boat owner

Rig tension gauges

PBO results and verdict

■ Thanks to David Aldridge of Aladdin’s Cave Rigging for providing the 5mm wire used in the test.

RESULTS: Shroud 5mm 1x19, 316 Stainless Steel, Breaking load 22kN*

Shroud tension Gauge readings in kg Rdg % break load Load kg

Kg N As % of

UTS*

Loos

Standard

Loos

Pro

Spinlock

Rig-Sense

SureCheck SureCheck

1 100 981 4.5 109 120 140 4 80

2 200 1,962 8.9 263 240 235 7.5 150

3 300 2,943 13.4 380 320 350 15 300

4 400 3,924 17.8 510 450 450 20 400

5 500 4,905 22.3 650 550 580 42 840

A

s we expected, the readings taken

from the gauges varied slightly

from the actual loads. There will be

a number of reasons for this.

Firstly, some readings require some

interpolation between two marks on the

scale. There is some skill in operating the

gauge: the effect of friction, which can lead

to a false reading, has to be reduced.

From the graph, the SureCheck fi nal

reading looks suspect, but this was

probably because the conversion graph

tended to a horizontal line at the upper

range which made for larger reading error.

The Loos Standard gauge was simple to

use, but could not be left on the shroud

when it was being tightened. The Loos

Professional gauge gave a more accurate

reading than the Standard gauge and

could remain on the shroud during

tension adjustment. The SureCheck

was straightforward to operate, but it

was more diffi cult to obtain results at

the top of its range.

The Spinlock Rig-Sense was the only

gauge that allowed the load to be read

directly and whose design eliminated the

effect of friction in the mechanism. For

ease of use it gets the best buy, but

until the model range is extended to

accommodate larger-diameter wire,

it has limited applications.

Spinlock Rig-Sense

PRICE: £125.00

Contact: http://www.spinlock.co.uk

The Spinlock Rig-Sense is a new rig-tuning
tool developed to give consistent and
repeatable measurement of loads on
different wire composition as well as fi bre.
It is manufactured from anodised aluminium
with glass-fi lled copolymer components and
a composite leaf spring. The wire grips are
stainless steel, which should reduce wear and
give constant readings over time. The leaf
spring is calibrated to output load readings
to a direct linear scale in kg. The Rig-Sense
allows one-handed operation, and comes
with a carry bag: an app can be downloaded
to smartphones or tablets to enable readings
to be recorded and shared for future reference.
This is easy to use and gives a direct
load reading: it can be left in position
while adjusting the shroud tension. The
design eliminates friction, which should
lead to consistent readings.
It is currently only available for 2 to
5mm wire.

The leaf spring is calibrated to output
load readings to a direct linear scale in kg

As we expected, the readings taken from the gauges varied slightly from the actual loads

The Spinlock Rig-Sense was the only gauge

that allowed the load to be read directly

* Breaking load and Ultimate Tensile Strength (UTS) are taken to be equivalent