I've been towed in a few times and had to tow a few boats myself. The faster speeds my be faster, but also a faster way to get into trouble. Since I am not that experienced as a tow boat driver, lol, I tow like I bbq, slow and low. Between about 10-15 mph. It sure sucks, but never had issues stop the process.

I try to keep a tow rig in my boat for myself getting towed or towing another boat.
1. good 5/8 or larger rope to make Y harness to fasten to the tie down points on transom of boat doing the towing.
2. about 100 ft of 5/8 or larger rope to use as tow rope.

on smaller boats I have towed (duck boats and such) I can usually get them on plane and it makes for a much better experience for all parties involved. Its a long ride from the wax campground to the boat launch. Never towed or been towed in a bay boat very far so I just take it easy. But I think it can be done safely if the boats are similar size, weight ,and conditions allow.

I need a big rope to keep on the boat

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Not really 1/4" Spectec 12 is stronger than 1/4" handrail cable. I have a few buddies who trawl for a living. They take the cable off the winches and use Spectec. I've seen 3/4" used on tug boats to move barges.
http://www.novabraid.com/rope/spectec.html