Littoral Steel Trawler Design

14 feet of crushing material does not make a ship harmless.

 

This thread reminds me of the late, great, train carrying submarine, which was supposed to be built for the benefit of the downtrodden masses living on islands without seaports, but was really intended to serve the interests of the Australians in keeping the Chinese out of Oz by breaking any blockades which the PRC might throw up.

That train submarine thread was a hoot:

http://www.boatdesign.net/forums/boat-design/train-submarine-48728.html

 

The simple third world mini-trawler soon morphed into a remote control cargo ship. But it still has some catching up to do, to rival the train sub !

 

I don't know. Have you read the blueprints? They go something like this:
**********************
********************
****************
************
*********

 

The train thread should be revived. It's not fair to mankind to stop discussing such a revolutionary method of transport.

 

Concerning train thread comment:

The long slim design has a huge efficiency. 20 horse power can keep the 100 foot long version at hull speed in flat water. If the cost is 20K dollars sans engine what does that means?

It will not house containers, I used the container as a volume reference only.

Just special dollys to move inside cargo to the hatchway. First in last out loading.

The design stands!

$20K of work.

The press is also about 10K

Nobody in the history book can match this design. I am not going to state the welding lines at all. But it is eliminated cost wise. It has no compound curves but the U design ensures self righting. A barge version will not self right. This is a real hull.


The press hull is not in the modern maritime record.

 

100 ft hull speed is above 10 knts . do you really think 20 hp will do that. I don't.

 

Of course, all your previous calculations show no consideration for the stability of this vessel. A bote 100 feet long by 10 feet wide will probably spend most of its time upside down, rather than right side up.

You might have to add a second cargo hatch in that case.

 

Doug;

If you are really serious about this, the people you need to talk to can be found at this website.

http://www.fao.org/fishery/about/en

They collect, provide, and fund sustainable worldwide fishing and economic initiatives. Type in "fishing boat designs" in the advanced search and then click on the publications tab.

 

All kidding aside, I think one thing which is being overlooked is that, regardless of this vessel's supposed simplicity of construction, metal of any type is in short supply in some areas of the world.

One reason many old ships wind up on the beach at Alang and other parts of India and Bangladesh is that metal of all types is in short supply in these locales. The material salvaged from these old vessels often goes ashore to nearby villages to provide them with material the locals can use for a variety of things.

The islanders in Polynesia were very eager to trade with the first explorers for any kind of metal objects, including iron nails. The officers of these ships reportedly had to keep strict watch out lest their crews gouge out so many nails that their ships fell apart.

By using wood and other renewable and locally available material, a village can build a fishing vessel relatively cheaply with material and tools on hand, and not have to lay out capital to buy machines and material to build in metal.

 

NA, all this is very true but imagine if difficult to find steel to build the boat, how they will find engines or fishing equipment ?. Typically, these countries, which you're referring, not build modern fishing boats, when they want to renew their fleet quickly, they buy boats from a country that does know how to build. And, in many cases, the construction contract includes training for crews. It is to find a design that meets their needs, but they do not have to know to build it.

 

A boat 100' x 10' doesn't have to be unstable or unseaworthy, but it might not be so comfortable or dry !

 

well if it wants to stay upside down then the design should just be inverted!

 

For what reason the lenght to beam ratio affects the stability?

If I consider hydrostatics, the transversal stability only depends on the VCG in relation to beam and hull shape. Am I wrong?

 

I think so. KN values, which increase with the breadth, have much to do with stability. Not with the initial GMt but with stability as the ship is listing.