Technical
Read about technical aspects discovered by our members. Note some articles may appear under more than one category.
I recently had to service my fuel level sensor and took the opportunity to measure my diesel fuel tank and fuel sensor characteristics. I also measured the tank level to fuel gauge calibration, the graph below shows the Fuel-gauge reading verses the fuel level. Conclusion -The fuel sensor only starts to register the fuel level when the level reaches 23 Litres of fuel (When the fuel-sensor-float starts to float). This corresponds to the gauge level at the left of the RED band. The gauge rises reasonably linearly until the sensor gets to maximum at 90 Litres (When the float hits the top of the sensor travel), this corresponds to the gauge at the right of the BLUE band. The 1/4, 1/2 and 3/4 positions are equally spaced across the whole of the gauge scale. That is between the left of the RED band to the RIGHT of the BLUE band.
Saildrive rubber gaskets should be replaced every 7 years according to Volvo and involves a fair amount of work to remove the whole saildrive. Derek Gardner has written an excellent article about how he replaced the gasket on his Maxi 1000 which you can find further below.
First, thanks also to Bob Garrett for giving us his own experience…
The two and three bladed folding propellers fitted to Maxi Yachts currently use anodes bolted to the propeller for galvanic protection. Older propellers do not have these anodes and rely on the leg anode for protection. The propeller fitted with anodes is electrically isolated from the propeller shaft, the propeller without anodes is not. Apparently, some rope cutter installations can bridge the electrical insulation between the shaft and the propeller.
We are told that Volvo do not agree to rope cutters being fitted to their props and if you have a new propeller this invalidates the Volvo 3 year warranty. Volvo have stated that all their dealers are instructed to inform owners of this fact.
Hence owners who are contemplating a cutter should discuss it fully with an authorised Volvo dealer who should also undertake the fitting and provide confirmation of warranty.
Note: Saildrives are also electrically isolated from the engine block, at least on later models. Hence it is important to check there is no continuity between the leg and the engine. Do make sure the throttle/forward/reverse controls do not inadvertently short circuit the insulation!
The standard propeller is a LEFT handed 3 bladed 17 pitch x 12 diameter – and not Right as previously informed.
A Maxi 1000 problem I had last year was when the loo stopped working – I blamed others for blocking it, but found eventually that the holding tank was full of limescale – like the pipes get but this time blocking the internal stainless pipes and 8 – 10 mm thick on the side wall of the tank. I took out the tank and chipped and banged away to get it all out – a job worth doing this winter BEFORE IT BLOCKS if boat is 10 years old+
Also there has been a problem with the new PAR Brydon loos – they deleted a spring behind the inlet valve and many paople are having flushing water priming problems. If they are (as we are), they need to get the spring – this will fix it. They will supply it free!
Derek Gardner Oct 2006
Rob Ware, Eye of Horus adds… “We also had a blocked loo this summer and like Derek I initially blamed the crew. It turned out that limescale (up to 8 mm thick) in the hose between the loo and the holding tank had become dislodged and totally blocked the pipe. I ended up replacing the pipe. It is probably worth checking the internal condition of the pipe every couple of years.”
Chris Wildey adds… “I used RydLyme Marine earlier this year when I was getting worried about pipe blockage. It seems to have worked, and there is certainly no limescale in the tank itself after 5 years. It would be interesting to know how others have got on with this or other solutions. www.rydlymemarine.co.uk