Eruvin 42: Blurring Eruv Techumin with Eruv Chatzerot

THIS IS SUNDAY'S DAF. Eruv techumin vs. Eruv chatzerot - note that they're really different (which means that there's no carrying for the distance of eruv techumin). What if you don't know exactly how far the 2,000 amot of the techum takes you? What if your extended techum runs into a non-Jewish private domain? What if you need an eruv chatzerot to be able to carry where you're going? Plus: Another discussion of the partitions on a ship. If the walls are broken... But how does a boat function? ie does the movement of the boat through the water change how your own movement through the space is assessed?