercial refit. UV exposure through engine-bay ventilation, salt-air heat cycling, and chemical attack from cleaning agents typically take the housing out at 24-36 months in Mediterranean service. The motor's still fine. The pump still spins. But the diaphragm housing has crazed, the pressure switch mount has cracked, and water is weeping past the casing seam. You replace the unit because there's no way to repair the body.

Cast Iron Pumps

Common in older industrial-derivative pumps still found on workboats and some commercial conversions. Cast iron corrodes in salt-air engine bays, and the corrosion is galvanic when bolted to bronze through-hulls or stainless brackets. Visible rust within the first season, structural failure within five. Don't spec cast iron in a marine refit unless the application is genuinely freshwater-only and topside.

Bronze Body with 316 Stainless Shaft

The Gianneschi standard spec across the CP, ACB, Idromini, and Ecoinox ranges. Bronze body, brass impeller (or marine bronze in the heavier CP30), 316 stainless shaft, NBR or Viton seals depending on duty. Service life under continuous Mediterranean charter use is typically 15-20 years with periodic seal and impeller refresh every 3-5 years. The unit is rebuildable: every wear part is sold as a service kit.

10-Year Cost of Ownership

Honest numbers, not marketing. For a representative pressure pump on a 50 ft motor yacht in commercial charter use:

The bronze unit is 2.6x the upfront price and pays back by year four, ignoring the charter revenue protection entirely. Once you price in the cost of a cancelled day at EUR 8,000-15,000 charter revenue, the comparison stops being interesting.

Voltage Decisions for Different Yacht Classes

The right voltage is the one that matches the yacht's house bank, not the one that's cheapest off the shelf. Mixing voltages adds DC-DC converters, which add failure points, heat, and spec sheet drama at survey time.

12V Systems

Sailing yachts under 35 ft on a single house bank still run 12V. Hallberg-Rassy 31s, older Bavaria Cruiser 32s, smaller Jeanneau Sun Odyssey hulls. The Gianneschi Idromini ACB 12V is the right call for these. 12V draw matches the bank, no converter required.

24V Systems

The default for modern bluewater cruisers 40 ft and up, all motor yachts above 40 ft, and almost every superyacht tender. Lower current draw for the same power means thinner cable runs, smaller breakers, and less voltage drop on long fresh-water circuits. The bulk of the Gianneschi range is 24V for this reason: Idromini Ecojet 2B 24V (22 A draw at 0.37 kW), CP30 24V (28 A at 0.45 kW), ACB 24V (0.44 kW).

230V AC Systems

Yachts with permanent shore power or a genset on autostart. Charter yachts that sit dockside between bookings, commercial workboats, and any vessel where the genset runs whenever the pump runs. The Idro-Ecoinox 2 230V is the AC version of the same pump platform, and it's the right call when the DC bus would otherwise have to size up just to feed pump loads.

400V Three-Phase

Engine-room ballast pumps, fixed firefighting systems, and high-flow bilge pumps on superyachts above 30 m. Outside the scope of this article, but worth noting that the same Italian manufacturers that build the Gianneschi DC range (and parallel manufacturers like Marco and CEM) cover the 400V three-phase end too. Spec it from the same supplier family and the spares-interchangeability argument extends across the whole vessel.

Procurement implication: spec the voltage that matches the house bank. If you're choosing between a EUR 580 unit in the wrong voltage and a EUR 720 unit in the right voltage, take the EUR 720. The DC-DC converter you'd otherwise need costs more than the difference and introduces a single point of failure for the whole fresh-water system.

Autoclave vs Self-Priming Pump Trade-Offs

This is the question that comes up in every refit kick-off and rarely gets a clean answer. Here's the framework.

Fit a Packaged Autoclave When

The job is one job: pressurised fresh water for taps and showers. The plumbing layout is conventional (tank below the pump, manifold above, no exotic routing). The space allows a single bolt-down unit with the accumulator built in. On a 35-55 ft cruiser this is almost always the right answer. The Idromini Ecojet 2B 24V drops in, plumbs to standard 1" BSP fittings, and runs the whole fresh-water circuit at 1.5-2.8 bar without further engineering.

Fit a Separate Self-Priming Pump Plus Accumulator When

The plumbing is non-standard. Tank position requires more than 4-5 m of suction lift. The fresh-water manifold serves more than three heads plus a galley, where a packaged autoclave's tank capacity becomes the bottleneck. You want to size the accumulator independently for water-hammer reasons. In these cases, a CP20 or CP30 plus a separately-mounted 24 L stainless accumulator gives you the flexibility a packaged unit can't.

Fit Both When

The yacht is bigger than 55 ft and has separate fresh-water and washdown duties that shouldn't share a pump. Standard pattern: an Idromini Ecojet 2B 24V handling galley and heads, a CP30 24V on the deck washdown and anchor-chain manifold, and the two systems plumbed completely separately. This is the configuration we spec on most charter platforms in the 55-80 ft range.

Why Specify a Single Brand Across the Fleet

For a charter management company running 8-15 yachts, or an owner with a cruising fleet of 3+ vessels, single-brand standardisation is the single largest reduction in operational drag we see in pump specification.

• Spares interchangeability. An impeller kit for a CP30 fits any CP30, regardless of the yacht it came off. Bench-stock one of each kit type and you've covered the whole fleet.
• Single training spec. Engineers know the pump. They know the service interval. They know which spanner fits the pressure switch. Onboarding a new technician to a fleet on Gianneschi takes a week. Onboarding to a fleet running mixed Jabsco/Shurflo/Marco/Lowara takes months.
• Volume pricing. Bulk POs on a single brand attract dealer pricing that single-yacht orders never see. Eight units on one PO regularly hits a 12-18% discount versus eight separate orders.
• Warranty handling. One supplier, one RMA process, one freight lane. When a unit fails out of warranty, the same dealer who sold it knows the serial number history.

Mercer's role on fleet specs is to handle the procurement contract: aggregate the demand across the fleet, place the consolidated PO with Gianneschi (or the appropriate Italian distributor), and coordinate Malta-side delivery and Ritz Marine spares stocking. The yachts get their pumps. The fleet manager gets one invoice. The engineering teams get a stocked spares bench they can reach in 90 minutes.

Recommended Gianneschi Range for Typical Refit Briefs

The matrix below is the default we work from. It's not a substitute for a vessel-specific load calculation, but it's the right starting point for 80% of Med refit briefs.

Each linked product page on ritzmarine.com carries the full data sheet, current EUR pricing, and stock status. For fleet POs, contact us directly so the order goes through the procurement contract rather than the retail catalogue.

Parts Availability and After-Sales: The Med Question

The best pump in the world is only useful if a stator kit is in-region when it fails. This is where most Atlantic-headquartered procurement chains break down for Mediterranean fleets. The unit is in California, the spare seal kit is in California, and the yacht is in Bonifacio with charter guests aboard.

Ritz Marine, our parent company, holds Gianneschi spares at the Triq San Antnin showroom in Malta. Service kits, impellers, pressure switches, and complete replacement units for the most common models are stocked locally. Lead time from order to vessel for in-stock items is same-week, often same-day for Malta-based yachts. For non-stocked items, the lead time from Gianneschi's Italian factory to Malta is typically 7-10 working days versus 21-30 days from US-coast distributors.

For non-Gianneschi consumables (Marco hose fittings, Italian-spec accumulator membranes, reverse-osmosis pre-filters that interact with the pump circuit), Mercer's 500+ supplier network handles the sourcing. One PO, one delivery, one invoice, including the bits that aren't on the Gianneschi catalogue but that the engineering team needs in the same shipment.

Specifying Pumps for a Mediterranean Refit?

If you're scoping a refit and pump specification is on the line-item list, the cheapest hour you'll spend on the project is a 30-minute scope review with us before the PO closes. We'll review the existing pump inventory, the duty cycle the yacht actually runs (charter vs private vs commercial), the house bank voltage, and the spares position you want to be in by the start of next season.

Output is a written spec recommendation, a bill of materials, and a delivered-to-Malta price. No retainer, no obligation. If the spec changes nothing, you've still got a defensible second opinion in writing for the project file.

For more on how Mercer handles fleet-side procurement contracts, see our procurement overview. For the full Gianneschi range with current pricing and stock status, see the Gianneschi pumps landing page.