The stern is the rearmost part of a boat, the end opposite the bow. Anything toward it is aft, anything behind it is astern, and the sides of the hull as they approach it are the quarters. A beginner needs to know that the stern is where the helm usually sits and where the boat is steered from; an experienced sailor knows that the shape of the stern says more about how a boat will behave in a following sea and on a downwind leg than almost any other feature of the hull.
Anatomy of the stern
- Transom: the flat or gently curved surface that closes the aft end of the hull. It may be vertical, raked forward or aft, or reversed, and on many modern boats it folds down as a bathing platform.
- Counter: the overhanging portion of the stern above the waterline on traditional designs, which lengthens the sailing waterline as the boat heels.
- Quarters: the port and starboard sides of the hull between the beam and the stern. “On the quarter” means roughly 45 degrees abaft the beam.
- Rudder and stern gear: the rudder stock, the propeller shaft and, on a transom-hung rudder, the pintles and gudgeons.
How stern shape affects sailing
A narrow canoe stern or a fine counter parts a following sea gently and gives a soft motion at anchor, but it carries little volume, so the boat squats as it accelerates and is slow to plane. A wide, flat stern with the beam carried all the way aft provides enormous form stability when heeled, resists the bow-down trim that comes with a spinnaker up, and lets the boat surf and plane at moderate wind speeds. The price is a boat that heels and then stops heeling abruptly, slams more when pitching upwind, and can be more prone to broaching if the rudder loses grip when the wide stern lifts.
From the sailmaker’s side, stern shape changes what we design. A wide-sterned boat that planes wants flatter, more powerful downwind sails and a mainsail with a leech that can be opened quickly, because the boat will accelerate in a puff rather than heel. A heavy, narrow-sterned cruiser needs fuller sails that build drive at lower speeds and a wardrobe biased toward keeping the boat moving rather than surfing.
The stern and seamanship
Following seas arrive at the stern, and how the boat handles them is a matter of hull form and helmsmanship. Steer slightly across a big breaking crest rather than square to it, keep speed up so the rudder bites, and reduce sail before the boat begins to surf uncontrollably. A drogue streamed from the stern can slow the boat and keep the stern to the seas in survival conditions. Stern-to mooring, common in Mediterranean harbours, demands a bow anchor laid well out and lines from each quarter, and a skipper who understands prop walk when going astern.
At night the stern shows a white sternlight covering the 135 degrees not covered by the sidelights. Seeing only a white light on another vessel usually means you are overtaking her, and an overtaking vessel keeps clear regardless of sail or power.
The stern on the racecourse
The Racing Rules define clear ahead and clear astern by the stern: one boat is clear astern of another when her hull and equipment in normal position are behind a line drawn abeam from the aftermost point of the other boat’s hull and equipment. Overlaps, mark-room and the entire leeward-mark rounding hinge on where sterns are. In starting sequences the stern of the committee boat is often the starboard end of the line, and ducking a starboard-tack boat means passing close under her stern with enough room that her boom does not sweep your crew.
Vocabulary
Aft means toward the stern; astern means behind the boat or moving backward, as in going astern under engine. Abaft means behind something on board, as in “abaft the mast”. The quarter is the region between beam and stern on each side. Sternway is movement backward through the water, and a boat by the stern is trimmed with the stern lower than designed.
Frequently Asked Questions about Stern
What is the difference between the stern and the transom?
The stern is the whole aft end of the boat. The transom is the specific flat surface that closes the hull at the stern. A double-ended boat has a stern but no transom.
Why do modern racing yachts have such wide sterns?
A wide stern adds stability when heeled and volume aft to support the boat when it is pressed downwind, allowing earlier planing and higher speeds off the wind. The design trades some light-air and upwind comfort for that downwind speed.
Which navigation light shows from the stern?
A white sternlight visible through 135 degrees, 67.5 degrees either side of dead astern. When you see only white, you are approaching from behind and are the overtaking vessel.
The stern is where the helm stands, where the seas catch up with you, and where the rules measure overlap. Understand what your boat’s stern is doing beneath you and you will steer better downwind, moor more calmly, and round marks with fewer surprises.