Back to the Boat - Cabin Fever

At last some free time to potter in the boatshed! Taking stock of where I last got to (it's been a while) I've been making some modification to Kees Prins "Far Fetch" plans.  The main mods done to date are lengthening the hull by 8 inches to 17 ft 5 inches, centering the outboard cut out and adding twin rudders. The remaining item I had not yet modeled was the cabin size and ergonomics. To do this I first built a "lining-off" jig out of quad aluminium tubing and plastic connectors. This sits on my workbench over the model and I can measure down from the centre bar into the hull to check all mods and also do final lining off of the whole model prior to modifying the original plans from Kees Prins and Iain Oughtred.  You will see a pic below showing me starting to use this with the work I am doing on cabin design.

First thing I did re cabin space was to add 2 inches to the sheer. You can see this in pic above - pretty rough planking with that gap there but I will fair it up later. This was a bit of a pain to do as I had already fitted an inwale on the previous sheer plank. Next I added deck beams at station 2, 3 and 6 (the main structural deck points where I would be playing with cabin shape) and then made a cardboard deck. I drew a preferred deck perimeter for the hull/deck joint and made (extended) focal point of these curves ending just in from the bow where the forestay is to be anchored (you will see this point used in later pic re cabin slope). I took lining off x,y,z's of these perimeters and played with them on Delft ship CAD to get fair lines then.  After many cups of tea and coffee sitting looking at various ideas I came up with the following cabin profile which gave me head space sitting up in the bunk and included an extended front cabin roof for a bit more airspace and dry storage (there will just be a deck beam there in the middle, not a bulkhead as in the mock up).

Now to make a more permanent cabin model which I have started in the next pic. I am making the whole cabin structure above deck as a separate item so I can lift it off and view internal space as more detailed internals are checked.

Here's an amended draft on Kees Prins plans to show the full extent of hull and sheer increase and the new cabin design (new profile lines in red). New cabin is (relative to waterline) 9 inches higher at rear, 3 inches higher at front (both include the extra 2 inches sheer) for main cabin section and the forward extension is 17 inches long.  Note that there will now be no anchor hatch - this will help maintain clear foredeck space given the extended cabin. I intend to keep the anchor and warp in a self contained box inside the hull.  I also have plans for a small dorade box in the front cabin section to improve hull airing in our hot humid climes here.

I suspect waterline will come up a bit with the added displacement from higher sheer and cabin profile and it is starting to look a bit more like a motor sailor but that's acceptable compromise for me.

Here's some more pics a few days later after adding some more realistic cabin facings. Umbrella pole is roughly where mast will be.

A view dead ahead from about waterline level....

...and side on at deck level with 15 degrees heel....on the wind.

Sidetracks - New England in the Fall

We are not great world travelers but a long held ambition was to see New England in the fall. So we booked up this trip 12 months ago and so spent a glorious 8 days touring through Mass, Maine, New Hampshire and Vermont. I would like to have taken some sidetracks in Maine to Wooden Boat base and Eggomoggin Reach but our bus route wasn't close enough to do this. But we did spend two days on Mount Desert Island and I got my fill boating venues there.  With some guidance from Kees Prins (who had tracked around here shortly before our trip) we got to see some beautiful little harbours around the island.  We also used our free afternoon in Bar Harbour to do a scenic flight around the island and pass over 7 of the cute Maine coast light houses.  Here's an aerial shot of Somes Sound (John Brooks named his version of Herreshoff 12 1/2 after this).  It's the only fiord in the USA.

We happened to be there when the federal government shutdown was on so access to National Park was closed - see below at Arcadia National Park on Mount Desert Island this was a close as we could get to Cadilac Mountain.

Autumn leaves were near their peak throughout New England an here's a couple of glimpses.

Mt Washington

New Hampshire Lake at Rocky Gorge

Lexington Green near Boston

Saw the following model of Herreshoff J boat Reliance at MIT Marine engineering display in Boston

Sidetracks - Big Boat Cruising

Not much activity on the boat building front due to another semester of teaching underway and some family holidays. This first holiday was "Big Boat Cruising" to Vanuatu and New Caledonia. First time for my wife and I and reason was to accompany our live wire 93 year old Aunt on a food and lifestyle experience away from the boredom of retirement home. Here's a pic of our floating home in Vanuatu harbour - a very appealing harbour with sheltered coves (apart from cyclone season I guess!) and very pleasant locals.

 Under way, I found the balcony of our cabin the place to be - listening to the waves slip past the hull and the wind past the ears - mainly from the 15 knots of engine speed.  Too far from the water up on deck 11 for me - I'd much rather be on the deck of this ketch we saw slipping out of Noumea for an afternoon sail.  I'd saved up a book to read on the cruise which was equally nautical and absorbing - "The Great Race" by David Hill about the mapping of the coast of Australia by Mathew Flinders and simultaneous activities of French explorers to do likewise. 

 

Model - Twin Rudders Version 2

Here's my second attempt at the twin rudder system. It's more compact and everything will fit within a decked narrow  intermediate section between the end of cockpit bulkhead and another bulkhead in front of the outboard well area.  Stern area is now very clean with just the push rods attached to the rudders and these have little lateral movement so will be scope for a couple of narrow hatches on the sides and plenty of buoyancy to be built in. I tried my hand at a video to demo the twin rudder system.

Model - Steering Systems and Twin Rudders

I'm now getting into uncharted waters - design variations not drawn by Iain Oughtred or Kees Prins - I will be getting back to them on this before the build. I wanted twin rudders so I can centrally locate the outboard and so steering on the wind and in rough water will give more efficient rudder control.  I also want to see if I can rig a removable stick rudder control in the cockpit as an option to a tiller (I will still have a tiller but linked to the same system controls).    Here's a few pics of a construction model I have set up specifically to test this out (and also test the cockpit people space).  Note my shop made mannequins of 1/5th size me and crew (note: crew has not committed to joining this ship yet).

Below is pic of transom with outboard cutout and sticks representing rudders (at 12 degree incline to vertical) and end of cockpit bulkhead. The rods at the top lead into the edge of the cockpit seat where the stick control attaches. The lever system here uses hobby shop ball joints - real boat would have stainless steel rodends and rod and system would be more compact than here. Rods will not project through the transom as shown here.

 

Here's the skipper and crew seated in the cockpit and the stick control in the skipper's left hand attached to the rod which feeds through the edge of the cockpit seat to behind the bulkhead. There's a fairly small arc of movement of the stick control (+/- 30 degrees) which transfers to +/- 45% at the stern where it meets the rudder cranks.  Leverage is provided by length of stick and rudder crank for about 4 to 1 ratio of effort. Above you will see a bar that ties the the two rudder controls together, low down just behind the bulkhead.

 

I'm not convinced this lever system is viable. Whilst it all works fine in model, the lever angles are not optimum and the system is cluttering up stern space for buoyancy and storage.  I am now starting work on a drum and rope system which will be more compact - but still including cockpit joystick and optional tiller (each removable). It will work off rudder cranks higher up on the transom and with less crank cutout in the transom. The outboard cutout will be reduced because I am now convinced I need long shaft rather than short shaft.  Current motor thinking is Tohatsu 4 stroke 6HP with external tank.

I'm happy with the cockpit space and the extra 5 inches I have added here by extending the stern.  The space between cockpit and transom will be taken up a short decked area with mainsheet traveler and removable gallows space and them followed by drainage well under the motor cutout and space for 12 litre fuel tank, fenders and wet weather gear storage - lots of buoyancy will be built it below this and along hull around this.

 

Model - Turnover celebrations

Well finally I got the planking finished and comes a time when we hold our breath and wonder if the hull will actually come off the jig. I had waxed the ribbands with parafin wax but still wasn't confident of an easy release because I wasn't able to get under the hull during planking to clean up epoxy (I will be able to do so on full scale build). Anyway a few squeezes and tap on planking and eventually she popped off with no damage. The building books say allow yourself a small celebration at turnover stage so I did just that (see below).

You will see in the top right I have managed to save the building jig without any damage so another model like this could be done by me or anyone else interested in the exercise.

Here's a closer view of the hull. There's a few rough spots and short cuts but I am pretty happy with the outcome given the purpose. I didn't cut conventional gains on planks at the bow (because the ply was too thin and brittle to cope with the chiseling) - instead I cut a full thickness rebate in the overlapped plank to give the same effect - I'll fill the air gap with some filleting.  I'm going to try for cutting gains at the stern on the full scale boat - it will be much prettier and avoid having to cut rebates in the transom.

Model - Planking Lessons

As mentioned earlier in this blog, one of my objectives in building a model of Skye Maid before the real boat is to put myself through a DIY boat building school (learn from mistakes cheaply) and get the logical order of doing things sorted in my mind. Despite reading lots of books, I forgot that I needed to allow for the thickness of overlapped plank edge when making patterns - that is until I got to the fifth plank as we round the bilge and plank shapes become their weirdest.  So from there on I moved straight to John How's method of making the plank patterns using two battens stuck together with criss cross sticks stuck with hot stick gun. Ian Oughtred also covers this approach on page 59 of his book but using screws instead of hotstick glue. Some pics and comments follow on my journey so far fitting planks to the model. You can easily ply apart these patterns after copying the plank shape and reuse the battens.

  

 In the above pic you can see the two battens, one clamped to the bottom edge of the last plank glued on, the other is clamped over the top of the next ribband below - this gives top and bottom edge of the next plank to be added. The cross sticks are then stuck on, to preserve the pattern allowing for the exact bent curvature of the plank.  Once unclamped, this pattern can be traced onto planking stock. Remember to mark key locating positions on the pattern (midship mould, bow, transom) before unclamping it and these marks need to be traced onto the planking stock as well as tracing plank edges.

The above pic shows the U shaped clamps I made to hold planks on (an Oughtred idea). The wedges I found at Bunnings for about $10 a box - in a range of different sizes - the wedge gap (plank to clamp) varies from top to bottom of plank because of extra thickness at the laps.

This pic is rather overexposed but it's starting to look like a hull with dry fit of the fifth plank added.