diff --git a/09_Battle/java/Sea.java b/09_Battle/java/Sea.java
index d9987f34..f0c31fac 100644
--- a/09_Battle/java/Sea.java
+++ b/09_Battle/java/Sea.java
@@ -1,8 +1,13 @@
+// Track the content of the sea 
 class Sea {
+    // the sea is a square grid of tiles. It is a one-dimensional array, and this
+    // class maps x and y coordinates to an array index
+    // Each tile is either empty (value of tiles at index is 0)
+    // or contains a ship (value of tiles at index is the ship number)
     private int tiles[];
-    private boolean hits[];
 
     private int size;
+
     public Sea(int make_size) {
         size = make_size;
         tiles = new int[size*size];
@@ -10,6 +15,8 @@ class Sea {
 
     public int size() { return size; }
 
+    // This writes out a representation of the sea, but in a funny order
+    // The idea is to give the player the job of working it out
     public String encodedDump() {
         StringBuilder out = new StringBuilder();
         for (int x = 0; x < size; ++x) {
@@ -22,13 +29,17 @@ class Sea {
 
     /* return true if x,y is in the sea and empty
      * return false if x,y is occupied or is out of range
+     * Doing this in one method makes placing ships much easier
      */
     public boolean isEmpty(int x, int y) {
         if ((x<0)||(x>=size)||(y<0)||(y>=size)) return false;
         return (get(x,y) == 0);
     }
 
-    /* return the ship number, or zero if no ship */
+    /* return the ship number, or zero if no ship.
+     * Unlike isEmpty(x,y), these other methods require that the
+     * coordinates passed be valid
+     */
     public int get(int x, int y) {
         return tiles[index(x,y)];
     }
@@ -37,15 +48,7 @@ class Sea {
         tiles[index(x, y)] = value;
     }
 
-    public int shipHit(int x, int y) {
-        if (hits[index(x,y)]) return get(x, y);
-        else return 0;
-    }
-
-    public void recordHit(int x, int y) {
-        hits[index(x, y)] = true;
-    }
-
+    // map the coordinates to the array index
     private int index(int x, int y) {
         if ((x < 0) || (x >= size))
             throw new ArrayIndexOutOfBoundsException("Program error: x cannot be " + x);