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  • Writer's pictureSailing The Dream

The ongoing bow thruster dramas

At the beginning of the 2017 season, or more precisely during our shakedown sail to Gibraltar we had an issue with the mechanical fuse when entering Vilamoura Marina in search of fuel, there were some plastic bags in the water and one got jammed in the bow thruster blades causing the mechanical fuse to break to protect its motor, we then fixed it before the beginning of 2017 season and towards the end of the season we started noticing some systems failed here and there.

At the beginning of the 2018 season, we had our first major fail, on our departure day the bow thruster would not power up although it had worked perfectly fine just days before when doing a systems check prior to departure.

A problem that only got solved when we arrived Gibraltar where we ordered a new control panel after we had identified the problem on our stopover in Vilamoura.

In Vilamoura, we had spent a few hours checking for power and connections at a series of different points in the system, starting at the batteries and moving all the way down to the bow thruster motor and then to the control panel.

The culprit was the control panel at the helm station, the cause of death was 5 years of sun exposure. $$ later problem was solved but the question was on the back of our minds, To bowthrust or not to bowthrust, that is the question.

Bow thruster control panel

Months passed by and we used the bow thruster occasionally while dropping or lifting anchor in some crowded anchorages without big issues but noticing that the performance of the thruster was reducing.

Midseason we had a thunderstorm on an already overcrowded anchorage and another boat decided to anchor right on top of us despite all our efforts explaining the couple that they were in risk of getting their very small boat crunched by our 23 tons once their boat aligned with all the other boats in the anchorage so despite having been safely anchored in that spot for a couple of days we decided was not worth the risk and lifted anchor and moved carefully out of the very crowded anchorage in complete darkness and with a thunderstorm starting to find a place somewhere else.

While trying to re-anchor in a nearby empty beach we ended up getting a plastic bag caught in the engine propeller leaving us just with the bow thruster to manoeuvre, in the end the bow thruster also caught a plastic bag and the mechanical fuse did its job protecting the motor but leaving us with another costly repair, luckily we did have a spare mechanical fuse on board and have seen how to replace it previously we knew exactly what to do.

A few more months passed by and our journey had already brought us across a good portion of the western Mediterranean and now we were arriving in what would be our last stop before heading to Tunisia, our winter destination.

Palermo in Sicily would be the last stop for the season an the third time we would go in to a marina since crossing the Ibiza Channel towards the Balearics, having a bow thruster is a must because we always end up in a berth for a smaller 45ft boat, and it is not easy to squeeze us in especially with a stern as wide as ours.

Long story short the bow thruster worked only on the first burst and then it just didn’t have the power to thrust again. Ana had already noticed that the bow thruster seemed to be working intermittently and she now turned the charger on well in advance of us starting the docking manoeuvres but this time it just didn’t work.

When arriving Hammamet we had our final confirmation, the bow thruster batteries need a much longer time to recover from use than before, after all, they are five years old.

This ongoing issue of the bow thruster intermittently not working due to the fuse breaking because of rubbish in the water or because the batteries are simply old can be a real pain when trying to manoeuvre a 50ft sailing vessel into a berth especially one as wide as ours at the stern.

So to understand, our bow thruster is a retractable thruster and it must drop down before it will thrust. After a few tests and playing with the system checking the charge etc, we think we have identified the problem as dead or dying batteries.

If we charge the batteries up we get the bow thruster mechanism to drop and thrust for about 30 seconds before the system considers that there’s not enough power and goes into fail and retract mode. We have found that there’s maybe enough power for the thruster to drop and retract but not enough to actually thrust efficiently beyond the first burst.

The AGM batteries are now right on five years old and we believe at the end of their life, again we don’t know the story of how were they cared for before we bought The Dream, so next expense is to replace the two batteries that form the 24 volt bow thruster power bank, one thought is, do we need to replace the specific charger for the bank with a new more reliable one, more research to be done here before we spend more money.



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