Barrus launch next-generation engines for commercial users

Published on: 30/10/2016

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For years, the Special Products division has worked closely with UK professional rescue organisations as both suppliers and consultants to ensure the teams are reliably equipped to face the most challenging conditions.

This was first demonstrated in the late 1970s when Barrus began working on the development of the Post Immersion Restart System (PIRS®), a system dedicated to the RNLI and armed services. PIRS® drains water from the engine allowing it to rapidly restart after submersion as, when a boat is capsized, the outboard engine becomes flooded making it inoperable and the crew vulnerable. To remove water from the engine and enable it to restart, the engine and fuel system must be drained which is both time consuming and difficult, particularly with the boat moving in the water as components are easily dropped and lost.

The first generation of PIRS® utilised a drain system fitted in line with the carburettor bowls to drain the fuel without removing components. This system proved to be very effective and soon became essential for engines fitted to rescue crafts. However, as the crew were required to remove the spark plugs, feedback suggested that a new method was required.

FAST PIRS®, an improved version of the system, was designed and produced in 2004 and included fuel drains, in addition, to drain valves for transfer ports and cylinder heads which allowed the evacuation of water without removing any components. FAST PIRS® made it possible for an outboard that had been submerged to be restarted in forty seconds and the system was operated by a single lever on the outside of the engine without removing the engine cover.

Initially exclusive to manual start engines, in 2009, Barrus further developed FAST PIRS® and created the fully waterproof, electric start FAST PIRS® which, with the addition of a starter motor, forced water out quicker and reduced restart time to less than 30 seconds.

The Special Products team has now developed two new versions of PIRS®, GEN 2 FAST PIRS®, a simplified, more durable and cost-effective FAST PIRS® system and Capsize PIRS®, a four-stroke adaptation.


Similar to previous FAST PIRS® versions, GEN 2 FAST PIRS® drains the fuel system, but instead of using a single lever to control the system, all valves are operated independently to allow fine adjustment. This latest evolution has proved to be more reliable as the cylinder head valve design is more durable and cost-effective to produce and is fail-safe in operation.

Capsize PIRS® - Four-Stroke

With the combination of environmental concern, the durability of two-stroke engines and customer demand, Barrus launched the four-stroke PIRS® project in 2015 and has now developed a patented system for Mercury and Mariner four-stroke engines. Capsize PIRS® is fully automatic and integrated within the engine’s electronic control unit. The system ensures no water can enter the internals of the engine and is operated without removing the engine cover as, unlike a two-stroke engine, this can contaminate the oil and can cause serious component failure.


The Gen 2 FAST PIRS® system is already being used by commercial and military customers, and orders are in the pipeline for the Capsize PIRS® engines to be supplied later this year.

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