The hull is pretty much done but without the deck the hull is a little more flexible than I think is right. I am sure that when I put the deck on it it will stiffen it right up but just wondering what your preference is as far as hulls are concerned. I know if you build too stiff stuff just cracks right up and if too flexible it will handle weird. Going to get the deck material tomorrow and weld in the attach points, do the deck and try it but wondering on your thoughts. Thanks for the help! 8)
-
If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com
How STIFF or flexible is good?
- Thread starter COLD
- Start date
goldhunter_2
Well-known member
I don't like to much flex in any of m hulls except the large flat bottoms
before you weld the deck on post some pictures of your bend shapes and the inside and let me look at it in case I have some thoughts on it
before you weld the deck on post some pictures of your bend shapes and the inside and let me look at it in case I have some thoughts on it
found steel a little different? to work with. I think buying new welder because first off getting to old to haul a steel boat lift out of the lake and old lift wont fit new ski boat, so need aluminum capability. However this should be tough as $hit but couldn't do 1/4" steel 2' T bar or angle so Monique type frame.. Sitting at about 1000 Lbs as it is without deck. Time for weight watchers. Deck will be glassed plywood bolted down with 4 hatches. Fuel tank will stiffen. Stiffer from front but jack rear corner and 3/4" before lifting other rear corner. Pretty sure deck will make that more acceptable. :? Next boat smaller and aluminum! :lol:
by the way! :lol: 10 point jacking capability. I figured just in case I really screw up!! :lol:
jpatter123
Well-known member
good god thats some nice looking work. Can't imagine how long that took.
Just ask my wife, :lol: She keeps bringing up laundry! :lol: Gotta get the top done, flip, 35' of weld, roll with epoxy and 50% by volume graphite (Frog spit or whatever) inside of hull will be done in rubberized undercoat with a shultz gun. Then it can sit outside and I can put the engine together and build an engine stand, (hydraulic trim, still trying for 2600 lbs fueled but overweight guys might need that trim more than others :lol: ) . But gotta get it out of the garage in case something breaks down in the winter. 40 below! Spent the day in the yard because she was ticked I was spending too much time on the boat. Well honey if you break down take care of the details and take a cab to work, no, just give me a chance to get this thing out of the garage honey. Were close! I can probably have all the rest of the welding I need to do as well as pick up materials, do a run to the dump with trimmings I did today, weld fasten points tomorrow, and get ready for glass next time I have an opportunity. I wish I would have herd about Waterthunders 20' barge sooner and gone for a drive! :lol: :lol: :lol:
I guess if time wasn't a factor I only have $1200.00 in this hull including glass, gas,steel , wire, abrasives? lotta work though! :wink:
I guess if time wasn't a factor I only have $1200.00 in this hull including glass, gas,steel , wire, abrasives? lotta work though! :wink:
Daddy Dave
Well-known member
Oil tankers float.....incredible detail work...just don't want to be the rider who has to jump out and break the bow loose....what's the power to be?
Yeah it should float, all the welds are good and it will be decked over and I will have a bilge pump. :lol: No really at 62.4 lbs/ ft cubed it should have 2" of draft at this point. 12 Gauge (0.105"0) steel is pretty much the same weight as 1/4" aluminum and that is what they use for jet boats up here, then they install HDPE or Steel on the bottom of that so it will slide over the rocks. I did the truss work because I went light on the stringers and cross braces. Not much structual integrity there with 1 1/4" flat bar stringers, they are just there for impact stifness. It will be powered by a MkIV 489 CID Big block Chevy with a 2.68 Rotator and a 82" 3 Blade Superwide Sensenitch. I know not many of you are willing to talk about weight but I am targeting Priority1's 460 Ford post as a target!
"I have no idea on what the average air boat weighs, but I had mine weighed and she came in at 2650lbs that's full of fuel and all the other crap I have stowed on the boat. Now that maybe alot I don't know, but a friend of mine has a 14 X 7'6 Diamond Back and a 383 stroker motor and a Belt Box and I came in 100lbs heavier than his. "(Priority!)
"I have no idea on what the average air boat weighs, but I had mine weighed and she came in at 2650lbs that's full of fuel and all the other crap I have stowed on the boat. Now that maybe alot I don't know, but a friend of mine has a 14 X 7'6 Diamond Back and a 383 stroker motor and a Belt Box and I came in 100lbs heavier than his. "(Priority!)
goldhunter_2
Well-known member
hmgm123,
Cold is building a battleship class airboat :lol: I think he said he wants to paint it battleship gray :lol: :lol: :lol:
Josh,
you would be surprised what floats they build actual hulls for larger class yachts and cargo ships out of concrete it's all a matter of displacement figures
Cold,
I do have a few comments . that square tube is probably a little heavy but should tighten up nicely maybe a few more braces for deck support and you can use lighter T bar or flat bars on end like you did for the stringers . T bar is easier to work but the flat bar on end will be stronger then you think . on your bottom stringers of flat bar I would put more 1-2"welds beads I like it leave about 1" in between and stagger the welds as you go. you deck I would just go with something like 16 ga (or little liter) steal sheet.
The flex you asked about is form the hull design and bracing it self, after seeing what you have this would be my suggestion . looking at the bottom and side on the inside where you have braces going to the gunnel's I would suggest making a triangle shape to run along the bottom form the stringer to the side then up to the gunnel and down along the brace back to the stringer. you can use 16 ga sheet metal and cut some holes to remove excess weight form the braces . your braces look bout 18-24" apart so I would put one at each brace location . I would also add some knees like that in the back at least two where each frame section is or one in the middle and one on each side between the frames section and the side. I know that will be time consuming but will really tighten the hull up
Before you deck it, and after you add the braces. I would spray the inside with a good primer once it drys put the hull on some boat stands and level her up , put a garden hose in side an turn it on getting enough water to get above you transom welds bottom 1 1/2" . as it fills you watch for wet spots and mark with a permanent marker in case there are any pin holes that you may not see .
Cold is building a battleship class airboat :lol: I think he said he wants to paint it battleship gray :lol: :lol: :lol:
Josh,
you would be surprised what floats they build actual hulls for larger class yachts and cargo ships out of concrete it's all a matter of displacement figures
Cold,
I do have a few comments . that square tube is probably a little heavy but should tighten up nicely maybe a few more braces for deck support and you can use lighter T bar or flat bars on end like you did for the stringers . T bar is easier to work but the flat bar on end will be stronger then you think . on your bottom stringers of flat bar I would put more 1-2"welds beads I like it leave about 1" in between and stagger the welds as you go. you deck I would just go with something like 16 ga (or little liter) steal sheet.
The flex you asked about is form the hull design and bracing it self, after seeing what you have this would be my suggestion . looking at the bottom and side on the inside where you have braces going to the gunnel's I would suggest making a triangle shape to run along the bottom form the stringer to the side then up to the gunnel and down along the brace back to the stringer. you can use 16 ga sheet metal and cut some holes to remove excess weight form the braces . your braces look bout 18-24" apart so I would put one at each brace location . I would also add some knees like that in the back at least two where each frame section is or one in the middle and one on each side between the frames section and the side. I know that will be time consuming but will really tighten the hull up
Before you deck it, and after you add the braces. I would spray the inside with a good primer once it drys put the hull on some boat stands and level her up , put a garden hose in side an turn it on getting enough water to get above you transom welds bottom 1 1/2" . as it fills you watch for wet spots and mark with a permanent marker in case there are any pin holes that you may not see .
Thanks gold, Same Ideas I had but I agree Jim, I am going to fit the deck first before adding any more steel and see how it looks.
The hull WONT be battle ship grey though! :lol: I am going to coat the bottom with Epoxy with Graphite powder mixed in. It ends up between dark grey and black. I imagine same as "frog Spit" or whatever. Prices out about the same just don't have to pay shipping. 8)
The hull WONT be battle ship grey though! :lol: I am going to coat the bottom with Epoxy with Graphite powder mixed in. It ends up between dark grey and black. I imagine same as "frog Spit" or whatever. Prices out about the same just don't have to pay shipping. 8)
Thanks again gold! Got the rest of the welding done, Bow tubes done and added gunnel braces on the aft X section. Will weld in the stringers like you sugested. They were actually done both side of the stringer so no big deal ading one side staggered. Will just mean 2" welds with 2.5 to 3" gaps. Can handle that.
Angle for cross braces was 1/8" X 1.5"X1.5" for 1 Lb./ft
Flat bar was 3/16"/1.25" for .8 lbs/ft
tube was 1" sq .065" for .827 lbs/ ft
12 gauge (0.105") sheet is 4.375 lbs/ sq. ft.
Don't really see why you think tube is so heavy considering structural advantages? But you have helped me a lot and I thank you!! 8)
Angle for cross braces was 1/8" X 1.5"X1.5" for 1 Lb./ft
Flat bar was 3/16"/1.25" for .8 lbs/ft
tube was 1" sq .065" for .827 lbs/ ft
12 gauge (0.105") sheet is 4.375 lbs/ sq. ft.
Don't really see why you think tube is so heavy considering structural advantages? But you have helped me a lot and I thank you!! 8)
