… for the Max from your sailing!

Engine

Engines, gear train, sail drive and props, plus fuel and engine electrics

Velox-Plus-300x297I keep Lookin Foor Kloos on the Lymington river and for some years have been using Trilux antifoul on the propeller. While this has represented an improvement in fouling just polishing the prop, I was still noticing a significant slow down in performance under motor come the end of the season and some growth of worm when the boat was lifted.

Last season, I was getting the boat ready on the yard and a neighbour was praising the virtues of Velox Plus, an Italian antifoul paint and gave me the remains of his tins of primer and antifoul which I gratefully received and used.

So, how did it perform? I must say that the results have been very positive. I re-launched Lookin Foor Kloos in late March and lifted her on August 20th for a scrub prior to a cross channel race. While the hill was a little slimed which washed off easily, the prop came out brilliant white with no fouling at all. The yard commented that most of the boats lifted had had quite some fouling on the propeller so they were surprised.

Re-launched, the prop. Still appears to have remained clean of foul – I will see what it looks like when lifted again in May.

Details of Velox Plus can be found here at www.marlinpaint.com and is available from Marinescene for £36 for the antifoul and primer.

Volvo MD2030 Exhaust Riser/Elbow

Does your engine suffer from lack of power, unable to obtain maximum revs?

We bought a “pre owned” Maxi 1100 – “Maxi Magic” from SD Marine. Whilst she is a very quick boat under sail, the same could not be said when she was motoring. Having sailed through most of the boats out in Poole Bay, we then suffered the embarrassment of them overtaking us when under power coming back into Poole harbour. Something had to be done to restore our credibility!

We had noticed that we could only get a maximum of 2800 RPM out of the engine under load, where as on our previous boat, a Maxi 34 “Eye of Horus” we could get 3400 RPM. The difference in RPM was initially put down to only having a two bladed fixed prop on the 34 as opposed to the three bladed folding on the 1100 and an extra two tons weight difference. Based on our engine experience with the Maxi 34, I took the opportunity in the autumn to remove/inspect the exhaust riser. Having removed the riser it was no surprise to find that approximately 1/3rd of the inner sleeve (where the raw water mixes with the exhaust gas) had corroded away and the main bore had been reduced from 35mm diameter to 7mm diameter (see photo – just enough to get a pencil through!) by the build up of carbon and salt.

                                         

Inlet-Old unit with pencil sized opening                         New unit with 35mm bore

3 exhaust manifold riser outlet                4 exhaust manifold riser outlet

Outlet-Old unit with corroded water gallery                        New unit

In my opinion there is no point in trying to salvage a riser in this state so it was off to the local Volvo agents for a new one (£160 plus £4 for the gasket). (Looking around the internet I did not find any at a materially better price). If you do try and clean/salvage an exhaust riser be very careful of the inner sleeve/water gallery, as although it may be intact, it will probably be rotten and will break up if any force is applied to it.

5 exhaust manifold riser outside          6 exhaust manifold riser outside

Outside View Old unit does not look so bad from the outside!

Having fitted the new exhaust riser we took her out for a sea trial and at full throttle got 3350 RPM. That should be enough to see off the other boats motoring back into Poole Harbour!

On a more serious note, I would recommend that you check the exhaust riser after say 600/700 engine hours (Maxi Magic had done 1100 hours). I considered getting a stainless steel riser fabricated, however, apart from the estimated cost (£250), talking to other people about their experiences with stainless risers, the sulphur in the exhaust corrodes the stainless and stainless cannot absorb the thermal shock (cold sea water and hot exhaust gas) as well as cast iron. Also when stainless cracks you will get a hole whereas cast iron will tend to weep.

Removing the exhaust hose from the riser is a bit of a chore. I used a blunt screw driver and gradually worked it into the joint, taking care not to tear the rubber pipe, and it took about 30 minutes to release. To make it easier to remove the hose in the future, I wrapped the outlet of the new riser in PTFE tape.

Having checked our fuel consumption, this has improved, and the tiny bit of hunting that we had at tick over has now gone. A job well worth doing.

Rob Ware – Maxi Magic

 

 

GaugeI 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.

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5saildriveout

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…

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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!