Building a TUG

[Barbaros]

Hello,

This is my first visit into this forum which I found very usefull and very helpfull.
There is a lot of people w/experience exchanging ideas and knowledge.
Simply, this is amazing.
It will require some weeks to read most of the messages.
(Sorry, my English is quite poor and I am working with a dictionnary next to me).
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Shortly here is the story.
I am planning to build a vessel, as you can see, inspired from "TUGs".
The dimensions are 11m65 X 4m X 0,80m (approx 38.5feet X 13.21 X 2.64).
There will be one (or two) cabines in the front and one in the aft.
The wheelhouse is in the middle and the engine room (quite wide) is just below.
The decision of building either in "Steel" or in "Plywood-Epoxy" is not made yet.
This choice will -obviously- impact the plans.
Engine power, propeller diameter and pitch are calculated according "Dave GERR's", "Propeller Handbook".
The navigation area could be anywhere around the world (except crossing Oceans).
Visiting a huge majority of European inland waterways are in the plans also.
Wheather type : would like to avoid gale conditions.

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My first question, to all of you, is it a mad (or insane) project.
Your comments are welcome and strong help will be needed during planification phase.


Kind regards.
Eric.

8681

8682

p.s. As reference, I am using "Dave GERR"s, "Boat Strength".

[Richard Hillsid]

Nice , just remember some European inland waterway tunnels are pretty low head room, and have speed limits so figure out a engine that is economical at the posted speeds.

[Crag Cay]

I think your plans look excellent.

The canals are very rough going. You tend to hit more things than you do as an ocean sailor. Steel will be tougher, especially when the canals freeze.

But you will have to build it in a material you like working with. Steel and plywood have very different 'feel' to them. If you like the idea of wood, then you should also consider aluminium as wood workers often prefer building in this rather than steel.

Remember your maximum 'airdraft' needs to be less than 3.5m.

If you can arrange for the wheelhouse to dismantle down to 2.5 metres you can include the Midi and Brittany canals in your cruising plans.

Don't give up too much room to the engine. Everyone likes the idea of a proper engine 'room', but afer you have cruised for a while, using more space for 'living' seems a better idea.

[SeaSpark]

Hoi Eric,

Your plans look great!

I agree with everything said above and would like to add:

Modern engines are small and need less maintanance than before. You do not need an engine room. Build the engine in a soundproof box in the interior. Make the box removable so you can work on the engine.

Aluminum is hard to weld. Glass/ply/epoxy structures can be build very strong. Steel is a very good option for the amateur builder but not everybody likes to work with it (same for epoxy and glass). Steel will be cheaper to build but use more fuel.

The isocurves in your rhino image distort the lines of your plans. A side and top view without isocurves + perspective rendered images will help to understand the design better.

Your design looks a bit high make sure to check stability.

Fold down steering houses are very common for canal boats.
If you plan to cross seas like the med and north sea a fold down steering house should be "sacrificial" when it is swept away by big seas the boat should still be save.

Bad weather is not always avoidable.

Best of luck with your design,

Jeroen

[Barbaros]

Hello Richard, Crag and Jeroen,
(... and others who may read these lines ...)

I appreciate your answers.
European waterways is a matter of compromise in terms of dimensions.
I will keep only major "routes" like "Europe from north to south".
Canal du midi is another story (because of one single quite low bridge located half way in the middle)
Since, this chef-d'oeuvre was built around 15th or 16th century ... don't even think about it.
I am affraid, the removable wheelhouse is quite risky with rough weather on the sea.
So, the choice is oriented to the sea "first" and inland waterways as "secondary" choice.
As long as I can reach far below south of Paris It's OK.
But I agree with you, the full canal option is quite different then full sea version.

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Now regarding more detailed plans, such as curves and fairing the hull lines ...
I was thinking to offer plans to the public view.
Including the process of design from scratch using Rhino.
This is something which could be done -at least- inside of this forum.
So, you guys, you can have a look at every single step and add your comments.
Please let me know if you agree with the idea.

Regards
Eric

[bertho]

eric,
if you are just beginer in boatbuilding, be very carefull regarding your estimate for weight,(for steel option especialy) and cost, so many nice project are almost sank before to be launch.. and so many never launch du to $$$ shortage, ( hull and deck are only some 15%to 20% of the final cost !!)
all the best ! it a nice project
bertho
(apologise to for my frenchiglish ! )

[Barbaros]

Bertho,

Thanks for your encouragement and don't worry about your english.

Regards.
Eric.

[bertho]

Eric,
HI, why you don't like fiber glass ??, look the picture as attachment, it's a small fishing boat i built in my shipyard in Quimper some... 10/12 years ago.. all done with flat panel mold with gelcoat on table, with skin thinkness decreasing on edge and on the bended place, all assembly done on a cheap provisory wooden form, and all structural frame/bulkhead laminated inside, it's was quick, strong, nice looking and cost effective for one-off product, without any tooling cost.
My advise for your project will be to deal with a shipyard ( my old one is still in business) and order just the hull and deck, even if you can complete the boat by yourself...the final value of the boat will be much better than a "amateur built pedigree"
best regards
Bertrand d'Alencon

[Barbaros]

Hi Bertho,

Thanks for the picture.
This is a very nice vessel and an excellent idea.
Right now I am in the office ... working hours ...
Let me read again and I will back pretty soon.

Regards.
Eric.

[M&M Ovenden]

Bonjour Eric,
To your question “Are you insane?” I certainly think so, but many people function very well with overwhelming project and depress in the wise world of “do what you should do like everybody else”. I am quite deep in my own project and even though I find it hard some days, it's going well, so it must be possible.
You should really only ask yourself why you want to design and build your own boat, as there are many answers, the only good one being because you want to experience the quest, the worst answer being that it's cheaper (that's not true). Make sure the whole process will provide you satisfaction because it takes a lot of will and discipline and won't happen if there isn't a part of fun.

I have worked out my boat threw the Dave Gerr Scantling rules to get the large idea but then also worked it out threw ABS rules. I found the Dave Gerr rules very neat but also found it tends to lead to very heavy scantlings, which is only fine if you take it in consideration in your weigh and balances.
I would be curious what view “true” boat designers have on those Scantling guides.
Have you considered building your hull in steel and superstructures in epoxy/ply or aluminum? I think that boat would probably be a good application for it.
For a good overview on weigh/balance and hydro dynamics in french I found the tome 1 of architecture du voilier of Pierre Gutelle was a good book. It can be instructive for a motor cruiser aswell.

On the off chance your are going the designing route because you haven't found plans for the boat you wanted. Check out Micheal Kasten.

http://www.kastenmarine.com/nidaros.htm

Bon vent,
Murielle

[Barbaros]

Hi Murielle,

Thanks for your reply.
I was thinking to build upper structures using some more "light" and "easy to use" material. This is a good contribution to weight balance.
The "hydrostatics" from Rhino shows that for 80cm of draft you need a lot of weight which you can not get -only- with the weight of the hull itself.

80cm (31.5 inches) of draft needs around 10 tons.
The steel used for the hull weights only 5 or 6 tons (approx).
I am going to put the plans progressively into Internet.

Would you tell me a little bit more about "architecture du voilier of Pierre Gutelle" which i never heard about.

Again many thanks for your reply.

Kind regards.
Eric.

[Barbaros]

This is another project.

[Barbaros]

Sorry ... some pictures are missing ...

[M&M Ovenden]

Eric,
You can get or find out more about the book threw Loisirs Nautiques
http://www.loisirsnautiques.com/index.php?page=librairie_horsserie_rech
Being in France, if you order it it will be at your door within a couple of days.
The book is very graphic, everything explained has squetches and graphs. The first volume goes pretty much over what you need to know to start understanding all the implications of the hydrostatics data marine software privides. Depending on your math understanding you will get more or less out of it. No matter what it is very clear and goes over hull shapes and weitgh distribution and how it influence balance of a boat. On the more geeky side of things it goes threw the hydrodynamiques of hull, rudder, keels.... Their is some part more specific to the sail boat, about balance the underwater and rig but most of it can be applied to your project.
For the english folkes, I think the book is also distibuted in english, but I don't know if it's the integral content of the French version.

Murielle

[burak.acar]

Thanks Eric,

why dont you use my e-mail for further cooperation?

(info@poseidonltd.com)

Looking forward to your reply.

Burak.

[marshmat]

Hi Eric,
A quick note about weight estimates. While the hull itself is a pretty big contributor, don't forget about engines, gearboxes, rudder gear, batteries.... and of course interior furnishings, doors, windows, stairs.... then there's cookware, appliances, foul-weather gear.... stuff really builds up. It's amazing just how much weight can be added to a boat through random stuff that you don't think of while designing. A 6-tonne hull, with a design displacement of 10 tonnes, has only four thousand kilos available for everything else- machinery, people, gear, etc. Getting the weight estimates accurate can save a lot of grief later.

[Barbaros]

Hi Matt,

Thanks for this precision. I was more vorying about the "ballast" and how to add some more weight to reach the required draft. But, I think you are right.
Still, the draft (sinking the propeller to an acceptable depth) appears as more problematic then the rest.
Even a steel hull remains very light.
For exemple, Rhino shows 20 tons ( 20 000 X 2.2 = 44 000 pounds) for a draft of 1 meter (39 inches). All surfaces togehter including the windows (!) in steel weights only 7 or 8 tons (17 600 pounds) which is very light compared to 44 000 !!!.

Regards
Eric.

[marshmat]

Remember, it's always easier to add ballast than to remove inherent structural and machinery weight....