Rig Tension.

[storm petrel]

Hi All,

Does anyone have the good oil on Tophat rig tension. My leeward lower starts to get loose when the heel angle starts to dip the gunwale. Is this about right or should I put another turn on the lowers?

I also find that my backstay tension is not really adjustable because when I loosen it to fill the main a bit more the furler tube starts to move about disturbingly even when it is rolled up. I have, to date, opted for 'set and forget'. What does everyone else do? Is this a problem for those boats with furlers? Is backstay tension not worth changing on a Tophat?

Any advice would be welcome.

Cheers,
Mark

[auriga]

I was just about to ask a similar question, sorry to hijack yours!

In addition to Marks query;

I had the rig on my Mk3 replaced by a professional rigger late last year, it may be my imagination but it feels like the shrouds are getting looser than they were... is it normal for the wires to stretch a little?

I may be imagining this but it certainly seems looser than it was, is this something to be concerned about or just give them a tighten?

cheers
dan

[Tales]

There have been a few threads on this subject but not sure where they are now.
Most experienced TH owners say leave the back stay alone.
The logic here seems to be that is a straight mast and there will be very little change tight or freed off.
Regarding tension, there are a number of guides to rig tension on the web but most rely on having a tensiometer.
In the end I bought one and it has made my life much simpler!
Whitworth have the Loos one which is what I bought - make sure you get the right size for your particular rigging.
New rigging does stretch and will need retensioning.
Cheers,
Tom

[Phillip]

Evening Tom, Dan, Mark and All,

This quesion has been raised before but the answer to what the tenions should be was never answered.

Tom do you have the correct figures?

I had mine adjusted by an old Top Hatter (by eye and feel) and this stopped the mast vibrations
that some of us were getting, but I am sure I can sail better than my present situation if the tension was correct.

Phillip
SEAKA

[Dolphin]

G'Day all,
The only thing I was told was that the shrouds should never be slack as that will fatigue and cause cracking of the wire.

I have given up and never adjust the backstay tension. Like wise Mark, if I do loosen it off the forestay sags off and flogs around.
Paul Minter re rigged Felicite and overtightened the stays. He recommended to sail it for 1 month and then retension it after the stays had settled in.

Hope it helps.

Greg
Felicite.

[Tales]

Fellow Top Hatters,
The following from Loos and Co

The Loos&Co range of rig tension gauges provides a convenient and accurate means of setting
shroud and stay tension on a racing or cruising sail boat. The range of gauges comprises the
Standard range and the Pro-range. The Pro-range offers repeatable accuracy of 3% whilst the
more modestly priced Standard gauge offers an accuracy of 5%. The Pro range gauges can be left
on the wire while the tension is adjusted, the Standard range gauges must be removed while
tension is adjusted. Loos&Co produces tension gauges for wire up to the very large diameters
used on super yachts, but here we will confine ourselves to the following gauges and the wire
sizes they suit:
Type A; Standard; Reference 91M: Wire diameters 2.5mm, 3.0mm and 4.0mm
Type B; Standard; Reference 90M: Wire diameters 5.0mm, 6.0mm and 7.0mm
Pro PT1M: Wire diameters 2.5mm, 3.0mm and 4.0mm
Pro PT2M: Wire diameters 5.0mm, 6.0mm and 7.0mm
Standard Type B Gauge Pro Series, PT2M Gauge
Operation of the gauge:
Hook the gauge onto the stay or shroud, pull the lanyard until the pointer is positioned at the
black calibration mark and read the value at the point where the centre of the wire meets the
scale.
Use the scale mark as a reference, or convert the scale reading into actual tension in kilograms by
reference to the conversion table on the gauge.
How much tension? :
The following table gives recommended initial tension settings for 1 x 19 wire rope. It should be
noted that optimal rig tension will be a function of the boat design, the rig and the cut of the sails.
Wire diameter Breaking strain Forestay tension Shroud tension
2.5mm 550 kg 80 kg 55 kg
3.0mm 950 kg 145 kg 110 kg
4.0mm 1500 kg 230 kg 160 kg
5.0mm 2000kg 340 kg 230 kg
5.5mm 2800 kg 450 kg 320 kg
6.0mm 3700 kg 590 kg 390 kg
7.0mm 4500 kg 680 kg 450 kg
Leading sail-makers provide rig tension information for certain boats and sails and these should
be followed where applicable. If no specific information is available use the above table and the
following comments to establish a basis for tuning your rig.
Forestay tension – masthead rig: It is almost always advantageous to set the forestay tension as
high as possible within the limits of structural strength. Generally, it is possible to use 15% of the
breaking strain of the wire as the forestay tension. The backstay should be adjusted to maintain a
straight mast with the desired forestay tension. The backstay tension will be less than the forestay
tension because the backstay makes a greater angle to the mast than does the forestay.
Note that rollerfurling jib tension can only be set by adjusting backstay tension.
Forestay tension – fractional rig: Because the forestay tension cannot be directly balanced by the
backstay tension some mast bend is accepted and the sails are cut to accommodate it. Forestay
tension of at least 15% of the wire strength is desirable but, if this should result in excessive mast
bend, it may be necessary to back off the tension.
Upper and lower shroud tension – masthead rig: The initial rig tension should be high enough
that the leeward shrouds do not go slack when sailing close-hauled in a brisk breeze. The proper
tension for your boat can be found by a few test runs under sail and then the Tension Gauge can
be used to record and maintain this value.
For many boats a shroud tension of 10% to 12% of the wire strength is adequate. In some rigs it
may be advantageous to carry a bit more tension in the uppers than the lowers.
Upper and lower shroud tension – fractional rig: In most cases the same comments apply as for
masthead rigs. However, there is one exception. Where the upper and lower shrouds on a
fractional rig lead to chainplates located aft of the mast – swept back spreaders – most of the
forestay tension is balanced by the upper shrouds. A shroud tension as high as 20% of the wire
strength may be required to achieve the desired forestay tension. Never exceed 25% of the wire
breaking strength.
The Loos Tension Gauge is designed for use on 302 and 304 grade stainless steel 1 x 19 wire rope.
If used on other wire types the readings will be repeatable, but the actual tension values in
pounds or kilograms will differ from those given on the table on the gauge.

All the best,
Tom

[Phillip]

Thanks Tom,

Now I will have to locate a Loos gauge
Phillip
SEAKA