The heart of the boat

Initial assessment

A new motor with a sail drive was installed in 2008. It seems OK, but have some problems in details.

Motor viewed from the Saloon with quite a bit of corrosion.

Sail drive

The boat has not been out of the water for years. Yanmar recommends to change the diaphragm of the sail drive every three years. We have no information on whether it was ever changed since 2008 when the motor was replaced.

Fuel pump

There are manual and electric fuel pumps. The manual one is the same as in outboard motor fuel lines, but one has to open the engine compartment to use it. The electric pump seems to be a diaphragm pump, it was controlled by a switch in the control panel. In terms of operation it would make more sense to have the pump switch in the cockpit, ideally at the motor control panel.

Electrical System of the Motor

Motor

There are different types of alternator belts on board (A and B) as spare parts. It appears that the A belt used currently wears quickly. The reason being the pulleys very corroded and covered with abrasive rust particles. There were different spare belts on baord of different sizes, some of them not fitting at all.

To do:

Check which belts fit
Buy seawater pump belt
Buy impeller
Buy alternator belt
De-rust or change pulleys
Come up with a maintenance schedule. Check operating hour meter and install one if broken.
Change sail drive oil and check for water intrusion, if neccessary change o-rings and oil seals of the propeller shaft
Change anodes of the sail drive

Sometimes the motor does not start, the starter motor “does not have power”. It appears that the cause is bad contacts at the starter motor relay because the battery is full.

Note to self: Check wiring and replace corroded connectors.

Additional problems

When sailing to Pandan Island we had several motor problems:

Heavy wear of the belts because the pulleys were very rusty / abrasive
Malfunctioning alternator – empty starter battery, no charge
Clogged fuel lines

Repairs at Pandan Island

Addressing overlooked problems

Martin had made a basic mistake. He had not checked the oil level of the motor before leaving, trusting that it would be all right because the oil was just changed before the All Souls Regatta. When the motor was reved high at a course facing waves at night, the motor was producing some smoke. Checking the oil level showed that it was overfilled. The manual pump for draining the oil was, as so many things on board, unuseable. So improvisation was needed again.

After the maximum level of oil was reached, around one liter had been removed.

Lesson learned: Trust nobody.

Sringe and small tubes to extract motor oil.

Changing the first tank sensor

The instruments for the tank levels were broken. I could not find replacements for the same sensor, so I bought commonly avaialble gauges and the corresponding sensors. The aluminium tank cover needed some modifications because the new sensor requires a bigger hole. Luckily the distances of the 5 screw holes have the same spacing for new and old sensors. I went to work at Mariposa’s workshop with the electric jig saw and a file.

Before fitting the new sensor I calibrated it for specifying the input singal for the Arduino HAL 9002.

Left: Calibration of the resistance of the sensor at different levels.
Right: Cleaned plate with mounted new sensor, new cables and fuel line.

Fuel system

The boat has two diesel tanks. One with 50l and one with 60l capacity. When we purchased the boat only the 50l tank was used, the 60l tank was almost empty. Removing the aluminium cover on the top of the fiberglass tank showed that there were a few liters diesel inside but they were also heavily contaminated with sludge.

Inside of the tank, view through the baffle plate

Sludge removed with the around 5 liters of dirty fuel inside the 60l tank.

No idea what this tube is for. It might have been the original outlet tube. Due to its big diameter it would probably not have clogged.

An improvised new fine steel mesh filter for the outlet tube.

I should have cleaned it with a high pressure cleaner, but in the absence of it I had no choice but to manually clean it. That is nothing you like to do more often. After cleaning the tank, fitting a new filter and fuel lines, and installing a fine wire mesh filter at the tip of the outlet tube, this side of the system was OK. I also needed to change the fuel filter and to bleed the lines. The engine then started immediately and ran well.

Replacing the Alternator

The alternator had given up on our trip to Pandan Island in December 2025.

A survey of various boat supply web pages showed that new replacement alternators cost between US$ 450 and 1,200, plus shipping. SVB in Germany had one for 195 Euro. A quick communication with Willi and Klaudia, who were scheduled to come to Pandan in a few days, led to Plan A: Purchase of a new alternator in Germany, shipped to a German address and hand carrying it to Pandan Island.

Plan B was to get the old generator repaired in a local car electrical workshop in Sablayan. Noel helped me in implementing this. Mathias brought the broken regulator IC from Germany, the shop soldered the old one out and the new one in, and now I have a spare alternator.

All worked out well with Plan A, I fitted the new alternator and we now have the repaired one as spare.

Before fitting the new one I had to wire brush the pulleys on the crankshaft and the water pump. They were totally rusty wearing down the fan belts in record time. After reaching blank metal I treated them with rust converter and primer. The are not abrasive anymore, but probably it would make sense to replace them at some time (after the dry dock).

The saildrive

The boat comes with a Yanmar 3YM30 engine with SD20 SailDrive. Both, as an integral unit, were replaced in 2008, so much younger than the boat itself.

The diaphragm

A critical component of the saildrive is the diaphragm, a large rubber piece, that connects the drive with the hull and prevents water from getting in. Yanmar recommends to change the diaphragm every 3 years. Insurance companies reject to cover boat loss if the change interval is not maintained, not that we would have insurance for the boat (only third party liability), but this is an indicator for the importance of the diaphragm. I would assume that it has not been changed since the motor was installed in 2008. There is also a sensor that triggers an alarm when water leaks beyond the diaphragm, but the motor alarms currently do not work. So I am a bit worried about this.

I checked online, no company that sells sailboat supplies, had the diaphragm. Then I checked with Broadwater Marine, Delivery time for a part ordered from Yanmar is 4 months, WHAT? For a part that is supposed to be critical? I ordered it, just to have it when the opportunity to change it arises.

The Anodes

The other critical parts are the zink anodes. The protect the aluminum and other metals of the SailDrive from corrosion. They should also be changed frequently. They are in really bad shape on the boat since not has not been out of the water for so long. There is actually some corrosion on the SailDrive on the left side, not too serious, but starting.

This needs urgent attention.