I have one slightly used Rod Holder Tree.
This Bert's Custom Tackle Rod Holder Tree holds 3 rods of any length with an additional rod or net holder on the top. This tree is the ultimate rod holder for dipsy rods, board rods, downrigger rods and reef rods. This one does not swivel.
Rod Holder Trees can be mounted in as small as a 6" Bert's Track System (sold separately) on either the Port or Starboard gunwale of your boat. The rod holder is constructed of stainless steel and anodized aluminum.
Price is $99 plus UPS ground shipping which should be under $25.