I used all of my 25’ of chain and backed the tow vehicle up to the hubs to get my boat deep enough to float. Consequently I do not think a tongue extension of that length is workable. I believe the best answer is the Meriachee dolly wheel and 30’ of chain. I think it would work safely in almost any situation. The wobbledicky wheel worked for me this time but It was on a smooth asphalt road and I still held my breath several times. James