Baggy Wrinkles

Baggy Wrinkles
S/V Nautica, Hull #614, Built at Whitby Boatworks Ltd., Ontario, Canada 1977, one of the most recognizeable Carl Alberg designs. A masthead sloop displacing 9000 lbs, keel hull, Yanmar 15 hp diesel, LOA 30.27 Beam 8.75, Draft 4.29, roller furling headsail, tiller, berths for 4, interior teak bulkheads, teak cap rail and cockpit teak coamings, 12 volt lighting, aluminum mast support, Harken self tailing winches, in its day was designed for customers as a Cruiser-Racer, the Alberg 30 remains a Classic design of the large Alberg inventory.

Pageviews since BaggyWrinkles started:

Wednesday, September 25, 2013

Our sailing season is getting better, finally.  With autumn, the south becomes delightfully cooler and bracing cold winds up north manage to push their way into our warmer climate with great frontal waves of cool air.


 
And with that anticipated wind, I am following my fellow Cape Dory blogger Get Kraken by installing a door brace underneath the mast step tabernacle, inside the cuddy cabin, which will connect the pressure of the mast to the keel below once fitted.  I searched and search to find the exact same bracing device and finally found it at a True Value Hardware store of all places! 



I'm certainly not a marine engineer but I can see the difference in shroud tension which occurs under sail in 10 to 15 kts of wind.  The leeward shrouds, both upper and lower, become substantially looser to the extent that I determined these shrouds, taut, but not tight, while at the dock, must have been given this slack by the downward pressure of the mast on the cuddy cabin.  As the wind puts pressure on the mainsail and the genoa, connected about 3/4 up on the mast ( thus a fractional sloop design ) the mast incurs the burden of wind and pushes downward on the vessel.  If the mast base were connected firmly to the keel, as in most larger vessels, the boat would then handle the wind better and would transmit the added wind pressure properly to the shrouds.  I don't know the technical formula for all of this but I see the results every time I sail.  I would be extremely happy if a reader is a marine engineer and can parse this in terms of a formula and insert it in the comments below.

However, in this digital world, one can jump into a sophisticated mathematical set of formulas sufficient to choke even the bravest of sailors.  Try finding the formula necessary in this article I found on Wikipedia:  http://en.wikipedia.org/wiki/Forces_on_sails 

Anytime I see diagrams like this I cringe and remember a terrible history of my encounter with Algebra I over several years in school.  But, I am sure there are some smart sailors reading this who can decipher this sort of information and pour it out rather clearly for the rest of us.


Rather than attempt to make this complicated and work toward simple, I think I'll keep my plan at simple and go for the short solution:  extend my mast to the keel in order to stiffen the mast and create a more effective sail plan to handle the winds.  Once the brace is in place, it should remarkably change both the slack in the leeward shrouds, while at the same time, improving speed over ground of the Dory, and providing more responsiveness at the tiller.

After all is said and done, the view of the helm will still be like this one taken earlier this year on the lake.  However, when the wind gains strength against her she should be able to produce a better result under pressure like most things in life, a little tuning helps when the storms arrive.  Sounds like a life lesson!