Yes I personally know someone that has successfully claimed housing benefit.
He's had two claims in different parts of the country. In the first he managed to claim licence fee, 3rd party insurance and boat safety, at the time he did NOT have a permanent mooring.
In the second he gets licence, mooring, 3rd party insurance and boat safety. As he has a kid aboard he also got social services to spend £5k fixing various bit on the boat, new cooker, new shower, replacement water tank were the key things.
Key thing is , never give up, if your claim is rejected appeal, if your appeal is rejected submit a new claim, make sure they give up before you do!
Rik