You need a freight forwarder at the port. Usually the buyer would arrange from his end and all charges in the US and on to the destination would be his responsibility. Get your money up front.
Bob: I've done this several times both with cars and chassis and I have always put the responsibility for the shipping in the buyers hands.
It might be less expensive and more secure to obtain a 20' shipping container to send the chassis. Then book passage with a shipper. I dont know if that would work for you in this situation, just something to consider? Some fellows here did this. It worked out well with shipping a complete vehicle abroad. Containers are cheaper near ports.
Bob I recently sold a 32 roadster to a guy in England, had him do all arrangement. It's a PIA to do it on this end.
A container would be best. In 1994, when returning from England, I shipped 7 Minis in a 45' container. I went thru Maersk and did door to door for just under $3000. We loaded and unloaded. I handled everything since it was my cars, but the buyer is the one that should set it up.
Several years ago I sold a pair of NOS big truck fenders and a hood to a guy in Norway. There was a guy in PA IIRC that owned a speed shop and he would ship containers to Europe with old car stuff on a regular basis. The shop owner sent a transporter to pick up the parts and that was it. Easy peasy.