The 'Trading Wherry' developed from the Keel. It is double-ended, its hull painted black with a white nose to aid visibility after dusk. Most trading wherries were clinker-built, but "Albion", surviving today, was the sole example to be carvel-built. They carry a gaff rig, the sail historically also black from being treated with a mixture of tar and fish oil to protect it from the elements. The mast tops and wind vanes were often painted or shaped (respectively) to identify the wherry's owner - a traditional design is a 'Jenny Morgan', after a folk song character. Sizes varied, but many of these vessels would carry around 25 tons of goods. Wherries were able to reach larger boats just off the coast at Great Yarmouth or Lowestoft and take their cargoes off to be transported inland through the broads and rivers. The last trading wherry, "Ella", was built in 1912.