Triple Axle vs. Duallys
 

What are the pros and cons of a triple axle trailer (let's say a 30' - 50' boat)? I saw a picture of a set of duallys on a 38' Fountain trailer and was just curious.

Typically, a set of duallys will cost more initially, but will experience less tire scrub while maneuvering tight turns. The triple axle will be less initial cost, but will scrub more in tight maneuvering. The twin duallys will take more weight, but the triple axles are more than adequate in most applications.

I think the OP is referring to a tandem axle setup with dual tires on all four corners, so eight tires; like this one:

[ATTACH=CONFIG]505599[/ATTACH]

Typically, these are made from semi-trailer hardware and are not really designed for dipping. I'm sure that someone will post they do it all the time; and that's fine as I imagine you could have it set up to do so. The biggest difference in these type of trailers is that they sit the boat higher. This means you are going to need more (deeper) water and a longer ramp to get the boat to float, if you launch traditionally. In this case, I would be concerned about the trailer falling off the end of the ramp since your most forward axle is probably located 12-18" further aft than a typical triple axle trailer.

Double Dually axles use stronger components. Normally they do come in oil bath but you can get grease hubs, or just drain the oil and pack with grease. The brakes are larger, and electric over hydraulic is more common on these 10,000lb and larger axles. IMO these axles are best suited for Heavy Equipment Trailers not boats.

BUT

The real Ticket and I am surprised the Boat industry has not caught on....running Super Singles on the Double Dually set up. Properly set up most boats could run Tandam 10k Super Singles and be LOVING Towing. You could also run Triple 10,000lb+ axles if you really want over kill. Then you get better axles, brakes, tires, wheels, etc with the lower boat height. Some of the 250k Tilt trailers hauling the big cats run Triple super singles.

Most boats on this site could have a trailer built that tows better then their current triple axle with Tandam Super Singles 10k+ axles.

I do love triples though.

That was the picture I saw and was describing. Good input, thanks everybody.