Ocean Stability of a Box-Shaped Barge

I have been having some heated discussions recently about the ocean stability of barges on the open seas and wanted to get some feedback from the experts on this forum.

The proposed vessel would be large, 500 feet long, 90 feet wide, and 50 feet tall shaped like a rectangular box (all right angles) for optimal cargo capacity. I would like to get feedback on how stable it would be in choppy water crossing the ocean were storms to occur (including worst-case scenario, a hurricane), what effects the draft, flat bow, and flat-bottomed hull would have on weathering wave impacts, and whether it would be prone to capsizing. Would sufficient ballast allow it stability?

 

Hello, welcome to the Forum.
Structurally, 500 feet is a bit long for the depth of hold (50 feet), but ok. Seaworthiness, though, would be more a function of stability; which is a function of weight and its distribution. Could it be designed to work? Sure, Noah did it; and there are towed RO/RO barges that size that operate in the Caribbean. FWIW, rake in the ends will help seakeeping and wave slap; which can be 10's of thousands of psf. See https://www.hse.gov.uk/research/rrpdf/rr324.pdf

 

And a second welcome from me.
Will this be a flat-top barge, or will you be able to carry cargo inside the barge (like an open hold on a ship)?
What type of cargo do you anticipate carrying?
And which sea / ocean will it be working in?
You definitely want to have some shape in the ends of the barge, to reduce your resistance when compared to a purely rectangular box - the slight reduction in cargo carrying capacity will be more than offset by the improved fuel economy of the tug towing the barge.

 

Would a flat-bottomed box-shaped barge be seaworthy?

It depends.

 

I'm a bit unclear as to what you mean here. Are you saying a 90 degree rake from a box-shaped barge would be workable, or that it should be adjusted? Also, is there a specific page or section in the pdf you're referring to?

 

A barge with cargo inside similar to a ship's hold, with heavier cargo concentrated lower for ballasting. Ocean would be primarily the Atlantic, would barge seaworthiness vary much from ocean to ocean? As for cargo, without going into specifics, I expect more tonnage would be needed for stability, so perhaps 20000 dwt minimum.

Even aside from the aspect of fuel economy, would the shape itself be seaworthy in the event of a storm?

 

Rake is the angle that the bow or stern transom makes with the baseline. A transom perfectly square to the baseline would have a rake of 90 degrees. Typical barge rake would be between 30 and 45 degrees for the bow, up to 60 degrees for the stern. If a surface subject to wave slap is at a rake of 90 degrees to the baseline, pressures of ~ 250,000 psf (i.e. 3900 fsw head) (read the reference) can be achieved, often many feet above the waterline.
Michelangelo: 12 April 1966 – Welcome aboard T/liner Michelangelo https://www.michelangelo-raffaello.com/en/michelangelo-12-april-1966/

 

A rectangular box-shaped barge would I believe have a 90 degree rake going straight vertical out of the water. Are you saying that degree of rake would take excessive pressure from wave slap?

 

The issue I am having involves the seaworthiness of a giant box design specifically, without deviations from such a design; no alterations in rake, bow, or hull for purposes of reducing wave slap, improving fuel economy, etc.

 

OK, how do you define seaworthiness - what do you think it should relate to, or include?
A giant steel box floating on the ocean is going to be fairly resistant to the forces that the ocean can throw at it, assuming that the scantlings are in accordance with regulations. It might well survive a hurricane at sea. And it might survive being washed ashore somewhere - but it would be a difficult job to then haul it off again. Look at the Ever Aground container ship that was recently (still is?) firmly aground in Chesapeake Bay despite the best efforts of salvors to re-float her.

But a giant rectangular steel box floating on the ocean is not much use to you, especially if it requires an enormous amount of bollard pull to tow it, when compared to a more 'conventional' barge shaped hull form.
And if you have two barges, one rectangular box shaped, the other conventional barge shaped, and they have similar cargo carrying capacity and similar stability characteristics, then they both will probably have an equal chance of surviving a storm at sea.
Fuel is so expensive these days that I would have thought that an efficient hull form re resistance would be one of the most important factors in the Statement of Requirements for any new construction of a barge today.

Re how you will have a hold inside the barge for carrying cargo, rather than having it on the deck as per a flat top barge - will you have hatch covers over the hold, or will it be open? If the latter, then you will need to specify some very good bilge pumping ability, such that it can cope with the worst case scenario that you can envisage.

 

Well, to be blunt, I am not thinking in terms of steel construction but wood, which I should have made clear from the outset. As such hull pressure would be more of a factor than for steel construction.

 

Wood? Really? Are you looking to build Noah's Ark?

Jokes aside, in one word - 'No'.
Don't even think about it.
J E Hardiman noted above for a steel barge "Structurally, 500 feet is a bit long for the depth of hold (50 feet), but ok."
You are pretty much on the limits here already with steel, and there is just no way that you will be able to build a wooden barge this size.
And even if you did design a flat top barge (this would have the maximum resistance to longitudinal bending, rather than one with a hold and hatch covers), the cost of building a barge in wood would be ridiculously expensive compared to steel.
That is why you do not see any large wooden barges anywhere.

 

If it's box like with sufficient weight at the right place it should work. but the design is suboptimal in many ways. obviously the waves will hit the sides at full force instead of the boat rising over them, the sides would have to be much more solid than otherwise. the flat surface underwater will make it harder for the boat to reach its speed limit and the boat will consume more energy in the process. the boat will also have a much higher tendency to drift sideways. It should aim to take the waves on the bow as any ship longer than wide do, but as its a really long ship, it might break in half. That's all I can think of!

 

Admittedly I am in fact looking for info on the seaworthiness of Box-Shaped wooden ark replicas like those owned by Johan Huibers and Aad Peters:

Johan's Ark - Wikipedia https://en.m.wikipedia.org/wiki/Johan%27s_Ark

While I was hoping to keep the discussion abstract without the controversy surrounding the Huibers replicas, I guess the fact that the boat would be wooden is a dead giveaway.

The question thus being whether a box-shaped Ark like those designed by Huibers would be seaworthy (although the fact that he used steel cargo containers as the frame was itself cheating a bit) as opposed to a more ship-like design such as the Ark Encounter exhibit.

 

I guess since the discussion is more or less derailed by the Ark controversy, I might as well point out that the debate arises because many advocates for a box-shaped Ark refuse to consider the recent Ground Penetrating Radar/LiDAR scans publicly released in September 2021 showing a framework of ship timbers over 6,000 feet in elevation close to Mount Ararat at the Noah's Ark National Park (Durupinar) recognized by the government of Turkey as the Ark's location because the scans show a framework built like a ship, not a box-shaped barge.

https://www.israelhayom.com/2021/10...aim-to-have-found-true-location-of-noahs-ark/

Noah’s Ark hunters claim boat FOUND in mountains using 3D scans https://www.the-sun.com/news/3725022/noahs-ark-buried-turkish-mountains-experts-3d-scans-prove/

There is a substantial population who insist that a box-shaped barge-like Ark was built by Noah, not a ship design, and that the new scans showing a framework of ship timbers cannot be legitimate. As such there are major debates going on right now over whether a box-shaped wooden Ark would have been seaworthy as opposed to a more conventional ship design more similar to the Eureka, Solano, or Great Republic.

List of longest wooden ships - Wikipedia https://en.m.wikipedia.org/wiki/List_of_longest_wooden_ships

Because the government of Turkey had some of its top scientists producing the scans, e.g. Dr. Fethi Ahmet Yüksel Head of Geophysics at Istanbul University and Dr. Salih Bahraktutan, Head Professor of Geology at Ataturk University, who are claiming the scans are not of a geological formation, it complicates matters for critics of the scans, thus the controversy. The scans are being featured in upcoming documentaries by the History Channel and Science Channel so they could feature more broadly in the news soon.