On Saturday we took the Mk2 water speed sensor probe out for testing and calibration. I'm glad to say it all worked, and the new probe design has overcome the problem we had with the Mk1 probe of Bluetooth not working through water. So now we are all set to do some actual testing of junk rigged boats.

There are some videos that you can download from Dropbox here

 https://db.tt/3Fm2EbGlY7

I have sent an email to the previous volunteers for testing asking for possible dates and locations, but if there are any other owners in the UK interested in getting some independent performance data for their boat, please contact me. Although we are primarily interested in "interesting" junk variants, we also would like to have some traditional junk rigged boats for comparison, especially of those models which are often  rigged with JR, e.g. Newbridge boats, Westerlys, Sunbirds, etc.

Last week over a couple of days I tried out the JRA instruments on a friend's boat. Generally things went well, and the frame carrying the instruments did not break although it creaked and groaned a bit when the skipper tacked fast while we were creaming along at 7 knots, which generated maximum side force.

Unfortunately we hit a snag that none of us had foreseen. We were trying to calibrate the water speed sensor in Ipswich dock where there is nice flat water and no current, as it has a locked entrance. We could run at above 5 knots for long enough, but we discovered the fatal flaw, which is that to calibrate the sensor, we have to use a Bluetooth connection, (to a phone with GPS), which worked fine when we were stationary, but stopped working once we got above 1 or 2 knots and the probe kicked up a bit of a bow wave.

A bit of research on line led to the explanation - Bluetooth doesn't work through water. Apparently it uses a similar frequency to microwave ovens, so we were just trying to heat up the dock. I can see the system would work fine when the sensor is mounted in a boat, but it doesn't work in a probe.

So we have gone back to the supplier to ask if there is another way to calibrate the sensor, or to get the Bluetooth signal out of the probe - an aerial maybe? No reply yet, but I guess they have their thinking caps on, or maybe they're just on holiday.

If we can't make it work with the existing probe, I have a plan to change the probe so it sits on the water rather then in it, and has a spray rail like a fast motorboat to keep the bow wave low.

Either way, it's going to be a while before we can sort this out, but one way or another we will sort it out. If all else fails we can change to an older simpler sensor. I will post an update when we know how we are going to proceed.

Thanks for the update, Alan, it's looking promising.  If you need a 33' JR ketch with hinged battens for your portfolio I might be persuaded - once I get the RCD sorted.

Hello all.

 I happen to have a little 6.5m Monarch fin keel sailboat that I managed to dis mast last year. I am also in the process of trying to decide which would be the best rig (vs effort to achieve) on Stalemate which is a westerly konsort and would be pretty similar to Poppy. I would be interested in comparing cambered vs split junk rig. 

 The little boat could be on my mooring in Plymouth have two mast positions if needed to test different rigs. Would anybody be interested?

Regards

Mark

A thought, if it hasn't already occurred to other members.  

With regards to getting comparisons between different rigs on the same boat, what about the Coromandel/Corribee? 

Tammy Norrie owns an original Hasler/McLeod junk rig on a Coromandel boat.  He is contemplating putting a different rig on.  Maybe just the same but with camber, or a Split-rig or Weaverbird style.  Another Coromandel owner already has a Split-rig fitted, albeit maybe not totally optimised for the boat/mast position.  

The Corribee and Coromandel are supposed to have the same hull shape and dimensions and there are Corribee yachts out there with Junk Rigs fitted plus of course there are multitudes of Bermudan rigged Corribees which would make it possible to make a direct comparison with a Bermudan rig on the same boat.  

I'm sure a friendly Corribee sailor wouldn't mind helping out.  Maybe contact the Corribee owner's association? A polar diagram of the Corribee's sailing performance might be a small incentive for them to assist.   

Of course, there are different configurations underwater, like bilge or fin keels, and weights of individual hulls, (extra equipment, etc) but it might, over time, to be possible to  find hulls and owner's willing to help who all have the same configurations.  

Dave D.