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Hi Folks,I have had a couple of other threads, with specific questions. But, thought I would start a general thread to show progress.Have most longitudinal stringers (3/16" x 1 1/2" x 20' 6061 flatbar) in place on hull bottom, and am now bending the ones on the topsides, which have more of a bend near the bow. In one pic you can see I broke one stringer ( it had been tacked/heated, then ground off, tacked again/reheated and it broke while bending a second time) I am having some trouble deciding how much to curve the stringers upwards (really downwards as boat is upside down) as I bend them in to meet the more narrow frames 7 and 8 near bow, and finally to touch stem. The plans say (on forward stations) to try to position the stringers / side stiffeners roughly evenly spaced between chine and sheer. It seems though, that as I bend the flatbar against it's strong side- it "likes" to sweep up (really down) some near the bow. But, this would mean that near the bow the spacing would be closer to the chine and not evenly spaced between the chine and sheer. You can see in one pic that I have cut a couple of slots in the side frame, in order to try bending while changing the position a couple of inches.I have only tacked enough stringers to keep frames level and at the proper distances from each other. The plan is that one the hull sheet is in place, I will look under and see if some stringers have high / low spots, and then I would cut the tacks and adjust appropriately. Then weld all/ most stringers to the hull sheet before welding the stringers to the frames.As always, I would appreciate any help / advice!I have been in contact with an experieced local aluminum welder, and am hoping to get him to stop by for a few hours, in a couple of weeks, to check work and help me improve technique. Attached Images
Reply:Good progress few things I do diff are don't tack the. Stringers to the bow stem when you go to weld They get in the way also they can and do make it harder to pull your bow together. Did you have the plates cbc cut or are you hand lofting? Put all the stringers in its unbelievably hard to put them in later and I don't see a transome or stern plate those will help keep your boat hull level and square and gives you a point to measure too . The stringers I tend to over bend them slightly I usually use tbar though just help with the side to side but when you go to pull your plates down you can generally eye ball your stringers straight.Last edited by abec; 03-10-2014 at 12:53 PM.
Reply:thanks for tips. I will leave the rest of the stringers loose from bow stem.No transom yet. Read somewhere that somepeople leave them off for access and add later. Thought of maybe adding a plywood mockup, mayby even with flatbar around perimeter, to tack to, then adding sheet to it later. Haven't decided on size of hull sheet yet. Didn't want to special order transom material.No cnc. I haven't read my Aluminum Boatbuilding book in a while - left it at the cottage. I ordered "full size plans" but was naive, as they were just full size patterns of the frame (half size really). Anyway, I plan on using roofing paper or similar to make templates of separate pieces for hull bottoms, top sides and then lay them out on floor to see what size sheets I should order. I will leave say 1/4" extra as to not have them too small. Local supplier only stocks 4'x8' and sometimes 5'x10' in 5052. I can order larger like 5'x20' in 5052 or 5086, but have pretty big 'roll change"charges, as those sheets are cut from large roll as ordered (not locally). Plans only call for 1/8" sheet on bottom, sides, transom (reinforced with flatbat bracing) and deck. i know some have advise me to go heavier, at least on bottom running surface. But the design/build notes recommends against this and states if anything, add more stringers to make stronger, not heavier sheet/plate, due to weight. Also, because of roll change charge, would like to stick to one thickness for large sheets. Could always get small 4x8 sheets of another thickness if that made sense.Any advice on this is appreciated!Last edited by Northeaster; 03-10-2014 at 01:16 PM.
Reply:Yeah the jigs I use to build the hulls are at least 3ft off the ground so I can stand under them and work with out crawling makes it easy. As for bottom thickness we use 5/16inch for the hull and chines with 3/16 side plates but that's use the legend boats and a few others make there whole hull out of .100 Alu it really depends on what you plan on doing I built one 25ft hull that's got ruffley 8000hrs on it and it still hasn't had a leak or crack anywhere and it's run in the ocean all it's life. Where lucky here the suppliers stock a lot of longer sheets if your local guy doesn't have it maybe see what it would cost to get some shipped from another location over going through him
Reply:I can raise my jig up, so that will come in handy later. I can buy longer sheets direct from Yarde Metals in North Eastern US. Last time I looked I could easily save $1000 up front, but by the time I drove 10 hours each way with a big trailer, it would not pay. Didn't look into having them ship it, as I am not sure about border / customs, but it may be worth exploring.Lower Canadian dollar doesn't help either way. |
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发表于 2021-8-31 22:36:03