LOOS Tension Gauge/Model A-91

Manufacturer part #: Model A - 91

Part No.	Description
Model A-91	Cable Sizes 3/32", 1/8", 5/32"
Model B - 90	Cable Sizes 3/16", 7/32", 1/4", 9/32"
Metric - 91	Cable Sizes 2.5mm, 3mm, 4mm
Metric - 90	Cable Sizes 5mm, 6mm, 7mm

The Loos economy tension gauge takes the guesswork out of cable tension adjustment. It's especially designed for accurate, repeatable tuning of a sailboat's standing rigging. Manufactured of rugged anodized aluminum, the gauge is corrosion-resistant and will provide years of service. To measure tension, simply hook the Loos gauge on the cable as illustrated (see picture above). Pull the lanyard (Blue arrow) until the pointer is positioned at the black calibration mark (red arrow), read the scale at the exact point where the middle of the cable touches the scale (white arrow). For best accuracy, the gauge should be held so that the scale barely touches the cable, thus eliminating friction.
A word of caution, however: excessive pull on the lanyard, which pulls the pointer beyond the calibration mark, may permanently bend the spring and damage the gauge.

To convert the scale reading to actual tension in pounds for each wire diameter, see the conversion table on the gauge.
How Much Tension
Table 1 recommends an initial tension setting, but there is no simple solution since the optimum rigging tension will be a function of the boat design, the rig (masthead or fractional, one or more spreaders, etc.), and even the cut of the sails. Many skippers use insufficient tension because of a fear of "breaking something." It should be noted that on America's Cup contenders, where electronic state of the art tension instrumentation is available, the standing rigging is set as tight as is structurally feasible.

Table 1
302/304 1x19 Stainless Steel Rigging Cable
Ø In.	Breaking Strength Pounds	Forestay* Pounds	Shrouds* Pounds
3/32	1200	180	120
1/8	2100	320	240
5/32	3300	500	350
3/16	4700	750	500
7/32	6300	1000	700
1/4	8200	1300	850
9/32	10300	1600	1050
5/16	12500	2000	1300
3/8	17500	2750	1850

* Suggested initial settings.

One Design Class Racing Sailboats
Most sail makers who produce sails for the one design classes provide each purchaser with specific set of readings on theLoos Model A or Model B tension gauges for use when setting up the standing rigging. This assures that the sails will have the correct shape when the rig is under load.

For the convenience of sailors who wish to upgrade from our Model A or B gauges to the professional model (PT-1, PT-2, or PT-3) gauges we include below a conversion chart so that the same recommended tension can be obtained with the PT-1, PT-2 or PT-3 gauges as with the Model A or B gauges.

Model A	Model Pt-1			Model B	Model Pt-2			Model Pt-3
	3/32	1/8	5/32	SCALE	3/16	7/32	1/4	9/32
5	6			10	11
10	9			15	13
15	12	14		18	15
20	16	16		20	16	18
25	20	19		22	18	20
28	23	21		24	19	22
30		22		26	21	24
35		27	25	28	23	25
38		30	28	30	25	27	25
40	33	30	32	27	29	27
42			33	34	29	31	39
44			36	36		33	31
45			38	38		36	33	6
46			39	39		37	34	7
47			40	40			36	9
				41			37	10
				42			39	11
				43			40	12
				44				14
				45				16
				46				18
				47				20
				49				25