Sooty Tern No. 93
After a long hiatus since receiving the plans for my Sooty Tern from Stray Dog Boatworks (over two and a half years), I am finally setting up to start work on her. What was going to be a Tammie Norrie became, after discussions with Robert Ayliffe (SDB) and Iain Oughtred, an Oughtred double-ender, then crystallised finally into a Sooty Tern.
Not long after sending off for the plans, I searched the Wooden Boat Forum and found that Sooty Terns were almost as common as mice! I found threads by James McMullen, IanMilne, Max F, Vernon, EeBe4, Bassbug, and JCR1: invaluable resources for me, as well as happily confirming my decision on the Sooty. I also joined Off-Center Harbor for Geoff Kerr's 42-episode video series on building a Caledonia Yawl.
I am not sure that I can actually contribute much to the sum of knowledge about building a Sooty Tern, especially with the standard of the work done by those mentioned above. A blow-by-blow account probably isn’t going to be the best approach, especially since such things usually end up slowing me down significantly (I have already spent more than enough time on this first post already - this is the third draft and I still had to chop). So I may simply use this thread for occasional milestone-reporting and to ask the odd question.
Here’s a summary of what I intend to do with the construction, and where I am at at the moment:
The boat will be built in a sail-and-oar configuration, but not quite to the extent of Mr McMullen's. I have, however, taken careful note of his analyses in his ‘Everything Wrong with Rowan’ thread (see above) plus his replies to my PMs.
The building space will be a moderately-sized domestic garage. Early on, I made up a full-sized layout of centreline and station offsets on a (large) number of glued-together pieces of butcher's paper to check that the boat will: 1., fit comfortably in the garage while being built; and 2., be able to be easily extracted from it once it's finished.
I intended building the hull from three 9mm okoume plywood (lower) strakes and three 6 mm meranti (upper) strakes, but for stiffness decided to do the whole thing in 9 mm. Seven sheets (one extra for inevitable mistakes) of Bruynzeel 9 mm okoume 'Lloyds-certified' marine plywood were ordered from Denman Marine. I checked the sheets on delivery, and all looked fine - no visible voids on sheet edges, delaminations, etc. Both Bruynzeel and Denman Marine, after all, have very good reputations to protect. Some 6 mm meranti plywood may be used as well, e.g., for the centreboard case; decks and bulkheads (with cleats) will still be 9 mm. Stems and aprons will be laminated from Douglas fir, with keelson/keel/skeg also from Douglas fir, but not laminated.
The building frame will be made out of three lengths of 150 mm (6") x 42 mm (1-5/8") x 6 metre (19’ 8”) LVLs, since these are engineered straight and square. Two lengths will be used for the long sides; the third will be chopped up to make ladder-rungs and legs. These are yet to be acquired.
Moulds will be made from 12 mm (1/2") ‘CD’-grade structural plywood; three sheets of 3.6 mm (9/64") interior grade meranti plywood were bought for making plank patterns. Most other scantlings will be Douglas fir (Pseudotsuga menzesii - I have had extensive training in biological taxonomy and can’t help myself), with some other softwood and hardwood bits and pieces from my own exisiting stores. Some of the Douglas fir, and possibly some Sitka spruce (Picea sitchensis), will be bought from a local specialist timber merchant (Trend Timbers), who can guarantee clear and reasonably long lengths. Most of my own Douglas fir stocks will need to be mostly scarfed if used in lengths longer than about a metre (39").
I will be adding the Caledonia Yawl boomkin, anchored on the afterdeck (again, see Mr McMullen’s Rowan), and will make my own oars from Sitka spruce or Douglas fir - I have Mr Oughtred’s plans for these, too. There is a group of Australian trees known as ‘Silver Ash’ (several Flindersia species, which is why you can never really trust common plant names) whose wood I will investigate, too. The rig will be the standard Sooty Tern lug yawl rig (balance lug main, smaller sprit-boomed mizzen), mast and spars from Douglas fir and/or Sitka spruce; and the tiller will be the Norwegian type, per kind favour of Mr Oughtred.
Side-bench wood is yet to be decided on, and the height will probably be at that shown on the Arctic Tern Construction Plans I sheet for the open boat configuration, which shows them set level with the top of the upper centreboard case frame (and just at the lowest part of the internal lower sheerstrake curve), about 80 mm or 3 3/8” higher than the decked option (Construction Plan II). This will require an upwards extension of the bench supports, to maintain the 85-ish mm overlap with the floors (yet again, see the ‘Everything Wrong with Rowan’ link(s) above).
Epoxy will be WEST Systems'* 105/205-206-207, 401 Microfibre Blend powder for glueing, 407 and/or 410 fairing fillers and 423 graphite powder (possibly).
Following the design, permanent fasteners will be bronze, and embedded in epoxy. Pad-eyes may be installed for lifting purposes (again, see the Rowan repair thread). A shouldered galvanised eyebolt for towing will be set in the forward stem (see the later Geoff Kerr videos mentioned above). A fluid-filled globe compass may be installed in the face of one of the two buoyancy tank bulkheads. Also, a suitable bilge pump, port covers for the two decks (per recommendation from Mr McMullen), and 3M 5200 compound for bedding the centreboard case. Silicone sealant will be avoided like the Plague. I am also collecting pieces of lead for bilge ballast blocks and centreboard counterweight: I am not a particularly heavy person, and are my intended crew members aren’t either.
Current work:
Setting up to loft the Sooty Tern stem shapes, with quadruple-checking;
Going over the mould shapes and their relationship to the 9 mm-3/8" planking (the plans are drawn up for 6 mm-1/4");
Re-reading the plans, on which eight (ten) sheets there is a wealth of highly detailed information that has to be digested;
Chasing up prices of various items from suppliers;
Choosing an external house colour so that the painters can finish and I can get my workshop back!
I would very much like to thank the WBF Web Admin, who went went out of his or her way to fix a problem that was preventing me from logging into the Forum. Whoever you are, thank you very much indeed! And also for the almost total absence of 'likes' (except for 'rate this thread’) - what a relief!
Well, that will more than do me for the present, and be more than enough for anyone else too, I don't doubt. In fact, I rabbitted on so long that I hit the 10000 char limit and there wasn't room for snaps: maybe next time.
Cheers,
Alex.
* Up until mid-October 2022 I have so far only use the Australian low-irritant Bote-Cote resin, non-yellowing hardener and high-strength glueing powder, with no current intention to change. 19.10.22
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. Thank you very much for your own welcome. I will have a look for your Whilly Tern (congratulations again) and add it to my reading list.
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Originally Posted by PeterWidders
