I need your advice (cf. my questions below), so I will shamefully admit to a somewhat similar problem I had last summer. I didn’t exactly drive into the sea, I wasn’t even on a beach - a good 100 m from it, in fact. But there was a pool/ford there filled with salt water, from the sea having entered deeper inland during a winter storm, then not evaporated completely. It was small and hard ground to begin with, but then exactly the same problem as this poor guy - minus, luckily, any waves. I got stuck and had to be towed away.
I kept the engine running all the time. The front of the car kept sinking in deeper and at one point
the water went up to within 1 or 2 inches of the air inlets, at which point my LR4 smugly informed me that it was lifting itself to a super-high position (taller than offroad mode, did you even know it had that in it?). So I don’t think any water got in, unless very small amounts from ripples created by us walking around the car. A litre or so may have got into the passanger compartment (pedals area) after I’d closed the door too dynamically (the water was below the doorline when I opened it).
After getting out, I drove back to camp (15 mins) and let the engine run for another 5 mins or so. At one point, it sputter slightly and I switched it off. But a few hours later, it started fine. I later hosed the entire car and chassis with sweet water and let it dry for 2 days in hot summer weather.
I have driven it ever since without any issues at all.
My questions are, should I worry about any long-term corrosion problems nevertheless, either in the engine bay or in the cabin, below the pedals/driver’s seat? I know LRs are factory protected against corrosion, key parts insulated etc. I have had the car lifted and inspected since, no corrosion in sight on the chassis. But I’m worried about the cabin, should I get the lining removed and the floor checked? Or am being paranoid?
I guess the guilt feeling is haunting me - or call it shame. I was exhausted to the highest degree when that thing happened. No alcohol or other intoxication but I just wasn’t thinking straight, else it would have occured to me to inspect the entire ford on foot before driving into it...