The best replacement for outboard is inboard.

The best alternatives to outboard are rated as following:
★★★★★  inboard
★★★  sterndrive
★★  i o
★  inboard motors
★  outboard
★  inboard outboard
★  inboard boat motors
★  inboard motor
★  surface drive
★  jet drive
★  4 stroke
★  io
★  trolling motor
★  inboard engine
★  mud motor
  inboard boat
  i/o
  i\/o
  plugins
  yamaha outboard
  inboard fuel economy
  i o motor
  jet boat
  stern drive
  2 stroke
  outdrive
  jet
  two
  yamaha
  diesel inboard
  sterndrive boat
  inboard sailboat
  mercury
  inboard for skiing
  inboard boats
  inboard boat motor
  4 stroke outboard
  inboard\/outboard
  inboard gas mileage
  inboard fuel consumption
  honda outboard
  outboard motors
  johnson outboard
  inboard outboard motors
  twin outboards

Your alternative for outboard is not listed? Suggest!
Speaking about outboard, one probably shouldn't forget about inboard.

Other search terms related to outboard and their ratings are:
★★★★★ inboard
★ power tilt and trim
You have in mind a companion for outboard and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of outboard in all years. Click on graph for more.
outboard
inboard
sterndrive