Engineer's Page

This is the page where you can ask our resident technical wizard, Clive, any engineering questions you may have. Please email clive@kingsground.co.uk

Macerator Toilet Maintenance (17-12-08 )

Clive's Top Tip: Manufacturers advise of a white vinegar treatment twice a year to maintain your macerator toilet, I would suggest that livaboards should descale every couple of months at least.
 
Question for Clive

Dear Clive,
 
I hope you are keeping well! Could I trouble you over a couple of things?
 
In view of my technical inability I subscribe to RCR. They offer a free annual check as part of their insurance. Their engineer came on Saturday and was surprised that there was not a flexible coupling round the prop shaft. I hope I have got this right. He wondered if that had something to do with the liquid stern gland. I glazed over at this point- Do I need one?
Both this engineer and my local boatyard have been unable to solve a problem with the bowthrusters. They had been working perfectly until a couple of weeks ago. Now there is no green light appearing on the control when it is switched on. Both engineers have said that the batteries are well charged and there is no fault with the fuses at the ‘bow thrusters’ end. Who should I get to come out to look at this?

Clive replies:
 
In answer to your questions;
 
This observation has arisen before from similar engineering sources, can’t nock that, they have a vast knowledge of general practices but it comes under the heading ‘if it works use it’, however, that’s the quick answer! Truth is, as you are aware in the narrowboat world different people have different ideas so here is the history behind it. Prior to adopting our current practice of using a water lubricated stern bearing we were fitting a standard bearing and stuffing box, along with a Centra flexible coupling, mainly to our preferred Beta propulsion units, that was fine except that over the course of time two factors came to our attention. With engines getting quieter problems with propeller/shaft noise, a real problem to cure! And the view that eventually grease lubricated stern tubes would be frowned upon on environmental basis. I had been asked by a very trusted source to try the Vetus stern gear used so we ran the set up past Beta marine and fitted the first back in Dec 04. (30 craft since) I think its important to point out that each installation should be looked at individually, the same set up on an alternative engine unit may not work, the Beta 43 is a particularly steady unit, other engines move too much, so basically we have a engine on substantial flexible feet, aligned as accurately as possible when static with rigid ½ coupling to a 30 mm stainless shaft which is slightly flexible in itself, the water lubricated stern bearing which I believe reduces noise transmitted by direct mechanical contact of conventional stern gear and a quality propeller, normally a Vetus manufactured item. I have to say that so far I have been very happy with the performance, thinking on, we have recently done a couple with 35 mm shaft on 3:1 reduction and that also works, the bigger prop gives better low rpm performance.
 
More than happy for you to pass this on to RCR and hope they will accept my justifications. My personal view is often simplest is best, over the years I have seen a lot of problems created by over engineered stern gear assemblies!
 
Bow Thruster, It’s a BCS 85 unit, I suppose the most common failure after the battery is the control panel, it should be a fairly simple matter to test, myself I’d either use a jump lead at the forward end, or I have been known to unplug the control aft and try plugging it in forward!  Once establishing where the fault lies parts are available from Aquafax. Can we be of assistance, where are you moored? We have a man with a van!