I have a few adjustable rod holders suitable for flush or rail mounting. These came from a shop that used them only for display of rods or rod & reel combos so they are technically second hand but have never been used in the field.
This professional rod holder is designed for light trolling. It easily fits to a boat by a rail, side or flush mount and can be adjusted to give just the right angle to fish your lure properly.
Made of Corrosion Proof Polypropylene
Has Rotating Locking Ring
Fully Adjustable Horizontally & Vertically
Can be Rail, Side or Flush Mounted
Comes with 4 Stainless Mounting Screws & Nuts