“At the last vessel survey, the MCA wanted me to fit a second float switch into the engine room, and instructed a local contractor to carry out the work, without my knowledge. I wasn't happy with that for several reasons. I feel that there are too many things that can go wrong with float switches and that they are difficult to maintain. They’ll work ok on the day of the survey, but it’s a different story 6 months down the line when you really need them to work and they don’t, so I decided to go for a Hydralert instead" says John, The chemicals used nowadays are strong, and eat into plastics and metals. I had heard that Hydralert was a reliable fail safe system and did what it was meant to do. The MCA weren't too pleased that I had exceeded their regulations by fitting a 'failsafe' system as well as a single float switch, and made me re-survey the boat afterwards. However I’m glad that I fitted a Hydralert, because both the float switch alarms have stopped working since the survey was done a year ago, but the Hydralert just keeps on going. Because it self tests you don’t have to wait till the water is coming up through the deck plates to find out your bilge alarm isn’t working. If it fails for any reason, it will tell you long before that happens. I’ve got faith that it will continue to do so, giving us the reliable early detection that is so vitally needed to control a flood"

The Hydralert system was developed in collaboration between Banff and Buchan College, and Ormston Technology of Fraserburgh and Hull, to overcome the well documented drawbacks of conventional bilge alarms, the college survey revealed that there was a 36% failure rate found among traditional float switch alarms.

Ormston Technology's technical director Francis West commented "It was designed to survive the extreme conditions encountered in a fishing boats bilge, where a cocktail of fish debris, various solids, hydraulic fluid, diesel, oil, detergents, and sodium metabisulphide will eat almost any electrical device or metal wiring you put into it . Coupled with the continual extremes of temperature, vibration and shock, it needs to be tough kit to survive in there. The first protective gloves our installing engineers wore dissolved within minutes of coming into contact with the bilge fluid. It can be really nasty stuff. Its little wonder that some crews rarely test their float switches”

When asked about ongoing developments, Mr West said "We have looked at vessels behaviour in different operations, and after consulting skippers, found that particularly when hauling, the boats are pulled stern down, the bilges drain aft, and the bilge alarms activate. This is a dangerous time, when all your attention is required for gear handling operations, and the last thing you want to do is to leave the machinery controls to cancel a screaming alarm that you know is probably not a flood. When asked if we could overcome this, we changed the software in hydralert to make the low level alarm sound a 1 second burst every 15 seconds, and the high level alarm to sound continuously. The marked difference in sound patterns allows differentiation of the alarm conditions, and doesn't necessitate the skipper leaving the controls to cancel the alarm. He knows the bilges have run aft as expected, but the alarm is not too annoying. He can cancel the alarm for a while at his convenience, knowing that hydralert is still active and watching the situation for higher bilge levels.Mr West also added”I am glad that our customers have faith in our products. It is very rewarding to know we have done a good job in developing a product that improves safety and gives adequate warnings that will help to reduce the number of undetected floods on board fishing vessels.” BACK.....

Float switch alarms have several well documented shortcomings