I’d still like to know where this was.
As your father’s unit was 3,000 men it was a USMC regiment or, in UK / Australian terms, a brigade.
The Marine division that figured in Admiral Nimitz’ plans for the Gilberts was organized according to the E series tables of organization adopted in April 1943. With an authorized strength of 19,965 officers and men, the division was constructed in a triangular fashion–three infantry regiments, each of which had three infantry battalions. This arrangement enabled the division commanding general to hold in reserve an entire regiment without impairing the ability of his command to attack or to remain on the defensive. A regimental commander could exercise this same option with his battalions, and the battalion commander with his rifle companies, as well as with a headquarters company and a weapons company. An infantry regiment was authorized a basic strength of 3,242, a battalion 953, and a rifle company 196.
http://www.ibiblio.org/hyperwar/USMC/III/USMC-III-I-3.html
You’re talking about a rounded 100% death rate for that beach landing, wiping out a regiment. There isn’t even one Pacific beach landing with a rounded 100% casualty rate that I know of, at regimental level or even battalion or company level. I can’t even think of an island campaign that had an effective 100% casualty rate, let alone an effective 100% death rate, at those unit levels.
Tarawa probably had the worst USMC casualty rate in the initial beach assault, but I cannot find any reference to about 3000 dead on a beach in the first wave. Or, for that matter, in several waves. Tarawa casualties were in the thousands only if measured in days, not the first beach wave. And we’re still not talking about deaths.
If there was a USMC action with only 4 men left alive out of 3,000 in the beach assault it would probably be the USMC’s biggest event, and it would be remembered and comemmorated by the USMC. It isn’t.
I can’t find any reference to it, nor have I ever heard of it. So, where did this happen?