36'-40' sailboat rigging-Survey

[delmarrey]

For sailboats between 36 & 40' what would you consider your rigging to be? And if you can, could you post a little statement on your boat size, displacement, stays & shroud sizes.

Mine has 3/8" (10 mm) forestay, 5/16" (8 mm) backstay, 5/16" (8 mm) Upper/Lower shrouds and 1/4" (6.35 MM) center shroud, on a 51.5' (15.7 M) mast w/ 15000# (6804 Kg) displacement.

[mainesail]

Hi, It's unclear what you're looking for. Generally speaking your wire sizes are about average for your boat size and displacement. What do you mean by center shroud-do you mean the babystay forward of the mast?

[SkiprJohn]

My wire sizes are just one down from yours and I consider my boat medium rigged. I do have an inner forestay and running backstays. 48ft off the deck mast and 22,000 lbs boat.
Is that what you were after?
Kind regards,
JohnL

[delmarrey]

Wire sizes! Yep! that's what I'm looking at. I'm curious how sailors feel about the rigging they have either for offshore or coastal experience.

As I walk through marinas I see some 36-40' class boats with small sized masts and booms and others with large sized masts and booms. And it makes me wonder why there should be such a difference. I suppose it would be the displacement of the vessel, keel design or type of rig (sloop vs. ketch, etc.)

I've looked through Yachtworld ads and it doesn't give wire sizes but does give mast height or bridge clearances.

My mast has two sets of spreaders. One set of shrouds goes to the masthead and the other two are to the spreaders. I seem to have a tall mast for my vessel compared to others (51.5' off the deck) and would like to know if the wire sizes are up to snuff compared to others.

My vessels rig seems to handle well out there and I've only seen the lee shrouds go slack once during a sudden gust but would like to have more confidence to take her out in a storm.

There seems to be two common failures in "monohulls" (excluding seamanship) in offshore situations, rudders and rigging.

Just doing some research!

[delmarrey]

That's a start.

[Sandero]

I have a unusual rig, it's single swept back deck stepped 7/8 fractional. So this means there are basically two std and two port stays and the forestay which support the stick. The backstay only functions to bend the mast for sail trim (flattening). The uppers and lowers are about 10mm - very thick compared to most boats of similar size. Boat is 36' /16K displ.

[Hud3]

Del,

I'd consider my Island Packet 380 on the beefy side of the middle range:

One set of spreaders.
Forestay & upper shrouds 3/8"
Forward and aft lowers, & dual backstays 5/16"
Staysail stay 5/16"
54' air draft
21,000 lb (9,526 kg) dry, about 12 tons cruising weight
Full keel, 9,000 lb lead ballast

[delmarrey]

defjef,

10 mm does seem to be fairly heavy but with only two shrouds I guess that would be reassuring. I've always liked the looks of a swept back rig!


Hud3,

One set of spreaders? It must be a fairly heavy mast! But IP's do have a good rep for construction. Beautiful boats!

Thanks!

[SkiprJohn]

Ok, now that I know what your after here's my rigging fore to aft. 3/8" forestay, 5/16" removeable staysail stay. Two upper (single spreader rig) and 4 lower shrouds are 9/32". Running backstays are 9/32" each and dual backstays are 9/32" each. Mast is 48' from step on cabin top. It is a cutter rig. Depending on how she is loaded the weight of the boat could be as high as 22,000 but more often she is less.
I think you have the right size rigging and would not (in my opinion) go up a size when you are rerigging.
I think Hud's boat is heavily rigged.
Hope this helps.
JohnL

[cal40john]

Cal 40, 15,500 disp., 11' beam, 700 sq. ft SA, 40' luff, 50' top of mast, single spreader 1/4" uppers, 9/32" lowers, 1/4 backstay, I'll have to check forestay. Haven't heard of many dropping their rigs in the last 40 years.

Righting moment is dependent on beam, displacement, center of gravity and other factors. Skenes Elements of Yacht Design has a formula to determine RM, but it includes metacentric height, which most people don't have. I have seen a way to estimate GM, by hanging a weight to heel the boat 1 degree then use a formula to extrapolate to 30 degrees. Skene's also has a graph which he says most boats will fall into. As an example the 30' LWL my boat has shows an average of 32,000, low 28,000, high of 40,000 foot lbs. (3 lines on graph). Tension on the wire also depends on chain plate beam and number of spreaders. For my chain plate beam, single spreader rig this ranges from 1/4" to 5/16" wire for the uppers from the above RMs. This was all done with his short method, with 2.5 safety factor.

Shrouds going slack doesn't have anything to do with the wire size needed, it has to do with how much you preloaded the rig.

John

[Stillraining]

FWIW:

I voted Medium

Irwin 41 Ketch
Disp 29000 (as sailed)
1097 squar feet
Singel Spreaders
Bridge clearance 54.5 to truck


Main mast:
3/8 Forestay and upper backstay until the split... then 5/16
Intermediats all 5/16
Soon to add 9/32 inter stay with spectra running backs for new storm staysail purchased.

Mizzen mast:
1/4 all
3/16 running backs

Worst conditions so far:
47 knots didnt faze her..looking forward to 50+ (inland)

[bob_77903]

I voted heavy..I will use Tartans specs, which are as follows.

1974 Tartan 41
Displacement 17,850
Ballast 9200
Sail area 725
Mast length 60'6" Bridge Clearance 58'
Single Spreaders
Single Upper shrouds 3/8"
Single lower shrouds 7/16"
Back Stay - Head Stay 3/8"
Baby Stay 1/4"

[delmarrey]

Thanks again to you SkiprJohn and Cal 40, Stillraining and Bob.

So far, it seems my rig is in the medium to heavy by comparison.

I have adjusted my shrouds according to the Loos graphs. I have a keel stepped mast and believe I may be experiencing a little hull crush. I do have a downhaul between the cabin top and mast step. I'm considering a brace between the chainplates blended in with the cabin top interior (ceiling).