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System_Error_117

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About System_Error_117

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    Toronto
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    Sailing

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  1. Interesting! Based on my little research it seemed like the triangular bulbs were tempting to generate lift or act as a bit of a bulb wing, where as a true rounded bulb is just the most efficient way of getting the most lead down low as possible with the least amount of drag, and therefore less drag then a triangular cross sectioned bulb per given volume. Like everything in life, its seems there is good and bad to just about any way of doing anything!
  2. So I found this pretty slick righting moment calculator on the Selden website. Its all in mm and kg, but converting is a simple task. Using the original factory numbers for the boat from the sailboat data website, combined with what I know about the modified keel, I was able to calculate what the righting moment before and what it is now, as well as what weight would be needed to get the boat back to that number. https://support.seldenmast.com/en/services/calculators/rm_calculator.html I used the following; Beam: 3860 mm, Draft: 2641 mm (before cutting), Draft: 2133 mm (after cutting),
  3. I agree, the weight added in the floor seemed odd. There was a diagram that showed about 20 bricks, but when I lifted the floor up I only found 5, so someone already might have thrown those over board for the same reasons your saying! A friend did the 800 pound calculation based on the current 4000lb ballast, original 8 and a half foot draft and the 16 inches or so removed. I'd assume we would just need to look at the reduction of lever length, and adjust weight for the same work done on the "load" or in this case "boat". I know there is a bit more to it with center of buoyancy etc., but
  4. So the keel has been welded back together, we lifted and re bedded it last night. Now the shaping can begin! I employed a professional experienced stainless steel welder who was able to back fill the stainless all the way up to the plate surface from the internal I beams based on my angular grinding that allowed the weld to begin at the center and work its way out. Lets just say I cleared our local welding shop out for stainless welding rod, lol. Also after measuring the cross section of the blade, determined it was nearly 3/4 of an inch too narrow based on its width for a proper foil shape, s
  5. Ahoy sailors, I'm in the process of modifying a 1985 Lager 40 on a Laser sailors budget, lol. She was refitted in 1998 with a Brendan Dobroth designed stainless steel keel with a lead triangular ball and matching rudder. She also received a new rig and chain plates to carry more sail. She originally drew 7 feet, and now draws about 8 feet 6 inches. Apparently this actually netted a significant reduction in overall weight getting rid of the solid lead fin keel and moving to the lead torpedo. They compensated by added lead to the sole of the boat to maintain its weight and waterline length
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