Complex sentence: A Thames sailing barge with no topsail-or top mast (stumpy-rigged) this enabled the barge to pass under London's bridges, get in close to shore for offloading goods and get far up river.
Split into simpler sentences: A Thames sailing barge with no topsail-or top mast sailing "stumpy-rigged". It enabled the barge to pass under London's bridges, get in close to shore for offloading goods and get far up river.