The Harken Rigtune Pro is a innovative take on the traditional Loos Gauge from the good folks at Harken. Introduced in the fall of '07 it's not brand new but now's a great time to pick one up if you're in the market since they're on sale for $280 until the 30th so get 'em while they're hot.
What makes this one so special and why does it cost so much? Well those are both fair questions. The Rigtune has a digital readout in kgs which allows it to be much more accurate than the standard Loos gauges which give you a number that you then compare to a scale. If you've used them you know that the scale is usually in 3-5 number increments so if you're in between you just have to give it your best guess.
With the Rigtune you get a specific result each time. The readout is in kilograms so if your tuning numbers are in pounds you'll need to do some converting which isn't too hard but it is an extra step. The unit has only two button - on and off so just because it's digital does mean it's hard to use.
Operating the Rigtune Pro is very easy. You turn it on and then hold down the on button for 3 seconds (that's according to the instructions, it seemed to require more like 4-5 for me) to zero it out. You place it on the wire and then just push down the arm shown on the left in the top picture until it's tight. That's all there is to it.
The Rigtune is good for 2.5 to 5mm wire (3/32" - 3/16"). I tested it on both 3/32" and 3/16" and found that it worked fine. On the 3/32" I tested it lined pretty much right up with the Loos gauge I tested. On the 3/16 wire the Rigtune actually showed a much higher tension than the Loos did - I expect this might demonstrate some of the inherent problems with the Loos in that it's very difficult for the springs to be accurate over the full range of the gauge.
I spoke with our Harken distributor who has tested the Rigtune thouroughly with a load cell. He says they found it to be accurate within .02% - which is pretty good and more than likely less than the tolerance of the load cell. He said if they load up several different sizes of wire to the same tension the Rigtune will read exactly the same for each one. You'd be hard pressed to get the same results from the Loos I think.
One thing I did notice with the Rigtune is that if I left it on the rig for a couple minutes the number went down over time - on the J22's 3/16" shroud it dropped about 10-11 kgs over 2 minutes. When I zeroed it out again it started back at the original number again. I've got a call into Harken about that to find out whether it's normal or if there was a problem with my unit.
Overall the Rigtune is a really neat piece of technology. Rig tensions have never been measured with this kind of accuracy before. It will handle pretty much any dinghy all the way up to J/22s, J/24s and Etchells. If you're looking to get detailed and definitely repeatable rig tension numbers this is definitely the tool for you. If you haven't tuned your rig more than twice this year it's not gonna be worth the investment but if you check & adjust it often I think it will give you numbers that are more accurate than the Loos and it will continue to be accurate for a longer period of time.
Harken have a video on their website put together by one of their guys in the UK with a really good explanation of how to use the Rigtune.