> Boat legal width limitation is 8 feet 6 inches.
> Boat Legal height limitation varies by each state. Base measurement is Total height of 13 feet 6 inches loaded onto the trailer.
> Boat Legal length limitation of a single vehicle operated under the vehicle's own power is 40 feet;
> Two-boat combinations vary by each state. Base measurement is 60 feet, with a 53-foot limit on the semi trailer.
> Three-boat combination is 65 feet, with a limit of 28 feet 6 inches for each semi trailer and trailer.
> Legal weight limitation varies by state, subject to all individual axle weights conforming to the Federal Bridge Formula.
The pre-defined limitations for a Yacht Transport Permit are as follows with variations between states:
> Width varies by state.
> Height varies by state.
> Length exceeds varies by state
> Weight exceeds varies by state
> Non-divisible load factor with substantiated application to DOT for each state.
In general, yacht transport that exceed these dimensions and weights will require additional efforts, engineering judgment, and coordination between the yacht transporter, DOT, District Offices, and local authority for each state.
What I read is 13' 6" is max for local states, interstates are 14'. But that is without permits, with permits and route planning you can go higher and every state has different rules. That is all included in the price you pay.