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Monday, 6 June 2016

A repair bill dodged

Traversay III's propeller is of a type that feathers when it is not pushing the boat along. A clever internal gearing arrangement aligns the blades with the water flow when the engine is not powering the shaft, thus reducing drag considerably and disallowing the noisy wind-milling [water-milling?] of the shaft.

Feathering the propeller is accomplished by briefly shifting the gearshift into reverse after shutting down the engine and then shifting back to neutral.

After a period of motoring a few weeks back in the trip, we went through this procedure and found that, after selecting reverse, we couldn't shift back to neutral. The gearbox was jammed in reverse! This didn't bode well for future use of the engine but, since we travel in a SAILboat, wasn't an immediate cause for panic. Brief thoughts of using the dinghy to tow Traversay to the Australian customs dock flashed through our heads .. but first, "can we get it out of reverse?"

While we are not supposed to start the engine in gear, doing so established that we had complete control of the engine with forward and reverse gear available. On shutting down again, the choice seemed to be between an interminably noisy spinning shaft OR a gearbox jammed in reverse. We began contemplating the gearbox repairs necessary on our arrival and the lifting out of the water required to effect them but decided such troublesome thoughts were best procrastinated.

Weeks passed when, while sailing at a slow crawl just north of the equator, I filled one of my night watches with further experimentation. I found that I could get the gearbox out of reverse by rotating the shaft by hand in the reverse direction but then it immediately started spinning forward, presumably from water flowing past the blades like in a turbine. This would not happen if the prop were feathered. A new idea emerged: what if the problem is not the gearbox at all but that the propeller itself is jammed - will not feather - and thus "wants" to spin in the passing wake.

It is true that propellers are not cheap to repair or replace either but there was at least the possibility it was simply jammed with a stray piece of rope.

Now fast forward to a few days ago during a brief period of motoring when the trade winds died for a day or so. What an excellent chance to take a look at the propeller!

We stopped the motor, trailed a long safety line overboard and dropped the mainsail to the deck. I put on a mask and snorkel while waiting for Traversay's considerable momentum to dissipate and then climbed down to the swim platform on the stern. After further waiting, Mary Anne tossed some tissue paper in the water to gauge that we were truly stopped having no wish for Traversay to be floating in one place while I was floating in another some distance away.

Even before I started to climb down the swim ladder, huge waves were washing over my legs as I stood on the swim platform. Then, what an amazing sight as I got to the bottom of the ladder and peered down! The ocean was outrageously warm and totally clear. Not a speck of silt or any form of detritus intervened between my faceplate and the keel suspended seemingly weightlessly in a blue globe that went down and down forever.

I dove under the boat and instantly saw our problem: a piece of fishing net was tangled in the prop. Holding onto the prop-shaft, bucking up and down from the wave motion, I tried to disentangle the net. Unfortunately, the imperative of needing to breathe interfered with completing the now suddenly time-consuming task.

Back at the surface Mary Anne suggested, and then immediately found, a dive knife and sheath for me to strap on. Even with the serrated edge of the knife, it took two more dives to complete the job of removing the net.

Since then, there has been a bit of motoring and a lot of sailing. Both engine gearbox [transmission] and feathering propeller are now behaving exactly as they should.

* * *

As I mentioned in a previous blog, our planned route is always subject to change. As in previous voyages, the (southern) winter weather again looks more threatening (to me, anyway) south of Fiji than to its north. We have made a bit of a turn and are now headed north of Samoa and Fiji. A rumor has been floating around in our boat that this turn was made solely because we could not keep the ice cube trays full of water on the previous heading. There is no truth to this whatsoever!

* * *

In other news, the sea temperature has finally dropped a degree to 30C. The freezer has dropped a degree as well to -11C. The cabin is down to 32C. It feels MUCH cooler!!


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At 6/5/2016 21:36 (utc) our position was 12°31.82'S 165°55.03'W

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