Rig and Spar Design and Engineering
Naval Architecture involves hydrostatic studies of powering and resistance, stability, control and handling, and motion; materials science and structural engineering. This includes alterations to change trim, stability, and powering or sailing performance. Most of my naval architecture work falls into these areas:
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Sail: Rig and Spar Design and Engineering
Rig and Spar Design and Engineering
We have done a number of these including engineering a new mainmast for the Canadian Navy sailing vessel Oriole, designing a cutter rig for a Kettenburg 40, a new rig for a Cape George 31 including mast design, and a two spreader rig wooden spar and rig for the Swain 36.
Engineering a new mainmast for the 102' (31 m) Canadian Navy sailing vessel HMCS Oriole: In the case of Oriole’s new mainmast, it was a replacement wooden spar, but we probably saved 100 pounds with a new aluminum masthead fitting.
Changing the rig or even revising the existing rig can transform a boat into something new. In one case I re-designed the rig and deck hardware layout in a Kettenburg 41, changing her from a sloop to a cutter. In the owner’s view this made the boat far more manageable as when the wind increased they just rolled up the jib and proceeded under main and staysail. In other cases I have designed new, lighter rigs which make the boat faster and stiffer.
Currently, we are consulting on a new rig for a 50' Frank Fredette sailing troller.
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We have considerable experience with classic and traditional sailing yachts to 154', with expertise in rigging and deck design, spar and rig engineering, and deck layout for efficiency. We were recently consulted on rig changes to Whitefin, a 90' BKYD sloop.
New sailplan for the 1927 Urry Brothers' cogge ketch
Two spreader wooden spar and rig for the Swain 36Tad on Designing a Wooden Spar
Every material can be bent or distorted a certain amount and still spring back to its original shape. Every material also has a limit of loading beyond which it will be permanently distorted (bent or broken). This is referred to as the Elastic Limit, the usual symbol for this is E, and it’s a number in psi or Kilonewtons/mm2 or Gigapascals (GPa). For example:
- E for Aluminum is 10 * 10^6 = 10,000,000 psi
- E for Sitka Spruce is 1.57 * 10^6 = 1,570,000 psi
- E for Douglas Fir is 1.95 * 10^6 = 1,950,000 psi
- E for Red Cedar is 1.12 * 10^6 = 1,120,000 psi
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Power: Masts and Stabilizer Poles, Auxillary Sails
Spar and rig design also includes masts and adding sails or stabilizer poles to power vessels.
- Read more on the Stabilizer Systems and Auxillary Sails page >>
