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Old 31-07-2011, 15:28   #31
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

Besides all the great suggestions above, here are a few others.
- - Measure off a nautical mile between landmarks on the shore. It should take 10 minutes at 6 knots to cover that distance. And of course do it in both directions and average.
- - If you propeller is behind your keel or in an aperture (cut-out part of the rudder) check to see if the "diameter" of the propeller is large enough to get a good "bite" of water passing around the keel. A larger diameter propeller and lower pitch can make a big difference especially if the hull/keel is blocking clean water flow from the propeller.
- - If you are only going to use the boat as a cruising vessel then a fixed propeller is more efficient. But for high-speed sailing/racing the folding or feathering propeller is preferred.
- - You can also get in the marine supply stores (or internet) a "knot-stick" device. I think Davis Instruments sells them. They are plastic tubes with a spring inside and graduations on the outside of the tubes. Attached is a long string with an assortment of metal "washers" that you attach to the end of the string. You drag the string/washer behind the boat and the little indicator in the plastic tube will align with your speed through the water. This removes any problems with currents affecting GPS sog readings.
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Old 01-08-2011, 16:47   #32
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

Just for closure on this thread... OK, so I received a reply from Maretron....

"The issue you have reported may be as a result of an older version of firmware loaded to your device."

No ****? Apart from a "WTF?!? How did something THIS catastrophically obvious get past QA and released to the market in the first place?!?!?" reaction, I updated the firmware and did a few runs again and voila, normal speed.

I had original thought that Maretron was the Ferrari of instrumentation etc - but it appears that they're using the old Datsun QA department...

Older version of firmware indeed. Yeah, shows half the fscking speed..

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Old 01-08-2011, 17:25   #33
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

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Originally Posted by akio.kanemoto View Post
Yes, the positions reported agree. (I didnt look at exact LAT/LON numbers, but the handheld has a map on it and it shows my location correctly, as does Maxsea TZ, which received the Maretron GPS200 output.

As for where we are - we'll be moving to where you were very shortly. Pittwater.
G'Day Akio,

First, your later post revealed the firmware issue. I share your disgust with any company that allows such a defect to reach the customer.

So, where in Pittwater? Some bloody day we will be back aboard, and will very likely spend some more time there prior to heading for Tassie around Christmas or early January. Anyhow, it would be good to have an eyeball then. And good luck with lighting a fire under your rigger. Mastless yachts look funny...

Cheers,

Jim
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Old 01-08-2011, 17:34   #34
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

akio-
WRT wetsuit hoods, years ago I saw Jaque Costeau (not in the flesh) diving with a red wool watch cap and I said to myself, wtf, why does he wear a watch cap instead of a hood? It turns out that a heavy wool watch cap HELPS in the water, and when you come out it works very nicely, especially if there's any wind chill to be stopped. So if you've got no hood...grab a couple of watch caps. Which are also good padding in zero vis when you headbump the hull.

So, now we have to suspect the firmware load in instruments. Sheesh! Call DHS and report it as intentional cyberwarefare, tell 'em those buggers are trying to sink ships. Are you the registered owner of those instruments? They couldn't afford to send out some post cards?

Let the hull get good and foul, then we'll keelhaul 'em.
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Old 02-08-2011, 15:11   #35
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

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G'Day Akio,

First, your later post revealed the firmware issue. I share your disgust with any company that allows such a defect to reach the customer.

So, where in Pittwater? Some bloody day we will be back aboard, and will very likely spend some more time there prior to heading for Tassie around Christmas or early January. Anyhow, it would be good to have an eyeball then. And good luck with lighting a fire under your rigger. Mastless yachts look funny...

Cheers,

Jim
Yes, boat looks very funny indeed, sans lifelines and a few other things as well... I'm sure you've noticed after living in Australia for so long that it's a beautiful place, but everything is hideously expensive yet customer service really sucks.. so on this note, I'm actually waiting on a whole list of stuff waiting to be delivered "any day now" (which could be another month!).

As for where in Pittwater/Broken Bay - actually I don't know. We don't have any liveaboard or cruising experience at the moment - (but damn I have a lot of new mechanical, welding and fibreglassing skills!) - so we were thinking of starting with somewhere in Pittwater so it's just appropriately inconvenient (to provide a gentle introduction to cruising), but not overly inconvenient. I imagine that during the first month - I will still need to buy or fabricate missing "stuff" - so want to be close to Sydney (where I've setup a workshop in my parents' garage... ahem), but not too close as my mooring is literally a few hundred metres from there. Hence Broken Bay.

Once we've spent a few weeks there, we'll be moving North in day hops (assuming that our ~8 ft draft allows us to enter the various ports! hopefully this wasn't a gross oversight..) but will be back for the NYE fireworks in Sydney and a few weeks after that will again head North to start our circumnavigation. Very exciting stuff.

Any ideas for anchorages in Pittwater/Broken Bay? Also, how do you handle pumpout/emptying your holding tank etc? Our holding tank is a bit on the small side..

Let me know when you're going to be back and we can meet up.
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Old 02-08-2011, 15:14   #36
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

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Originally Posted by hellosailor View Post
akio-
WRT wetsuit hoods, years ago I saw Jaque Costeau (not in the flesh) diving with a red wool watch cap and I said to myself, wtf, why does he wear a watch cap instead of a hood? It turns out that a heavy wool watch cap HELPS in the water, and when you come out it works very nicely, especially if there's any wind chill to be stopped. So if you've got no hood...grab a couple of watch caps. Which are also good padding in zero vis when you headbump the hull.

So, now we have to suspect the firmware load in instruments. Sheesh! Call DHS and report it as intentional cyberwarefare, tell 'em those buggers are trying to sink ships. Are you the registered owner of those instruments? They couldn't afford to send out some post cards?

Let the hull get good and foul, then we'll keelhaul 'em.
Wow! Actually I remember the red cap on various documentaries in the 80's! I didn't think anything about it then, but now that you've pointed it out - good point!

Btw I did get a reply from Maretron after I told them it was a safety issue - the reply was something along the lines of "we are happy that your problem has been solved. that was an isolated problem in the initial production batch, we have since introduced new processes to ensure this doesn't happen again"... err.. you mean like basic testing?
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Old 03-08-2011, 00:07   #37
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

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Racing boats often do not have real auxiliary engines, they only have 'docking' engines, intentionally underpowered to stay lightweight, and just used when they absolutely have to be used. So not making speed under power wouldn't surprise me.

But an engine that big, on a boat that size, and presumably light displacement because it is a racer, ought to have more umph than that. If the bottom is clean, and the prop is clean (a fouled prop can cut your speed to nothing) and you're sure about the actual speed through the water, not just speed over bottom, then I'd suspect the engine is tired out.

Maybe low compression, try a cylinder leakdown test, I think you can buy a kit for under $50 if you don't want to bring in a mechanic. Could be the injectors, could be the whole usual raft of diesel problems but if the engine is simply OLD and tired...that would explain a lot. If you can get a referral to a competent mechanic (I know, ask at the local unicorn ranch) they should be able to spot something within an hour and not need to rack up a huge bill on diagnosis.
Unicorn ranch? That's really funny. Thanks for the laugh, I needed one. Rough refit day at the boatyard here and the laugh is appreciated.
A refit is a series of disappointing surprises.
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Old 07-08-2011, 07:55   #38
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

Here is the deal...Kiwi props suck as motoring props. Forward and reverse. The blade design makes them useless to motor.
I own 2 of them. I also own 2 fixed props. I switch them out as circumstances warrant...Kiwi props for passage, fixed props when I'm going to hang around a smaller area for a while. I can snorkel and do this (catamaran so the props are only about 1 foot down) quite easily.

In a 15 knot headwind I am lucky to approach 3 knots using Kiwi props. With fixed props I can motor into the same headwind at 6 knots.

The reverse thing is also an issue. This is EXTREME load on a diesel and very bad for the engine. Nothing can fix that aspect of this design.

Max props or Auto props are a better way to go.
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Old 13-08-2011, 09:29   #39
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

Wow 7.4 Kts! When I see water passing at that rate it make me wonder how quickly I will disappear if I was to fall over board.
Btw 7.4 Kts is 3.8 meter/sec, close enough to 3.5 that you mention previously. Normally a choice of units is available to select. May be the previous software had m/s as factory default and the new upgrade Kts. Not really that dramatic. Why m/s? That will be how quickly I would disappear if I was to fall over board, 3.8 meter /second.
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Old 13-08-2011, 09:40   #40
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

Curious. At 7.4 knots where did the bow wave end up? You said it was approx 3/4's back before.
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Old 13-08-2011, 09:52   #41
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

I'm surprised no one has suggested the transmission! Could it be slipping?
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Old 13-08-2011, 09:57   #42
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

Denise, he determined that it was a bad gps and that the boat was actually doing hull speed.
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Old 13-08-2011, 10:13   #43
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

Oops! "Never mind" (crawls back under rock)
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Old 13-08-2011, 10:35   #44
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Re: Six Year Refit . . . Is 3.5 Knots Under Power Too Slow ?

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Denise, he determined that it was a bad gps and that the boat was actually doing hull speed.
A Knot Stick is a much less costly and more reliable means of determining ones speed through the water and one needn't worry about batteries. Dolphins perhaps, but not batteries....
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Old 13-08-2011, 11:23   #45
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Whatever happened to a measured distance between two stanchions, a Timex watch,and some pieces of toilet paper?
That got me across the Pacific....as a check and backup.
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