I could use some help with rigging tension for our 1980 E38

our38

our38

Member II
I recently had to replace my backstay chainplate, as the original had a fracture at the top screw. Now it's time to tighten everything up and I could use a little guidance for tensioning all the rigging, as best as possible anyway.

I've done some basic tightening according to this P3 tool, but I'm sailing to San Francisco and thought this might be a good time work this stuff out. I'll have a lot of time on the water.

Any information will be much appreciated. I'm hoping I'll have internet access while I'm out.

John
 
footrope

footrope

Contributing Partner
Blogs Author
I have the data you need but I need to confirm the wire diameters and pointer values and add them to the table. I do know that for the forestay-backstay I have 5/16" wire and it is tensioned to 1500 lb (26 pointer) using a Loos gauge. Look for an update later today or Friday.

The setup below was done by a professional rigger, as an initial setup with new wires prior to going sailing. Mast was in column - no bend/rake.

E38 Standing Rig Tension Values, Loos PT-3, except on L/R Intermediate shrouds

Backstay, 5/16, 12%, 1500 Lbs, Loos 26
Forestay matches backstay

LH Cap Shroud, 9/32, 21%, 1540 Lbs, Loos 22
LH Intermediate Shroud, 3/16, 11.50%, 575 Lbs, Loos value unk,
RH Cap Shroud, 9/32,22%, 1540 Lbs, Loos 22
RH Intermediate Shroud, 3/16, 11.50%, 575 Lbs, Loos value unk

Lowers
LH Fwd, 1/4, 11%, 900, Loos 10
LH Aft, 1/4, 7%, 550, Loos 5.5
RH Fwd, 1/4, 11%, 900, Loos 10
RH Aft, 1/4, 7%, 550, Loos 5.5
 
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bgary

bgary

Advanced Beginner
Blogs Author
I'm (personally) not a fan of tuning by gauge-numbers. Nothing wrong with using a gauge, I'm just not (personally) convinced the gauge produces accurate data with the wire sizes we use.

So, color me "old school".... the process I use is
-- center the mast at the partners and put blocks on either side
-- raise a 100-foot tape on the main halyard, make sure it is not obstructed, measure to a known point on each side (I use the top of the pin for the upper shroud)
-- adjust the uppers until both sides measure the same - now the masthead is centered between the chainplates
-- snug up the uppers equally until you can only deflect them an inch or so when you pull on them
-- sight up the sail-track and see if there is any side-to-side bend between lower spreaders and masthead
-- adjust the intermediates until the mast is straight between lower spreaders and masthead
-- sight up the sail-track and see if there is any side-to-side bend between deck and upper spreaders
-- adjust the lowers until the mast is straight between deck and lower spreaders
-- snug up everything evenly until you can only deflect the shrouds an inch or so when you pull on them (*)
-- double-check measurements and sight up the mast track to make sure all is still centered and straight
-- (iterate as necessary)

-- adjust headstay and backstay until you have the amount of "rake" you want
-- (a good starting point is to have 4-6" between the gooseneck and a plumb-line hanging from the main halyard)
-- snug headstay and backstay equally until both are "taut" (subjective term, but should be less than an inch of deflection when you pull on them)

Now, go sailing. Ideally in 8-10 knots
-- raise the main, sail close-hauled on one tack, sight up the mast track, see if there is any side-to-side bend
-- if there is, tack, adjust the new-leeward shrouds to address the bend
-- sight up the mast track, see if there is any side-to-side bend on the new tack
-- if there is, tack, adjust the new-leeward shrouds to address
-- (iterate as necessary)

-- raise the headsail, sheet in, sight up the mast track to see if there is any side-to-side bend
-- if so, address as above
-- go to the bow and sight up the headstay to see how much "sag" there is in the headstay (**)
-- if more than 8-10" or so, tighten the backstay a few turns
-- (iterate as necessary)

(*) the E38-200 manual (available in the download section) has a full section on tuning the mast (section 6.2). It indicates that the forward lowers should be "slightly tighter" than the aft lowers.
(**) your headsails will have been designed with a certain amount of sag built into the luff-curve calculations. Might be worth a call to the sailmaker to see how much sag they designed for.

Unless you're running a high-end racing program on a boat with load-cells, static numbers at the dock don't really mean much. What really matters is: does the mast stay in column side-to-side when sailing, and do you have the amount of mast rake, mast bend and headstay to suit your sails, and to produce the "feel" you want (eg, weather helm) while sailing...

$.02
Bruce
 
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footrope

footrope

Contributing Partner
Blogs Author
footrope said:
I have the data you need but I need to confirm the wire diameters and pointer values and add them to the table. I do know that for the forestay-backstay I have 5/16" wire and it is tensioned to 1500 lb (26 pointer) using a Loos gauge. Look for an update later today or Friday.

The setup below was done by a professional rigger, as an initial setup with new wires prior to going sailing. Mast was in column - no bend/rake.

E38 Standing Rig Tension Values, Loos PT-3, except on L/R Intermediate shrouds

Backstay, 5/16, 12%, 1500 Lbs, Loos 26
Forestay matches backstay

LH Cap Shroud, 9/32, 21%, 1540 Lbs, Loos 22
LH Intermediate Shroud, 3/16, 11.50%, 575 Lbs, Loos value unk,
RH Cap Shroud, 9/32,22%, 1540 Lbs, Loos 22
RH Intermediate Shroud, 3/16, 11.50%, 575 Lbs, Loos value unk

Lowers
LH Fwd, 1/4, 11%, 900, Loos 10
LH Aft, 1/4, 7%, 550, Loos 5.5
RH Fwd, 1/4, 11%, 900, Loos 10
RH Aft, 1/4, 7%, 550, Loos 5.5
Click to expand...

Edited my original post. These settings were the initial values prior to going sailing. The procedure used was similar to Gary's procedure. I do not have a gauge for the 3/16 wire at this time, thus the mystery for the intermediates. Loos gauges have so much hysteresis that the values are really just advisory.
 
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