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Shroud tensions

Apr 16, 2020
4
Catalina Capri 22 Lake Travis
Hello folks,

I have recently bought a 98 capri 22 fin keel, standard height rig, race package boat that came with Gus mainsail and cdi furler (135 headsail on it)

I am ready to tune the rigging but have been getting conflicting advice on shroud tensions from local catalina owners, none are c-22 owners. Can you please share your experience and advise?

Opinion1: lowers should be 5-10% tighter than uppers because lowers hold the mast in column. Uppers should be less tight to allow the mast bend backwards above the lower shrouds in order to take advantage of fractional rig/split back-stay, while still holding the mast in column.

Opinion2: uppers should be tighter than lowers. Why: Uppers hold the mast centered left/right and carry the lateral load from the wind. Lowers limit the mast bend.

Your guidance is greatly appreciated.

Thanks,
John K
 
Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
The Capri 22 is a typical fractional rig, with one set of aft swept spreader. For all such rigs, the uppers are tighter than the lowers .

Added on editting: BTW, the cap shrouds s on a Catalina 22 masthead rig should be tighter than the lowers, too. It's physics and it applies to all masthead and fractional rigs.
 
Last edited:
Dec 21, 2016
20
2005 TRFK
Does anyone have actual Loos guage numbers that they use on their boats, for the upper and lower shrouds? Reading the Ulman and North tuning guides they both speak of 30 - 32 on the uppers and then tighten a couple of turns for heavier winds. 32 equates to only about 200 lbs of wire load on the 5/32 wire. My leeward upper shrouds would be very floppy at that setting even in 10 kts of wind.

The Selden tuning guide stresses the importance of the cap shrouds always being tight .. and infer guage reading of around 20% of breaking strength; which would be approx 45 on the guage.

Last Fall my leaward upper shrouds were set at about 42. That seemed nice and firm in most conditions. At 42 that is approx 12.7% of the breaking strength of the wire.

Anyone have actual data?
Dave
 
Jun 25, 2004
1,108
Corsair F24 Mk1 003 San Francisco Bay, CA
Anyone have actual data?
Dave
Here you go, data from two different lofts.


But be aware that you have to set the the amount of prebend you tune into the mast according to how your sailmaker built the sail. Not all Capri 22 sails have the same luff curve designed into them. I usually built my Capri mainsails to fit 1.5 inches of prebend in the mast.

Judy B
Retired sailmaker.
 
Dec 21, 2016
20
Thank you for the reply Judy B. I did mention in my original post that I have read those two Guides. And yes .. I am aware of the pre-bend requirement.

The Ullman Guide says: "On the Loos Model-A tension gauge, the lower shroud tension should be around 5." (for our 1/8" wire .. the guage doesn't even show a load reading that low).

The North Guide says 20 for the lowers at the same wind speed.
Wind SpeedUpper Shroud TensionLower Shroud TensionHead Stay
0-52818Max rake
6-93120Max rake

So .. what am I missing ?

I welcome all comments of course; but I posted here hoping that someone with an actual Capri 22 FKTR and a Model-A Loos guage could share their actual numbers.

cheers and hope everyone is staying safe ..
Dave
 
Apr 16, 2020
4
Catalina Capri 22 Lake Travis
UPDATE: Tested both options this weekend.

at the dock:
1- loosened all 4 shrouds (not completely flopping but barely hand-tight) , detached the boom, released split back stay
2- made sure the mast was side-to-side centered + made sure rake was correct
3-a- uppers tighter: uppers:31 / lowers:23 + used split back-stay to bend the mast above the spreaders eye-balling

Sailed:
about 8-11 knots winds leeward shrouds were too tight, loosened all 4 about 2 turns each. tension was right but upwind speed was eeehhh and could not point very well.

back at the dock:
3-b- lowers tighter: uppers:21/ lowers:20 + checked to make sure the mast bend above the spreaders was about the same

Sailed again:
same winds. leeward shrouds were nicely loose, no issues with head-sail sagging. Boat pointed better and faster

Result:
My boat speed was 2-4 knots faster when lower shrouds are tighter than the uppers. Owners Manual, rigging section also calls for tighter lowers. Having looser uppers allowed me to dump air in the upper part of the mainsail when winds were at about or more than 14knots. Less heel and more boat speed.

I will stick with this tune.