Yep I agree ..
Why did build a roofed tunnel when they were very adept at tunnelling.
Cutting out roof rock and then just having to replace it with roof blocks.
It would make sense if they needed to bury the boat in one piece, but they didn't..
The pit isn't big enough.
Is it that they were incapable of cutting out a large enough pit?
Is it that the roof blocks were placed before the boat bits?
Were the boat bits walked in through the end by removing the small key stones?
Was the pit dug for a boat burial in the first place?