Anyone who has seen an Atlantic righted after a capsize - hopefully only as a demonstration during Open Days - and then seen the engines restart 'on the button' cannot help but be impressed.

Such reliability does not come easily, and the Atlantic's outboard engines are the result of years of development at the Inshore Lifeboat Centre at Cowes.

From 1974 to 1978 the principle was to keep the water away from the electrics and air intakes by sealing the engine hood meticulously and using a valve to close off the air intake during a capsize. Another valve in the exhaust system prevented water finding its way into the cylinders.

However when Evinrude re-designed the electrics for the 1978 model year Cowes staff realised that some components would survive a capsize with no ill effect, and so attention turned to allowing water to enter the hood but waterproofing vulnerable parts. A purpose-made box was made to house the starter solenoid and another for the ignition power pack, rectifier and various connections. A gravity-operated shut-off valve was fitted to the carburettor air box and a simple 'U' tube inside the exhaust replaced the mechanical valve.

Change This arrangement was used until 1984 when Evinrude changed the design of the air box and carburettors.

Taking a fresh look at the problem the team decided that most electrical components would survive immersion if fitted with waterproof connectors.

The sole exception was the starter solenoid, and this was ultimately re-housed in the centre console - away from the engine.

Alternative designs for the air intake valve were explored, including a weighted ball type, but this was eventually considered to be a blind alley.

An interim system re-using the carburettor system from the earlier motor but with the remote starter solenoid sawthe engines through until the Mklll was finalised - now usingasolenoid valve mounted on a purpose-made air box casting and activated by a mercury switch. This had the additional advantage of being easy to test at regular intervals using a test button on the motor casing.

In 1989 Evinrude again re-designed their motors, although fortunately the existing air box and relocated starter solenoid could still be used with some re-design and re-location of other parts.

The problem now was the exhaust, as the new version was no longer big enough to take the internal 'U' tube arrangement.

Accessible Considerable development and testing saw the MKIV in operation - with an external 'U' tube arrangement, which had the advantage of being easily accessible without dismantling the engine. The MKIV lasted until 1997 on the two cylinder 50hp engines.

However when the Atlantic 75 was introduced more power was needed and Evinrude's three cylinder 70hp engines were chosen to provide it.

From 1992 onwards several new ideas were investigated, but the solenoid air shut-off valve proved the best way forward and a modified version of the 50hp air box was developed.

A version of the existing exhaust 'U' tube was also fitted, but in 1995 one of the team suggested that the exhaust system could be modified internally to give the effect of the tube without actually fitting one.

The idea worked, and after extensive testing all motors have been produced to this specification since 1996..