Restor­ing tra­di­tional Whitby lifeboats

How boat­builder and lifeboat­man Mike Coates en­sured the sur­vival of two clas­sic Whitby lifeboats

Practical Boat Owner - - Contents - Mary Ann Hep­worth,

Mike Coates on the ar­ray of tech­niques needed to re­pair dou­ble-di­ag­o­nal con­struc­tion

In the late 1960s I joined the RNLI as crew on the in­shore lifeboat and of­ten made up the crew on board the a 41ft Wat­son Class ves­sel. She was a non­right­ing twin-en­gine motor lifeboat built in 1937 by Groves and Gut­teridge on the Isle of White and was at the time state of the art in lifeboats.

Thirty years later she was in poor shape and needed some fairly se­ri­ous re­pair work, but her dou­ble-di­ag­o­nal con­struc­tion was a ma­jor hur­dle and was threat­en­ing to be the death knell for this clas­sic ves­sel.

My first foray into re­pair­ing dou­ble di­ag­o­nal was from the same pe­riod in the late 1960s, re­pair­ing Fire­fly dinghies that were mass-pro­duced us­ing hot moulded dou­ble di­ag­o­nal. The hulls were con­structed us­ing flex­i­ble 3mm thick wooden ve­neers laid di­ag­o­nally over a fully bat­tened build­ing form and tem­po­rar­ily sta­pled in po­si­tion. A sec­ond (and some­times third layer) was then laid at ap­prox­i­mately 90° to the first with a layer of glue be­tween each. Usu­ally the plank­ing would start ap­prox­i­mately mid­ships with strips of ve­neer be­ing butted each side of the ini­tial strip. Once the lay­ers were fin­ished, the whole thing was cov­ered over and fed into an au­to­clave to cook, cre­at­ing a hard, light, durable shell.

A cry for help

The Mary Ann Hep­worth en­tered ser­vice at Whitby on 11 April 1938 and re­mained on ser­vice at the sta­tion un­til 1974 hav­ing served for 36 years, launch­ing 372 times and be­ing cred­ited with sav­ing 201 lives.

Af­ter her decom­mis­sion­ing in 1974, she was sold by the RNLI and con­verted to a motor cruiser on the Broads and the River

Trent. Later bought by lo­cal lifeboat crewmem­ber Barry Sned­don, she was re­stored as an open lifeboat and put into ser­vice as a pas­sen­ger ves­sel at Whitby.

In 1999 I was sad­dened to hear she’d been dam­aged; ru­mours quickly spread she was be­yond eco­nom­i­cal re­pair. Barry asked if there was any way I could help as he’d heard I pre­vi­ously re­paired dou­ble di­ag­o­nal hulls.

I ex­plained my ex­pe­ri­ence had been lim­ited to glued dou­ble di­ag­o­nal hulls and that the Mary Ann was built with nailed dou­ble di­ag­o­nal plank­ing, but I was his last hope of find­ing some­one to re­pair her lo­cally. Hav­ing ex­am­ined the dam­age, I be­lieved I could carry out a sat­is­fac­tory re­pair us­ing lay­ers of ve­neer. But there were plenty of hur­dles still to come.

Ini­tial re­pair dif­fi­cul­ties

Un­like the dou­ble-glued ve­neer con­struc­tion of the Fire­fly, the Mary Ann was built with an in­ner plank of 8mm Brazil­ian ma­hogany, a layer of cal­ico cot­ton soaked in white lead/lin­seed oil mix­ture and an outer 9mm ma­hogany plank­ing. The two lay­ers were then fas­tened with three rows of cop­per nails and roves at ap­prox. 50mm (2in) in­ter­vals. The cal­ico and white lead mix pro­vided a flex­i­ble wa­ter­proof mem­brane be­tween the two lay­ers of plank­ing.

How­ever, as a pas­sen­ger­car­ry­ing ves­sel, any work on the Mary Ann had to be over­seen by the Mar­itime and Coast­guard Agency (MCA). They in­sisted on full-length plank re­pairs from gun­wale to keel not only mak­ing the re­pair com­pli­cated, but also pro­hib­i­tively ex­pen­sive. I asked for an on-site meet­ing with the sur­veyor, who re­it­er­ated his re­pair rec­om­men­da­tions. His view was that it wouldn’t be pos­si­ble to bend (even steam bend) short lengths of plank­ing into place with­out caus­ing stress­ing at the end of each plank and that this stress­ing cre­ated the pos­si­bil­ity the joint wouldn’t lie flat or may even open up in use.

Ad­di­tion­ally the sur­veyor in­sisted that I use a tra­di­tional non-set­ting oil-based mas­tic be­tween the planks – which im­me­di­ately put glu­ing out of the ques­tion.

Dur­ing our some­what frus­trat­ing meet­ing I ex­plained my plan of at­tack: I was hop­ing to use mul­ti­ple lay­ers of ve­neer to make up each plank thick­ness – 3x3mm for the outer plank and 2x3mm and a sin­gle 2mm for the in­ner – with each layer glued with epoxy. In my opin­ion this would al­low the con­tour of the orig­i­nal plank­ing to be formed with very lit­tle stress within the new plank.

While he ac­cepted the virtues of lam­i­nat­ing each plank he wasn’t happy about me us­ing epoxy, sug­gest­ing it would cre­ate a hard spot on the hull and would cause a prob­lem where the re­pair joined the orig­i­nal hull struc­ture. How­ever, he did even­tu­ally con­cede that a flex­i­ble ad­he­sive might work.

My thoughts im­me­di­ately went to Sikaflex, but on see­ing a tube of black Sikaflex 221 he re­jected the idea on the grounds that a polyurethane sealant wasn’t a suit­able ad­he­sive. So I was left to sub­mit a num­ber of glued ve­neer sam­ples for de­struc­tion test­ing; these were made up us­ing Sikaflex with the ad­di­tion of Sika Mul­ti­pur­pose primer, but this time I used white! The sam­ples were sup­plied with planed edges show­ing the white line of the Sikaflex with­out any ref­er­ence as to what had been used. A few days later I got their re­sponse... ‘Ex­cel­lent! On each sam­ple tested the tim­ber failed be­fore the ad­he­sive. You may com­mence the re­pair work’. They did how­ever make a pro­viso on min­i­mum plank lengths in­sist­ing on a stepped lapped joint rather than the scarf joints I’d pro­posed. All work would have to be signed off at each stage.

The only prob­lem I could fore­see was to en­sure any signs of Sikaflex were kept well out of sight!

‘Mary Ann was built with an in­ner plank of 8mm Brazil­ian ma­hogany’

Mary Ann Hep­worth leav­ing Whitby har­bour when she was in ser­vice

Di­a­gram show­ing how Mary Ann Hep­worth’s dou­ble plank­ing was put to­gether

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