Standing Rig Loading Question

[pkrogh]

On page 137 of the Apprentice there is a Formula for determining shroud loads. When I put in the numbers for my boat and turn the crank the following numbers fall out:

Lower shrouds 1,125 lbs. and Upper shrouds 1,687 lbs.

My boat: Clipper CM/4c

LOA 23-7, LWL 18-6, Beam 7-11, Disp. 2,000 lbs., Ballast (swing keel) 540 lbs., Mainsail area 78 sq.ft., Jib 105 sq.ft., Genoa 181 sq.ft.. IJPE of 25.00' / 10.17' / 20.92' / 7.58'. Wire size is 1/8" and pin size is 1/4". Forestay, backstay, two lower shrouds per side and one upper (with spreader) per side. Chainplates are quite stout made of SSTL and mounted with three big bolts (and backing plate) each.

Can the loads really be this high? Have I messed up the calculation somewhere?

Thanks,
Pete