The Initial Design Process:

Date Discussion
It's hard to know where the process of building a boat starts. Does it start with the dream, the purchase of the plans, the payment of the first real money for material, or the laying of the first piece of timber?

Perhaps it starts even further back. As a child, which is a long time ago now, I usually spent my annual holidays with my parents and their friends on a boat somewhere and my father, a keen angler, loved the water and rivers in particular. As with many of us, it is not until retirement that one has the time and resources (stock market notwithstanding) to relive the pleasures of that time.

I am lucky enough to live in close proximity to the largest river system in Australia, which when not in drought as it is at present, can have up to 6,500 Km of navigable water available to explore.

What follows is a log of the development, construction and hopefully completion of a vessel still called "River Belle at present for reasons that will become clear.

2004 Undertake tertiary education in wooden boatbuilding.
2005 Undertake tertiary education in wooden boatbuilding.
2006 Undertake tertiary education in wooden boatbuilding.

2007 I have undertaken significant research during the year looking at plans for shallow draft river boats. In that time, I discovered William Atkin (1882-1962) and his "Tunnel Stern" designs dating from 1922, which seem like a great idea. The propeller is set partly above the water line in a tunnel, which allows a vessel drawing only 380mm to use a 457mm propeller, which is a very neat trick! The bottom is flat and is below the line of the propeller and rudder protecting both areas from damage if the hull does touch the bottom, which is ideal in a shallow river environment.

I also have a major interest in solar power, given that my background is electronics engineering, so silent cruising via free power from the sun is also a very attractive proposition. As a proof of concept, I have been inspired by a vessel built locally by Duck Flat Boats called Nomad III, which is a 30' solar powered river boat. A full description of Nomad III was published in the "Australian Amateur Boat Builder" in March 2005.

A solar electric vessel is a relatively simple proposition these days because all the necessary components are already available for the dedicated greenies who want to live "off grid" and generate their own power. A 36v system was selected because it suits the MARS brushless DC motor. This particular motor is made by Briggs & Stratton and has no moving parts aside from the armature. Electronic controllers are readily available from various suppliers.

24/12/2007 I have finally settled on one of William Atkin's designs called "River Belle". It was first published in "MoToR BoatinG" magazine in 1943 and again in book form in 1944 called the "Ideal Series, Volume 20", with the title "Forty Designs for Postwar Boats".

The "River Belle" design is an evolution of the "Tunnel Stern" concept originated and developed by Atkin for efficient and high speed travel in very shallow water. His first design using this approach was published in 1921 called "Mischief", which was then significantly refined over the years.

Happily, many of the plans developed by William and later his son John, both now passed away, are still available through William's daughter-in-law, Ms Pat Atkin, a charming lady who can be contacted via her web site:

Jan 2008 I have received the plans and lofted the Offsets Table to 1/10 scale and used the trusty computer to convert to metric on the way by. Have purchased Balsa wood to make a model to practise building the hull on a small scale and to help determine internal layout.

Jan 2008 After a long and agonising deliberation - I have decided not to use solar power. There are two reasons, the first is cost and the second is performance.

When pricing up the "Bill of Materials it turns out that the cost of the solar solution, over some of the alternatives, would almost double the expected cost of the boat, which is beyond my budget.

The maximum power available from the area of solar panels and number of batteries that could be carried, would limit the available power to around 5hp for four hours per day. This is OK for very, very leisurely cruising, but a long way short of the 80hp specified for the design to provide decent performance.

So much for silent cruising for free!

Feb 2008 Bought two books on wooden boat building. One is "Boat Building With Plywood" Glen L Witt. The other is "BoatbuildingĀ by Howard I Chappelle - the Bible"

I have also since purchased "Devlin's Boat Building" by Samual Devlin. It is subtitled "How to build any boat the Stich-and-Glue way" and is an excellent book which I thoroughly recommend. It is one of those rare books that you can sit down and read from cover to cover and enjoy as a light hearted journey through the boat building process, and also keep handy on the bookshelf as a detailed technical and "How-To" reference. It is especially useful if you are looking at building a boat that was designed for sawn frames and solid planking from plywood and epoxy.

27/2/2008 Quite by chance, saw an advertisement for a 1965, GM, six cylinder, 149 cu in petrol engine (Holden EH) fitted with a Borg Warner Velvet Drive 72C gearbox and reduction gear.

It has come out of a local river boat called "Tradean" and is fully marinised, mounted on a steel frame and is ready to go. It may be heavy on petrol, but it is so much cheaper than the solar solution - who cares?

28/2/2008 Spoke with Alan Marsh (otherwise and more generally known as "Moose") the shipwright, to confirm use of Workshop at Port Elliot starting in April.

Moose recommended that the "Stitch & Glue" method was the way to go. Much easier, cheaper & lighter. Certainly quicker than making all the frames in the plans.

4/3/2008 Design of interior layout started. I only want a Queen size island bed, with comfortable facilities for two people. I don't want any other accommodation. Freeloaders - bring a tent! The design goal for the interior is to be able to "Sleep 2 people, Feed 6 people and carouse with a crowd.

19/3/2008 Met Karyn & Roger Baker on "Pobblebonk at Mannum. After much discussion over a cup of tea, they provided a picture of a river boat called "Megan", which became the inspiration for the exterior style and more particularly the window shapes. It also provided the idea of the raised stern castle which is to be the Stateroom. The "Megan" set the target era, or "look", for the boat, which was a big step forward because until then I had no clear idea of what I was trying to create and was really stuck.

After a casual conversation about propellers, Roger was able to provide an 18x15 ex Halvorsen propeller which should be just about perfect. Calculation suggests that the target cruising speed of 10Kph should be achieved at about 1450rpm (27% slip).

Atkin's design specifies an 18x9 driven with an 80hp engine to achieve 24 Kph. This particular Velvet Drive gearbox has a 2.59:1 reduction gear fitted which, through Dave Gurr's excellent book "The Propeller Handbook suggests that an 18x13 would have been better. However, speed has never been a design goal, and I seriously doubt that a forty year old car engine is still going to produce anything like its original rated hp.

So, to be able to cruise efficiently at or just below "hull speed of (about 15 Kph), is all that's required and an 18x15 should be just fine.

22/3/2008 At dinner one evening, after crewing on the historic paddle steamer "Marion" (1897) for the day, drinking "River Red" from Rockford Wines suggested the name for the boat as "River Red". Next day I arrived at the idea of "Shiraz" as simply representing one of my favourite pleasures in life so why not use it as a name to identify another? This decision also decided the eventual colour for the boat as heritage red and cream with detail dark timber window mouldings.

Actually, the working name at the moment is the "Happy Squanderer", which I think is a fair description of any boat - as they all squander time and money in huge quantities.

April 2008 Workshop not ready. Have spent much time playing with the boat's internal layout. I thought it would be relatively simple after finalising the hull design, but not so. The shallow draft means that to achieve usable headroom, the cabin roof has to be around 1.8m above the water line and starts to make the overall profile look odd.

On Moose's suggestion, I have raised the bow to 1.35m above the LWL, and added a drop in the sheer back to the original level between stations 5 & 6. I have moved the stateroom, with island queen size bed, to the bow and added a small raised coach house to give the necessary headroom.

I wanted to have Club Lounge style seating in the stern with roll down clear plastic blinds. This made the engine position a real nuisance so I have moved it forward, which has allowed the prop shaft to sit level. This is the only change to the below water line section of Atkin's original hull design so far.

With the engine further forward, I now have a raised Helm Deck with the engine underneath. This allows a view forward through a three part windscreen over the roof of the forward cabin roof for the helm position and the raised deck allows much more space to hide tankage etc.

I have spent a lot of time on the sizing and layout of the shower/toilet. After a visit to the Camping and Caravan Exhibition, the final design was taken from a popular mobile home.

There is some ongoing discussion about changing the sheer again to ensure the "prettiness" of the final design, but otherwise I think the design is more or less set.

The first material required for the building process is some sheets of chipboard for Station moulds. Someone suggested that a recycling outlet might be considerably cheaper than buying new. Even better, we subsequently found a furniture factory that has chipboard cover sheets on its imported products that it is happy to give away. Therefore, I was able to get 25 sheets of 3.6m x 1.8m x 12&16mm, which is enough for all the station moulds for free, even if I did have to hire a tandem vehicle trailer for $65 to pick them up.

I have also been working on the engine. I decided to remove the welch plugs just to see the state of the cooling water jacket and I was absolutely astonished at the volume of mud and silt that was inside. It took over an hour with a hooked piece of wire and a hose to get water through the jacket to run clear. If the block was so full of crud, it seemed prudent to remove the cover plates on the front of the block and the cylinder head as well. Same story. In addition, the aluminium fitting from Tawco used to adapt the cooling system to marine use was almost eaten through and was completely blocked with aluminium oxide. I made a new one in steel. The plate over the old water pump location was removed, refaced and with a new gasket, was refitted. The impellor in the Jabsco coolant pump was damaged and a new one has been ordered. The mechanical fuel pump has been removed and a cover plate and gasket made to fill the hole. (An electric pump adjacent to the fuel tank will be used as a safer alternative arrangement).

An electronic ignition unit has been sourced, but is yet to be fitted. Once that is done, the engine should run, although it will need a new air cleaner/silencer at some stage.

19/5/2008 Visited the Workshop today for the first time. The clearing out still isn't finished, but it needs other things too. First is some decent lighting.

It is 84Km from home and takes an hour to get there, so staying overnight and working two or more days at a time seems a good idea, but there is no toilet on site which is a problem.

Started the 1/10 scale half profile model last week and added stations 10, 11 & 12 today. All made from 3mm MDF seems to be working well.

11/6/08 Last week Moose suggested building the sides of the hull, above the Chine, using Lapstrake/Clinker method with plywood planks instead of flat plywood sheets.

This approach would make construction easier in the sense that I have had previous experience with it and it also would make a stronger hull because of the reinforcing provided by the rows of double layer Lapstrake joints.

It also seemed reasonable that if I am going to use Lapstrake construction, then it would be just as easy to make the hull profile curved above the Chine instead of flat which would make the boat much prettier. A side benefit (no pun intended), and in reality the clincher for me, is that it would also make the hull above the water line, a bit wider. It turned out that the breadth changed from 2.75m to 3.12, and interior space is never enough, so this is a worthwhile improvement.

So, back to the drafting table to change the hull sections to have curved sides instead of flat not so easy, as I discovered. I couldn't work out the maths or geometry attached to this type of design from the few samples I could find on the Internet so after much research in books and looking at other plans, it was all done by "eye" and a French Curve ruler. I have started yet another 1/10th scale model in MDF (the third) now with curved sides and have just put the first part of the bottom on. It will be interesting to see if I can successfully "plank" my curved model profile stations. I am using 0.6mm kitchen laminate for the model's hull because it curves much like plywood. If the laminate sits on my station profile designs, then the full size plywood planks should too.

It has been six months since I got the plans for River Belle, from Pat Atkin, and the decision to alter, not only the interior layout, but now the above water hull profile as well, has turned out to be a major undertaking taking many, many hours of researching and head scratching as well. If I were doing it again I would not embark on changing plans lightly. Having said that, I am really pleased with the result, and can't wait to start building. I'm sick of the design and re-design process now, let's move on.

10/7/08 The latest half-breadth model, with clinker built curved sides is almost complete. The kitchen laminate I was using proved to be too hard to glue, so I changed to modeller's plywood. It is three ply Birch, to marine specification, and is only 0.6mm thick; great stuff to work with, albeit expensive. I paid $27.50 for a 4' by 1' (1220 x 300mm) sheet.

The bottom of the model is finished and the first four planks are on. The lines look really good although the bow doesn't sit properly on the stem post yet. There may be little point in going further with the model because it is clear that the design will work.

I showed the lofted plans, new Offsets Table and model to Moose today and he was very pleased with how it had come out. The next step is to develop a materials list and start pricing plywood. Moose has suggested Hoop Pine to AS2272 as the only way to go. It is expensive and dense (heavy), but it is the strongest plywood. I am not proposing to Bright finish (Clear Finish) the hull, so I am not so concerned that Hoop Pine grain is so regular it's boring.

Went to the workshop again today. The remainder of the new light fittings are in and wired at least now I can see what I am doing. I have extended the strongback that was already in the shed from 8m to 10.25m which in a 12m shed makes you realise how big this thing is!! Also today, I have welded the brackets to the strong back to hold the Station Moulds. It seems that I am now committed to building this thing.

Which is good, I think.