Link to the catalogue • Items 1162 - 3162 - 1163 - 3163
🔗 PDF datasheet water strainer Mediterraneo series
The Mediterraneo strainer is a Guidi design patented in 1982, refined over the years while keeping the same basic layout: a straight-through strainer built to protect engines, generators and onboard systems from the impurities carried by seawater.
Models
With polycarbonate cover:
- 1162, bronze
- 3162, black anodised aluminium
With metal cover:
- 1163, bronze
- 3163, black anodised aluminium
Applications
The Mediterraneo strainer is the right choice when the water flow runs straight, side to side. It filters incoming water and delivers clean water to engine heat exchangers, generators and air-conditioning systems. In marine use it is typically installed in the engine room of pleasure and commercial vessels; it is also used in swimming-pool systems, quarries and drinking-water supply.
It is not suitable as a pre-filter for the fuel circuit.
Cover selection follows the approval class of the vessel. Similar plastic or metal strainers are available on the market, but without the performance characteristics of genuine Guidi products.
Materials
Bronze offers the best resistance to corrosion. To reduce corrosion risk, the whole installation, from the sea inlet to the valve, the fittings and the through-hull discharges, should be made in bronze only, without mixing different materials.
Aluminium is used when the installation needs to be lighter. The same rule applies: do not mix materials, to avoid galvanic corrosion.
Design and hydraulic characteristics
The characteristic lower rounding of the Mediterraneo body reduces pressure loss at the outlet, optimises water flow and limits bubble formation. For best performance we recommend pairing the strainer with Guidi water intakes items 1112B, 1113B, 1260, 1260A, 1261, 1262, also patented.
The whole circuit is designed to reduce pressure loss and limit bubbles and cavitation. Cavitation is the formation of vacuum or vapour pockets inside the fluid, caused by pressure changes. When these bubbles collapse they generate high-pressure micro-jets: the phenomenon produces noise, mechanical damage and loss of efficiency, and over time it can pit any metal surface.
Covers
Polycarbonate cover
The polycarbonate cover suits yachts and civil installations where visual inspection of the inside of the body is required. The material is Lexan, a polycarbonate resin resistant to impact and temperature changes, with good elasticity and resistance to cuts and penetration. For extreme conditions, such as the Polar Circle, a metal cover is preferable.
Metal cover
The metal cover is intended for professional and commercial vessels.
Closure
Covers are opened and closed with hex-head screws, using standard tooling. Screws and washers must be tightened correctly together with the retaining ring and disc (polycarbonate-cover version) or with the cover itself (bronze or aluminium version) onto the strainer body.
Indicative screw tightening torque:
- sizes 3/8″-1/2″: approximately 4 Nm
- sizes 3/4″-1″1/2: approximately 6 Nm
- sizes 2″-4″: approximately 9 Nm
Baskets
The baskets are made of 316L steel, suitable for seawater and marine applications. It is a standard stainless steel with a stainlessness index (PREN) between 25 and 28. Compared with steels such as 304, 316L offers better resistance to electrolytic corrosion: its carbon content stays below 0.035%, against a figure that can reach 0.080% in standard 316.
If the basket shows signs of corrosion, the problem is usually not the material but the installation: the basket has become the sacrificial anode. In these cases, cathodic protection and grounding should be checked.
Gaskets
The Mediterraneo strainer has one O-ring sealing the cover and one sealing the drain plug. Both are neoprene, a synthetic rubber resistant to seawater.
Drain hole
The drain hole is used to empty residual water from the body when the sea-intake valves are closed or the boat is hauled out. It is opened with a wrench or hex-socket key.
Sizing
Strainer size should match the hydraulic system, the engines served and the number of circuits a single strainer has to cover, respecting the pressure-loss data. Strainers should not be oversized.
Inspection and testing
Materials are checked before machining. During production, strainers undergo dimensional, assembly and packaging checks. At the end of the process, every unit passes an air pressure-tightness test.
The hydrostatic test uses a pressurised water-oil emulsion, held for a set time under internal quality procedures, checking for leaks. This test is carried out under the supervision of external laboratories. The water-oil emulsion comes from recycled machinery cooling water before disposal; its white colour makes leaks easier to spot.
The air test pressurises the inside of the strainer body to a set value and checks for any pressure drop. It is fast, efficient and keeps the parts clean. An internal quality certificate is issued for this test, since it is not supervised by an external body, although it still follows certified quality procedures.
RINA and Lloyd’s Register approval
Type approvals certify that a Guidi product has been designed, built and tested in compliance with the rules and criteria of the Italian Naval Register and Lloyd’s Register, themselves aligned with the principles of the international maritime organisation. Approvals require periodic checks to remain valid.
Durability and recyclability
Guidi products are designed for a long and sustainable life cycle: each strainer keeps the physical and mechanical properties of its materials over time, with minimal routine maintenance. Easy disassembly allows individual components to be replaced without changing the whole strainer, extending material life beyond the working life of single parts. At the end of its life, the strainer is almost entirely recyclable through processes that recover raw materials for reuse.
Differences from other Guidi strainers
The Ionio strainer has a different shape and a different water flow path: in the Mediterraneo, flow runs straight from side to side, while in the Ionio water enters from the bottom and turns to the side.
The Tirreno strainer is made in nickel-plated brass or in bronze (the Mediterraneo and Ionio are only available in bronze and aluminium). It is smaller, the compact version of the Ionio, designed for small engines and generators where onboard space is limited. Its cover closure is also different.
Pressure losses
Pressure loss is the drop in pressure caused by resistance and friction the fluid meets along the circuit. Knowing this value is needed to size the piping correctly and to define the characteristics of the equipment that keeps the fluid moving.
Losses are continuous when they occur along straight sections, and localised when caused by elements that change the direction or the cross-section of flow, such as reductions, fittings, valves or strainers.
Installation
Water flow direction is fixed and must always follow the marked arrows. Mounting feet should be anchored down, keeping the strainer horizontal, without changing its position. The chosen position must allow the basket to be removed for servicing.
Once installed, the strainer must be grounded to prevent the basket from being affected by galvanic current: if the installation is poorly designed or built, the basket risks acting as the anode.
We always recommend installing the strainer above the waterline, also as a passive safety measure, for example in case the cover is not properly closed after maintenance.
On a newly installed system, after a few hours of operation the basket should be inspected for any residue from new piping, and cleaned if necessary.
Maintenance and spare parts
Always use genuine spare parts. These are available from the Guidi website or by contacting the company directly: strainer cover ring, strainer cover, 316L stainless steel basket, transparent polycarbonate cover disc, bronze drain plug with neoprene O-ring.
Nuts can also be sourced aftermarket, but must be austenitic A4 low-carbon stainless steel.
Covers are also available as spare parts. They should be replaced in case of leaks, ageing, or loss of transparency due to a chemical spill. Whenever the cover is replaced, the O-ring should be replaced too. Note that changing the cover means moving from one approval to another (see Covers section).
During maintenance or cleaning, always remember to close the cover before reopening the sea-intake valves: otherwise there is a serious risk of sinking the boat, especially if the strainer is installed below the waterline.
Basket replacement requires little experience, but must always be carried out safely, with the sea-intake valves closed. The basket should be checked periodically: if it is too dirty or encrusted, strainer performance drops. It is not only marine fouling that dirties it: debris and plastics carried by seawater can also block the openings of the filtering element. The basket is cleaned with water and compressed air.
With the engine off and the valves closed, access the basket, wash it, and if needed scrape encrusted areas with a suitable tool before repositioning it. Gaskets should be checked and, if worn or in doubt, replaced with genuine parts only.
Before restarting the circuit, check that the screws and washers are correctly tightened together with the ring and disc (1162-3162) or with the cover (1163-3163) onto the strainer body, following the torque values given in the Covers section. Only then reopen the sea-intake valves.
The antifouling kit
The antifouling kit was developed by Guidi in cooperation with Tecnoseal to address the problem of encrustation. Like other purpose-built products, it responds to market demand, particularly strong in geographical areas most exposed to biofouling.
It has two objectives: eliminating the proliferation of marine fouling inside the boat’s seawater circuit, and reducing maintenance while making it easier to carry out. The operation and characteristics of the kit are described in a dedicated brochure.