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Rodondo's ketch
http://67.205.157.234/forums/viewtopic.php?f=27&t=5648		 Page 1 of 4
Author:  Rodondo [ October 8th, 2014, 4:18 pm ]
Post subject:  Rodondo's ketch
This is a hopeful candidate for a real design. Already working out finer details like fittings and the engine, this will be one of the most strongly built wooden vessels on the coast. I've chosen to work mainly with Spotted Gum and Victorian Ash for durabilty and strength. I think I can personally attest to the properties of Spotted gum, having been hit over the head with it, felt like iron :lol: Seems to be resistant to rot, is very smooth and hard, barely oily, just enough to prevent it from feeling dry.

Problem the boat's usual route,the Bass Strait & Westernport Bay, is minefield of obstacles if one deviates from safety. Hence the rigorous hull structure. The Victorian Ash ribs, between each to prevent a breech, two courses of Spotted gum planks (Laid in a running bond), the second to back the caravel laid planks, also to help brace the ribs apart. Behind that there will either be fire-retardant insulate or a foam with similar properties. This is to combat the fact the gaps between the courses of the Spotted gum will be filled with pitch and my own special felt to provide waterproofing and rot-proof layers. For added strength, the supports for the deck run abeam of the ship meeting at the waterline and just above the keel (Exceptions are present for ribs that run near the retractable keel). As the Victorian Berth for this proposed design is ringed with sharpest reefs I've ever seen in the Australasian region, the keel and underside of the hull will be sheathed in a course of 1/2" Australian Ironwood with a backing of 1/5" Buloke and a face of 1/4". This should also deter ship-worms and barnacles, I doubt many would like chewing into Buloke which should help anti-fouling measure should large portions of paint be removed. this also adds to ballast, which will also include concrete weights and iron bracing.

The keel I'm not exactly decided upon, Buloke in that shape and length is very hard to obtain so most likely spotted gum or Vic ash. A false keel runs the length of the keel, considering most of the keel is hidden by the planking and is flush with the surface mostly

I'm still deciding whether or not to have a retractable propeller and a square sail as well.

Still a WIP whilst I work on the rigging and hull shading

[ img ]
Author:  Thiel [ October 8th, 2014, 4:37 pm ]
Post subject:  Re: Rodondo's ketch
Well, I doubt she's going to be particularly fast but good luck with the project nonetheless.
I'd stay the hell away from retractable a propeller and go for an adjustable pitch propeller instead. They're less complex, faster to deploy, have basically no maintenance and structurally more sound.
What kind of topsail are you planning on using and are you using a hoisted or fixed gaff? The drawing seems to suggest both.
Author:  Rodondo [ October 8th, 2014, 4:54 pm ]
Post subject:  Re: Rodondo's ketch
Thiel wrote:
Well, I doubt she's going to be particularly fast...
How so?
Thiel wrote:
but good luck with the project nonetheless.
Thank you

I'd stay the hell away from retractable a propeller and go for an adjustable pitch propeller instead. They're less complex, faster to deploy, have basically no maintenance and structurally more sound.[/quote]

Ah, hadn't considered them, I've only had experience with retractable prop assembles

What kind of topsail are you planning on using[/quote]

I'm not quite sure yet really

and are you using a hoisted or fixed gaff? The drawing seems to suggest both.[/quote]

Its semi fixed, to be lowered if required but otherwise fastened in place to a collar on the mast
Author:  Thiel [ October 8th, 2014, 5:00 pm ]
Post subject:  Re: Rodondo's ketch
Because you're basically building an ice capable ship. All that planking and bracing is heavy.
Author:  eswube [ October 8th, 2014, 5:02 pm ]
Post subject:  Re: Rodondo's ketch
Very nice drawing so far. Good luck with making it real-life! :)
Author:  Rodondo [ October 8th, 2014, 5:03 pm ]
Post subject:  Re: Rodondo's ketch
Thiel wrote:
Because you're basically building an ice capable ship. All that planking and bracing is heavy.
Ah true that, small price to pay I suppose in order not to add the coast's long list of casulties
Author:  nighthunter [ October 8th, 2014, 11:28 pm ]
Post subject:  Re: Rodondo's ketch
Very beautiful lines!
Author:  Rusel [ October 9th, 2014, 2:16 am ]
Post subject:  Re: Rodondo's ketch
Up here we in NSW we'd use Swamp Mahogany and Turpentine for ocean durability. Further north Tallow wood is excellent.
Both 11-1200 kg/cuM. Ive some 200 yo Swampy boards from an original settlers hut and the grain is as straight as a die.
Turpy tends to be more twisty but I've split fence posts out of logs which worked well and Ive seen table tops with an excellent finish.
Spotted Gum IIRC can be very knotty, so you will need access to old trees to get straight planks that wont warp too much.
Looking forward to hearing how this goes. Are you sourcing directly from a mill or using an agent to find the timber?
Author:  Rodondo [ October 9th, 2014, 6:10 am ]
Post subject:  Re: Rodondo's ketch
nighthunter wrote:
Very beautiful lines!
eswube wrote:
Very nice drawing so far. Good luck with making it real-life! :)
Thank you guys!
Rusel wrote:
Up here we in NSW we'd use Swamp Mahogany and Turpentine for ocean durability. Further north Tallow wood is excellent.Both 11-1200 kg/cuM. Ive some 200 yo Swampy boards from an original settlers hut and the grain is as straight as a die.
Turpy tends to be more twisty but I've split fence posts out of logs which worked well and Ive seen table tops with an excellent finish.
I might consider Swampy Mahoghany if Spotted Gum is in short supply, my main issues being that its not as hard or as strong but it looks a good alternative
Rusel wrote:
Spotted Gum IIRC can be very knotty, so you will need access to old trees to get straight planks that wont warp too much.
Somewhat knotty from my experience (I've generally worked with older timber so that probably explains it), not enough really to be much trouble but enough to keep and eye on the timber when selecting
Rusel wrote:
Looking forward to hearing how this goes.
Thank-you :)
Rusel wrote:
Are you sourcing directly from a mill or using an agent to find the timber?
I, rather luckily am the son and grandson of two carpenters who run a carpentry factory who source all types of wood, our bench tops in our last home were made from the Kauri in the Cartlon Draught brewery, most gorgeous colour. So hopefully it should be rather easy obtaining it from their contacts, Buloke will be the hardest but 1-3 trees should provide enough timber and if I can't get it through the usual channel, I suppose I could just drive up the Wimmera with a trailer and ask around if any trees have fallen.
Author:  Rusel [ October 9th, 2014, 10:05 pm ]
Post subject:  Re: Rodondo's ketch
Ah, I thought you must've had some chippy in you!
Man, the stories your family could tell! I built pole and stone houses for a living back in the 80s. Felled the trees, portable milled them and then built the houses up in the hills. Such a privilege to be part of the whole process.
I dredged this quote from info on the Dent Shipyards in Jervis Bay.
"Timber used for wooden-hulled boats was Ironbark or Spotted Gum for keels and usually Beechwood for decking. Spotted Gum was used because of its bending qualities for planking. The timber was passed through a steam box and bent to the required shape, then secured into position. Blackbutt and Ironbark were used for stringers."
I've spent many hours bushwalking through the area and the Spotted Gum forests are glorious.
How big a steam box will you build?
According to Forest Trees - Dry Weight density for
Spotted Gum is 1080kg/m3: warps easily
Swamp Mahogany is 955kg/m3: very durable
Turpentine is 1005 kg/m3: high shrinkage, one of the worlds most fire resistant timbers
White Topped Box 1020 kg/m3: very durable (Ive found it very straight grain)
Grey Ironbark 1120 kg/m3: very durable, difficult to work, takes a high finnish
And down your way of course the king of them all -
Red(Mugga) Ironbark 1220 kg/m3: extremely durable, difficult to work, interlocked grain but a beautiful finish.
If I was closer I’d offer a couple days a month to help build your beast, what a magnificent project!
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