Aluminum Hull
Aluminum Hull
(OP)
Is aluminum a good material for a gun boat hull? Wasn't that type of material used on a British gunship sunk by the Argentinian Air Force during the Falklands Island dispute?
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RE: Aluminum Hull
As for the HMS Sheffield: http://
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RE: Aluminum Hull
Are you mainly concerned about aluminum regarding its resistance to munitions, or some other specific criteria?
RE: Aluminum Hull
The stand-off distance was at least 1.5 km, ensuring that only cutters and larger would be a threat, and at that point, you're better off bailing than fighting.
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RE: Aluminum Hull
"Art without engineering is dreaming; Engineering without art is calculating."
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RE: Aluminum Hull
http://www.defensenews.com/story.php?i=4446438
Anyway, there were indeed reported problems with the aluminum structure on some Royal Navy Vessels in the Falklands war. Though at least some of these appear to have been discredited. Look up Sir Galahad & Sir Tristram - the latter was severely damaged and when rebuilt it was done with steel instead of Al.
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USS Belknap is one poster child of aluminum fire damage concerns.
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There's a lot of information on the web about this, though you need to sort through the military fan sites etc.
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Al was originally used on military ships to save top weight. I'm not sure why it wasn't used more for Mine Counter Measures Vessels where GRP seems more popular. Being non magnetic should be an advantage it shares with GRP though being conductive I wonder if Al hulls are prone to still setting up electro magnets.
What is Engineering anyway: FAQ1088-1484: In layman terms, what is "engineering"?
RE: Aluminum Hull
KENAT is correct. Most US Navy ships do not have aluminium hulls. I think composites will be the material of choice for future ships.
RE: Aluminum Hull
However, under certain conditions of elevated temperature exposure, alloys containing higher amounts of magnesium (>3%Mg) may become susceptible to intergranular forms of corrosion (i.e. intergranular corrosion, exfoliation, and/or intergranular stress corrosion cracking). Exposure to certain unsuitable combinations of time at elevated temperature (>150 degrees F) either during the fabrication of the sheet and plate products or in service can cause precipitation of the b-phase (Mg2Al3), which forms preferentially on the grain boundaries. The b-phase precipitate is electrochemically more active than the aluminum matrix and the susceptibility of the 5XXX materials to intergranular forms of corrosion increases with the continuity of the grain boundary precipitation.
Require producers to perform nitric acid mass loss testing (ASTM G67) to verify that the material is resistant to intergranular forms of corrosion. Consider using hull material Aluminum Alloy 5083 and Aluminum Alloy 5454 for higher temperature compartments .