A glassy smooth Careel Bay beckoned me to do some speed trials. Cos so far there’s always been a bit of wind and it wasn’t clear just how much the wind was contributing to, or slowing her speed.
So I dropped the mooring and started taking notes as she wove out through the moorings.
1630 watts = 4.5 knots
4600 watts = 6.2 knots – full throttle
Strange… in earlier tests I was confident that she was topping out at about 6.5 knots so this is odd to see maximum speed a little less than I expected. Perhaps those readings were wind assisted. Anyway, back to it. I’m using the stop watch on my iPod Touch to time how long it takes to come to a full stop. And then I can do the same test late with the standard prop. Back to neutral and then to full power in reverse.
Clunk
and the watts drop off to around 700. What was that? Can’t see any obstruction to the prop. Try forward – also in forward the maximum load is about 700 watts.
Broken ends of pin sat at a nice angle to grab the shaft
I suspect the shear pin may have broken. Now I’m worried the prop might fall off, so I throttle back to about 100 watts and she’s going along at 1.5 knots. I haven’t gone far from the mooring, the day is still calm, so I’ll limp back ok at this speed.
Sure enough the ends of the pin have sheared off as designed and have laid against the shaft in such a way that they still grab a prop a little. 700 watts worth actually.
Speculating about the maximum speed being reduced, and remembering having hit some big jellyfish last weekend, its likely that the prop has been slipping just that little ever since the jelly fish encounter. One of them really got hit with the prop and the motor almost stalled, and it was probably then that the pin sheared.
Pin ends have rubbed a slight groove in the shaft
So its rather clever of me to have decided to do this test today in perfect calm, and discover the problem. Otherwise I may not have noticed until the chips were down and I really needed it. I now think the clunk I heard was the pin ends swapping around as the load reversed on the prop.
Its nice that the nut didn’t come undone with the free spinning of the prop on the shaft. And drop the prop into the sea.
Back in Sydney Harbour about two months ago I had a problem with a wobbly throttle control. I anchored right away in nearby Farm Cove and that afternoon Claude instructed me on making a temporary fix using Loctite to stop the bolt from loosening again.
Since then Claude has been to The Torqeedo factory and returned with a new throttle control of a new design that precludes this problem from raising its head again.
Torx bolts hold the plate onto underside of controller
The mounting plate is held by torx head bolts which I can undo with the Leatherman tool. Crikey! A leatherman is a handy thing to have on a boat.
Removing the mounting plate reveals an intriguing connection between the throttle lever and the control box electronics. Well, actually no physical connection at all – its uses a magnetic field for this analogue to digital interface. This is a nice idea for a marine environment – its leaves no entry point for water.
Underside of control - no axis for lever to attach to - its done by magnets.
This job only took a few minutes (and even longer to take photos of and write about!) and I gain a spare throttle lever. Now thats fixed I have no excuse but go on with repairing the cockpit seat.
The chart is of Broken Bay, of which Careel Bay is a minor part, on the edge of Pittwater. I enjoyed plotting our course down to Sydney, and then Port Hacking – the chart plotter was out of action due to losing the GPS antenna. Which is a pity cos it cost $475 for a new one. Even though I sometimes plot our position on a paper chart, it comes from the GPS coordinates. So it was fun to do it from compass bearings and other coastal navigation techniques.
Careel Bay is on the doorstep of the rugged Ku-ring-gai national park and I’ve just spent the last week or so there with Deb exploring the interesting bays and anchorages.
There's a climb up to this waterfall at Castle Lagoon
Searching for waterfalls was one of our favourite adventures ashore. The one in Refuge Bay is well known – its right on the beach and kind of obvious. And many of the other inlets have waterfalls but they’re not immediately obvious. But we were lucky because it was often raining that gentle misty rain and it meant they were all flowing nicely.
Ross and Sandra Cook visited as well the first weekend and they showed us around – they knew this area well from sailing their boats here.
We had Castle Lagoon to ourselves...
The whole area is the flooded lower reaches of the Hawkesbury River and the creeks that flowed into it. I guess it got flooded when the last ice age ended. So now we have steep sandstone gorges with deep water right up the banks. Here’s a link to a cool landsat image of this area.
The National Parks provide moorings in most of the bays and inlets for use by visitors – an overnight limit means musical chairs for moorings on weekends. But weekdays we could choose pretty much anywhere. But Jerusalem Bay’s three moorings were already taken when we arrived in the afternoon. But then America Bay is a good fallback – it has dozens of moorings.
me: Did you say 79 dollars?
cashier: Oh yes – ours is an expensive shop. Our prices are really high you know – this is the only shop around here.
There’s a kind of wild honesty in this exchange at the kiosk at Cottage Point. She didn’t even make the slightest no attempt to make excuses about their high prices.
Waterfall at America Bay - also a climb up to here.
We expected the groceries to cost about 30 bucks. So be warned. Carry plenty of spare change if you shop at Cottage Point. Its an otherwise a delightful settlement on Cowan Creek. Surrounded by wild bushland and yet not that far from suburbia – perhaps 20 minutes drive. Or 20 minutes by dinghy from Castle lagoon.
And how about the shark… on the way in to Cottage Point a shark jumped full length and did a 360 spin while out of the water. A case of Dolphin envy no doubt. It was about 4 ft long and grey with white trim. I’ve never seen a shark jump out of the water before.
And I took a look at the Torqeedo humming gently at back of the dinghy and decided that it could it do with a little more throttle.
Shark bait
Sailing in these waters can be quite a challenge, especially with the wind coming from where we are heading. Because of the steep slopes beside these narrow inlets the wind swirls around and never seems to stay the same strength and direction for more than a minute or two. And most of the time when we sailed it was on the jib alone. It could be slow or difficult to tack in these conditions so I found it useful to have the motor running at a very low throttle – even set at a measley 100 watts was enough to help her around in the tacks, and be barely using any power. And as soon as she picked up just a little speed from the wind, the power used by the motor would drop away to zero. This was nice compromise and made for quiet comfortable sailing.
On the last day the wind was very light and I expected it to stay light until the afternoon. We were looking forward to a gentle sail back to Careel Bay. I’d put the full main up to get the most of the light airs when soon after leaving America Bay the wind picked up a little. In the gusts we were doing 12 to 15 knots and because of the flat water she doing it really easily. I noticed about then that the motor was acting like a generator and putting plenty of power back into the batteries. The Torqeedo Cruise 4 is not promoted as having this capability so this came as a nice surprise.
Yoeman's Bay
It was while I was checking the amps – running at up to 18 amps charging the batteries – that I felt her accelerating madly. Deb was at the wheel and called my attention. We were copping a powerful gust of wind and in a matter of seconds we were doing 25 knots and she was heeled more than I was used to. I was standing ready to release main sheet traveller when we noticed the dinghy and two bean bags being dragged off the port trampoline by the wind. Our attention was needed elsewhere and we could only watch as one by one they went overboard. The melee kept up for about a minute before the gust died away and we were back sailing at a sedate 15 knots again.
Pity we had to drop the main and go back in search of our flotsam…
Thats the fastest she’s been since I’ve owned her. It sure is a wild ride. Here’s a movie by Sandra from a few days earlier with just the jib – she’s doing about 10 knots CS-Pittwater-Mar010 – iPhone
Going back to pick up things meant we used the motor more than I intended so we had to run the genset for a while to top up the batteries while going back to Careel bay. So it was comforting to have this backup power supply.
I’m now back on the mooring and tidying up ready for the next adventure. As with most outings something seems to get broken… this time it was the antenna for the GPS that was taken away off the aft deck. Owning a boat and sticking to a budget just don’t mix.
