Left to my own devices I could happily be a lazy guy, but that’s by no means a good thing to be when you’re in charge of a boat. When running charter boats that are in daily use, daily, weekly and monthly maintenance check lists are absolutely de rigeur to ensure that, random mechanical failure apart, the boat (and most particularly the engine) functions effectively.
There’s no consequential loss insurance available in this regard – blow the engine up through simple carelessness and that’s you out of the game. And it’s even more important when you’re in out of the way places.
So every day I check the oil level, water level, raw water filter strainer and belt tension, and have a good look around under the engine for any signs of leaks or stray nuts and bolts. This simple detective work has saved me endless hours of grief, through nipping many an impending catastrophe in the bud. And every time we start the engine, we check that the exhaust is pumping cooling water – just in case.
With Good Reason
This is especially important in polluted harbours and rivers, where there’s any amount of plastic debris ready and waiting to block your water cooling system. Some of the harbours here in Brazil are the worst I’ve ever seen for rubbish in the water, Salvador and Rio standing out in particular. When entering or leaving such places under power we’ll usually have one of us on rubbish watch, and work our way around any particularly bad patches.
A few weeks ago during one of my daily checks, I noticed that the level of water in the sea water strainer was lower than usual. This could have been caused by a number of factors, including an air leak at the seal on the strainer, a blockage in the inlet pipe (possibly barnacles or other growth), or a failing raw water impeller. So I stripped the lid from the strainer, cleaned it thoroughly and lubricated the neoprene seal.
Next job was to dive under the hull with a screwdriver and check the inlet pipe was clear (it was). A quick run of the engine indicated some improvement, so we decided to give it a few hours test run before checking the impeller, as it had only 200 hours running time on it.
After a few hours running, I checked the water level in the strainer once more, and it still didn’t seem right, so it was time to check the impeller. This has been made easy on Pèlerin by the installation of a Speedseal Easy Slider cover in place of the standard unit. These simple units are essential equipment in my view, and I’ve installed one on every boat I’ve ever owned. Replacing the standard cover with its fiddly (and easily dropped and lost) screws and the vulnerable gasket with four knurled hand screws and an inset O ring means that the cover can be removed, the impeller replaced and the cover back on in minutes, maybe vital minutes – in theory, at least.
In fact, there’s more to it than that to make the most of this useful item. Any new impeller should have the shaft lubricated at installation to stop it becoming stuck to the shaft, as well as the blades to stop them sticking to the pump body at first start up. Volvo supply a little tube of glycerine to do this with each new impeller, and Speedseal supply tubes of a silicone based lubricant to do the same job. Doing this alone will make life far easier at the next impeller change, and extend the life of the impeller.
Otherwise you’ll be trying to prise out the impeller with all manner of potentially damaging weapons, like a pair of screwdrivers – if the old impeller is stuck on the pump shaft that’s the sort of last resort solution you’ll have to reach for. But, if the impeller was in fact OK, then it certainly won’t be OK any more, and if you damage the soft metal of the pump flange, you may well have problems with leaks in the future. Many years ago I bought a proper Jabsco impeller puller, which has proved invaluable ever since, not just on our boat, but on loan to others. They don’t cost much and are easily available, and you’ll never risk mangling the pump flange or an impeller again.
And The Impeller?
In the pump it looked fine, but you really can’t tell until they’re on the bench in front of you for proper examination. Once I could get a good close look, it was clear that the impeller was on its way out. The blades had taken on a permanent curve in the direction of rotation, and there were cracks on at least two of the blades – time for a new one.
Perhaps the amount of time we’ve spent up rivers and in dirty harbours had proved too much for it, as I’ve known these impellers to last for years if looked after and removed and lubricated during winter lay-up. But this experience has convinced me that it’s false economy to keep an impeller in use for longer than a year, and in future we’ll install a new one on an annual basis.
So we dug into the engine spares locker for a new impeller (we always carry at least three spares) and O ring, cleaned the pump face and the Speedseal cover and lubricated the pump shaft and the new impeller.
If you’ve ever struggled with installing a new impeller in this type of pump, this can be made easy by bending the blades into the correct plane of rotation and then tightening a cable tie around them to keep them compressed, then tap the impeller gently into place – done like this it’s simplicity itself. On with the cover, open the seacock , start the engine – result? Perfect – water level correct in the strainer, and a noticeable improvement in pump volume at the exhaust.
If a Job’s Easy, You’ll Do It
Far too often we put jobs off because they’re tricky or messy – the old adage that ‘if it ain’t broke, don’t fix it’ always surfaces at such times. But make it simple and quick, and there’s no excuse for inaction, and the simple actions suggested here will make this job a breeze, without breaking the bank. And check, check, and check again!