Alan H

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About Alan H

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    Super Anarchist

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  • Location
    SF Bay Area
  • Interests
    Shorthanded Sailing

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  1. Alan H

    E-nav on the cheap

    Eh? Open CPN on linux? I dinnae know this. And here I was going to run in on MS Vista. Seriously. Vista.
  2. Alan H

    H-Boat Renovation Project

    Mine did too. I thought it was some bizarre vang purchase thingamabob.
  3. Alan H

    putting in a keel lifting point

    Anyway, the S2 7.9 is supposed to weigh 4,000-4200 pounds. Somewhere in there. It's got a 9 foot beam. The Piper weighs 3500 pounds with a 6' 3" beam. My lifting framework actually splits in half so it's easier to store on the trailer. I can just cut the center pieces on my current frame and make it 6' 8" wide and it'll work fine. I could take off the four preposterous prestretched dyneema pieces and replace with four double-ended double-layer nylon slings @ $17 each I re-use the shackles and lifting ring....or if the clearance is enough, I use the dyneema. I'll just have to re-size the straps that go under the boat.
  4. Alan H

    putting in a keel lifting point

    And a couple of Piper OD's sailing off the Royal Gourock YC...
  5. Alan H

    putting in a keel lifting point

    Once upon time I wanted to dry sail my S2 7.9, which many of you know, has a lifting 600 pound daggerboard. The Alameda Marina has a 3 ton hoist with two choices of spreader-bar systems. I knew that, which is why I bought the boat. Not three months later came the news that Bay West was going to develop the Marina. I went ballistic, wrote letters to the newspaper and got evicted. so much for launching at Alameda. So I tried the only other working 3-ton hoist in the Area, at Brickyard Cove. I made up the steel framework and showed it to the harbormaster. He said..."Your system has to be approved by **that rigging guy over there**, and we'll try it and I'll see if I'll let you launch this way." So I went to that rigging company who will remain un-named. I COULD HAVE made the bridle out of four, two-ply nylon eye-and-eye straps rated for six fucking thousand pounds EACH and cost $17 each. Or yanno, could have made some 6-foot long s.s. cables, swaged together for a hundred bucks. But NO....no, my lifting bridle cost me over $600, as it was made by the rigger who was required to approve my setup. It's spliced and prestretched dyneema, for fucks sake. Because you know, we must have THE BEST. And then when it was all done the overhead clearance on the whole thing was about nine inches too much. I couldn't get the hull over the safety railing. I spend almost $1000 on a lifting bridle and it's sitting in my garage doing absolutely nothing. I sold the trailer and wet-sail the boat out of Coyote Point, which in the end might have been a better idea, anyway as it's 25 minutes form my house. The clearance on the Brickyard Cove host 4500 pound hoist is about 13' 6". The clearance on the Alameda Marina 3-Ton hoist is over 16 feet. I dunno what the clearance on the TI Sailing Center hoist is. Anyway, a 6' 6" spreader bar out of 2 x 8 rectangular box steel is about $100 in materials and $75 in welding labor. Here's a pic of a Piper OD launching with a loader at the Holy Loch YC.
  6. Alan H

    putting in a keel lifting point

    I actually have a frame and straps, that worked for the S2 7.9, and this boat is 500 pounds lighter and almost three feet narrower. I could trim two feet out of the port-starboard tubes on the frame and stiffen it up. I'd probably need to make at least one new strap, Problem is, the TI Sailing Center guy says "single point lift only". But that's rapidly not becoming an option. Launch ramp. Oy, ve.
  7. Alan H

    putting in a keel lifting point

    Oh FML. Never mind. Just got this from the class historian. "Hi Alan Read the story in the book about the lead. It's not poured. They are blocks with glass gunk fill. Bolts right beside the existing lift points might be ok. But we all use slings."
  8. Alan H

    putting in a keel lifting point

    There are no keel bolts in this boat. The keel isn't "bolt on". It's an Old Skool full-keel boat. Here's a pic of a sistership hull I've done a little reading. Withdrawal force needed to yank two identical bolts out of different materials depends on the tensile strength and shear strength of the material into which the bolt is embedded. So...question is, what's the tensile and shear strength of lead, compared to concrete, since the bolts I'm talking about are designed for concrete? Looks like concrete shear strength is 6 - 17 MPa, whatever "MPa" is. Tensile strength is 2 - 5 MPa...also expressed as 300-700 psi https://www.engineeringtoolbox.com/concrete-properties-d_1223.html OK, cool...how about lead? - https://www.ila-lead.org/UserFiles/File/factbook/chapter2.pdf Pure lead tensile strength is 12 - 17 MPa. It's about 1/6th of aluminum. The range overlaps that of concrete. However, even a 1% addition of antimony pushed the tensile strength to 23-25 MPa. So in other words, while lead "creeps" and concrete doesn't (much) and while concrete is killer strong in compression, in terms of tensile strength and shear strength, lead is stronger than concrete. SO..in theory, a s.s anchor bolt set into lead should in fact grip BETTER than it does in concrete. Measurement units are confusing. Grrr. According to this reference, which uses different units, then tensile strength of lead is 2,000 PSI. - https://mysite.du.edu/~jcalvert/phys/lead.htm#Prop And according to this - https://civil-engg-world.blogspot.com/2009/04/relation-between-compressive-and.html : "Commercial production of concrete with ordinary aggregate is usually in the 3,000 to 12,000 psi range with the most common ranges for cast-in-place buildings from 3,000 to 6,000 psi." So one reference says the tensile strength of concrete is 300-700 psi and another one say it's 3,000 to 6,000 psi. if I pick the worst-case comparison of concrete being 6,000 psi, and lead being 2,000 psi, then I suppose I might be able to say that the withdrawal strength of a bolt in lead would be 1/3rd that of what it is in concrete. if that was the case and I set up two bolts anchor, each of which is rated for 9,000 pounds in concrete, then it COULD be that those bolts would only hold to 3,000 pounds in lead. Two of them make 6,000 pounds of holding power, supporting a 3500 pound boat. I would wish for more but that's probably doable. I still want to hear from engineering gurus.
  9. Alan H

    Ultralight windvane selfsteer project

    SWEET!!! How does it work off the wind?
  10. Alan H

    putting in a keel lifting point

    Oh. Well #$%^&*(. --- 4,000 PSI concrete is just regular old concrete. https://www.doityourself.com/stry/mixing-4000-psi-concrete It's freaking Quikcrete...https://www.whitecap.com/shop/wc/p/quikrete-ready-mix-4000-psi-concrete-60-lb-1101-60 OK, that can NOT be stronger than poured lead. No way.
  11. After mulling over some options, I think I'm down to the point of needing to sink a couple of J or L-shaped stainless steel bolts into a ton of lead so that I can pick it up on a hoist. There's 2100 pounds of lead in a 3600 pound boat...that's the load we're talking about here. Gut feeling is that drilling four 12-inch holes, tapping 'em, and cranking a couple of bolts in there might not cut it. I suppose that I might drill a pretty good hole, pour epoxy into it and then use an industrial-strength s.s. expander - wedge anchor like this : https://www.grainger.com/product/DEWALT-ENGINEERED-BY-POWERS-10-Stainless-Steel-Expansion-448L72 or this: https://www.fastenal.com/products/details/2140569 but I dunno if four of those is gonna hold 3600 pounds. That''s 900 pounds each straight-line withdrawal force and God Forbid that the hoist goes *bump* and loads it to half again that for a second. But WTF do I know? Hey Wise Engineer folks, what do you think? This is ONLY for lifting the boat with a hoist, the lead is internal inside the hull.. HOWEVER..there's this: http://catalog.fmstainless.com/viewitems/expansion-anchors/stainless-steel-sleeve-anchors-hex-nut- Which basically is a chart for s.s. sleeve anchors set into 4000 PSI concrete. How that compares to lead??? http://catalog.fmstainless.com/viewitems/expansion-anchors/stainless-steel-sleeve-anchors-hex-nut- I'd think that concrete wasn't anywhere near as "crumblyproof" as lead. However, according to that chart and 3/8 x 4 set in concrete should hold well over 3,000 pounds. If I went up to 5/8 x 4.25, and set two of them into the lead...if lead was the same strength as concrete, then that would be 18,000 pound "strength" whatever that means. I think that's a safe margin for a 3600 pound boat. My gut feeling is still that the expanding bolts ain't gonna work. It's cause I don't know shit so I'm a'skeered. THAT means somehow sinking 2 to 4 , 1/2" or 5/8" 304 s.s. L-shaped anchor bolts into the lead. I can think of two ways to do this...heat the bolts to "damn hot" but not hot enough to mess with the temper and slowly press them into the lead. The other way is to drill/cut, melt..whatever a deep groove into the lead and shove the bolts in there. Then heat the whole area with a torch and pour hot lead in over the base of the bolt, leaving about 2 inches standing proud. Talk to me, oh cognoscenti.
  12. Alan H

    H-Boat Renovation Project

    That's one clean H Boat.
  13. Alan H

    Piper OD .. dayboat

    Ha ha!...NACA section on this rudder? I don't think so!
  14. Alan H

    Piper OD .. dayboat

    Now I have some reading to do, to figure out how to build the rudder for this thing.
  15. Alan H

    Piper OD .. dayboat

    BOOM! Made an offer...he counter-offered. Got it. SWEET! Apparently the trailer isn't capable of getting the boat down here from up in Nevada City. That's the bad news. The good news is that another guy I've been communicating with, who knows his shit, has tapped the deck and hull and found no delamination. Delammed decks are the primary bugaboo with these things. SWEET. I've got another rudder to make! LOL