A monumental masterpiece depicting a 17th-century naval battle in silk and wool that is so fragile it has not been seen in public for 22 years is the subject of an urgent crowdfunding appeal to complete its delicate conservation. Royal Museums Greenwich needs to raise an extra £15,000 from the public in the next 28 days to save the tapestry, which was commissioned by Charles II and designed by the father and son team Willem van de Velde the Elder and Younger. The Burning of the Royal James at the Battle of Solebay, 28 May 1672, commemorates a naval battle fought off the Suffolk coast in the third Anglo-Dutch war. More than 160 ships and 55,000 men – including the Duke of York, who later became James II – took part. The tapestry depicts the Royal James engulfed in flames against a backdrop of delicately hued sea and sky, with tiny figures pitching themselves into the waves to escape the blazing ship. Cherubim battling with sea monsters decorate its borders, and a weavers’ mark has been woven into its galloon. But it has become structurally unstable due to age and its huge expanses of fragile silk weft, and the original vibrant colours have faded as a result of light damage. The first phase of conservation was completed last year when the tapestry was sent for cleaning in Belgium. It is now with specialist conservators in the UK with the aim of it being rehung at Royal Museums Greenwich next year. The tapestry has undergone about 350 hours of preparatory work to date, and conservators at Zenzie Tinker Conservation in Brighton have begun detailed repairs that will take until December. About £179,000 has been allocated to the project so far, but an additional £15,000 is needed for its final stages, including rehanging the tapestry in Greenwich. “This is a very complex tapestry to conserve,” said Zenzie Tinker. “It’s very finely and skilfully woven, with large expanses of silk. There is extraordinary colour, billowing clouds, cresting waves. If it was conserved badly, you’d lose all that detail.” Measuring almost 4 metres by 6 metres, it is the largest tapestry Tinker’s team has worked on. They have divided it into 20cm wide sections, each of which will take an average of 100 hours of painstaking and backbreaking work. The team has dyed wool in more than 60 shades to match the original tapestry, and is using a combination of fine cotton and polyester to replace silk that has degenerated. “We need this to last indefinitely. Silk is too shiny, and degrades too quickly,” said Tinker. Some earlier repairs, dating from the 18th and 19th centuries, need to be unpicked and rewoven. But almost all the original weaving will be preserved and reinforced. Hazel Arnott, the lead conservator on the tapestry, said the work was intensive, requiring regular breaks to avoid eye strain and muscular pain. Although there was a lot of consultation and planning among the three conservators working on the tapestry, she also liked to listen to audio books – currently Anthony Trollope – while stitching. The £15,000 appeal is being made through Art Happens with Art Fund, a crowdfunding platform for museums and galleries which sets a one-month deadline to raise money.