I have a question about stability.
i have a landing craft and am about to install Spuds, like a spud barge. But the company I’m working with has over built the spuds that are going to go in.
I need some help with stability math.
here are the specs on my vessel… It’s pretty much a square…
length 56’
beam 14’
displacement 66 tons
Unloaded draft 2’
4 spuds, one for each corner…
each spud is 20’ long
constucted out of 11" box tube, 3/8" steel
sheething is 12" box tube, 4’ long, mounted from the water line up.
freeboard is 4 to 5’
the vessel is a LCM 6, landing craft.
what kind of formulas do I need to look at?
are these spuds way over built? What is a safe margins to work with?
[QUOTE=Greenmtmarineservices;181229]what kind of formulas do I need to look at?
are these spuds way over built? What is a safe margins to work with?[/QUOTE]
but what is it that you want to know? will the thing roll over when all four spuds are winched up? we can’t answer that with the info you have provided. do you know the lightship KG even? if we had that, the rise in KG with the spuds up could be estimated but without that all that can be said is that the center of gravity will go up. To counter that it will require cargo or ballast. Nobody who is a professional would dare to ever say safe margin with this info. You need a naval architect and an inclining experiment to know what is safe and what isn’t.
No substitute for a naval architect, but keep in mind you don’t always need the spuds up all the way…you’d have say 12’ above deck if you let them hang 4’ below the bottom. Don’t see why you need 4 spuds though anyways. That isn’t a lot of beam or depth for spuds of that size and number in my mind.
You should be fine, I’d go with 2 though. Do a google image search “waterfront construction Justin” they have the same lcm with 2 spuds here in Seattle.