How to use RT Series Tension Gauges

We offer a series of gauges to measure the tension in rods from .172 to .375 inch in diameter over a range of approximately 5% to 25% of the breaking strength of the rod and provide an accuracy of + or – 5%.

Modell	Rod Diam
Model RT-10	Rod diam. .172, .198, .225, .250, .281
Model RT-10M	Rod diam .4mm, 5mm, 5.7mm, 6.3mm, 7.1mm
Model RT-11	Rod diam. .281, .330, .375
Model RT-11M	Rod diam., 7.1mm, 8.4mm, 9.5mm

MASSNAHMEN

Hold the gauge with the right hand and place the rod between the two nylon spools as shown in Figure 1. With the left hand pull the lanyard and extend the spring until the hook on the nylon slider can be hooked on the rod as shown in Figure 2.

Release the lanyard. Read the needle position on the scale. Refer to the calibration table to obtain correct tension in the rod. The gauge can be left on the wire for “hands free” adjustment of the rod.

To assure accurate readings make sure that the slider moves freely in the frame slot and does not bind. Lubricate the slider slot frequently with silicone lubricant.

WIE VIEL SPANNUNG?

Tabelle 1 empfiehlt eine Anfangsspannung, aber es gibt keine einfache Lösung, da die optimale Takelage-Spannung von der Bootskonstruktion, dem Rigg (Mastkopf oder fraktioniert, eine oder mehrere Salinge usw.) und sogar vom Schnitt der Segel abhängt. Viele Skipper verwenden eine unzureichende Spannung, weil sie Angst haben, "etwas kaputt zu machen". Es ist anzumerken, dass bei America's-Cup-Teilnehmern, bei denen elektronische Spannungsmessgeräte auf dem neuesten Stand der Technik vorhanden sind, das stehende Gut so straff eingestellt wird, wie es strukturell möglich ist.

Tabelle 1
Nitronic 50 Rod
	Breaking Strength		Forestay*		Shrouds*
Diam,. In.	Lbs.	Kgs.	Lbs.	Kgs.	Lbs.	Kgs.
.172	4700	2140	705	320	470	214
.198	6300	2860	950	430	630	290
.225	8200	3730	1230	560	820	380
.250	10300	4680	1550	700	1030	470
.281	12500	5680	1880	850	1250	570
.330	17500	7960	2630	1190	1750	800
.375	22500	10230	3380	1530	2250	1020

RENNSEGELBOOTE DER ONE-DESIGN-KLASSE

It is suggested that you contact your sail maker for the recommended initial settings for the rod rigging on your boat. For larger boats it may be prudent to check with the designer of the boat.

Wenn der Segelmacher keine spezifischen Anforderungen stellt, bieten die folgenden allgemeinen Bemerkungen eine Grundlage für ein rationelles Vorgehen bei der Abstimmung des Riggs.

VORSTAGSPANNUNG

Mastkopf-Rigg

On the masthead rig it’s almost always advantageous to set the forestay tension as high as possible within the limits of structural strength. Generally, it’s possible to use 15% of the breaking strength of the rod. Thus, a forestay tension of 1,550 lbs. is a reasonable and conservative place to start with a .250 diam. Nitronic rod.

Backstay tension would, of course, have to be adjusted to maintain a straight mast with the desired forestay tension. Since the backstay makes a greater angle to the mast, the backstay tension will be lower than the forestay tension.

ANMERKUNG ! DIE ROLLREFFANLAGE KANN NUR ÜBER DIE ACHTERSTAGSPANNUNG EINGESTELLT WERDEN.

Fractional Rig

In a fractional rig the forestay does not go all the way to the masthead and forestay tension cannot be directly balanced by tension in the backstay. Therefore, some mast bend is generally accepted and the mainsail is cut to fit the bend. A forestay tension of at least 15% of the rod strength is desirable. However, if this results in excessive mast bend it will be necessary to back off a bit. On some fractional rigs, diamond shrouds are used to reduce mast bend.

OBERE UND UNTERE ABDECKUNGSSPANNUNG

Mastkopf-Rigg

There is a simple criterion for shroud tension. The initial rigging tension should be high enough that the leeward shrouds do not go slack when sailing close-hauled in a reasonably brisk breeze. The proper value for your boat can be found by a few trial runs under sail. Once the correct tension is known, the gauge can be used to maintain the value.

For many boat designs a shroud tension of 10% to 12% of the breaking strength of the rod is adequate. Thus, for a .250 diam. Nitronic rod the upper and lower shrouds would be set to 1000 to 1200 LBS. tension. On some rigs it may be desirable to carry different tension in the uppers than lowers.

Fractional Rig

For most fractional rigs the correct shroud tension is the same as that for a masthead rig, i.e., a tension setting that will keep the leeward shrouds from going slack. However, there is one exception. On certain fractional rigs, the upper and lower shrouds lead to chain plates that are aft of the mast. The spreader is swept back. For such a rig most of the forestay tension is balanced by the upper shrouds. A shroud tension of approximately 20 % of the rod strength may be required to achieve the desired forestay tension. Never exceed 25% of the rod breaking strength. (Refer to the breaking strength chart Table 1.)

GAUGE MAY NOT READ “0” WHEN AT REST, AS THEY ARE CALIBRATED AT MIDRANGE OF TENSION.
HINWEIS ! WENN NACH LÄNGEREM GEBRAUCH FLACHE STELLEN AUF DEN NYLONSPULEN AUFTRETEN, DREHEN SIE DIE NYLONSPULEN UM 45°.

RT10 & RT-10M TENSION GAUGE – FRONT LABEL