They will need every one of them to defend the Leviathan and Tamar fields.
Much Dolphin info here:
http://www.defenseindustrydaily.com/germany-may-sell-2-more-dolphin-subs-to-israel-for-117b-01528/
How did they manage to move the city of Kiel 60 miles inland to Hamburg? (Answer: they didn't. It's the HDW shipyard in Kiel they are referring to.)
i honestly think that in theory, there should be no reason for the US to have to get involved. God is looking out for the people of Israel, i feel in theory that should be more than enough.