Might have to build barges.

[gandrfab]

I have a customer that is interested in 3, 8' X 40' barges, that will stack on a trailer then get craned into the water and assembled as one 24' X 40' barge. He wants a 3' free board

He works in the movie and filming field, Here is a link to his current boat. http://www.cameraboat.com/

I have built a lot of aluminum air boat hulls, this would become my largest job.
The barge may spend up to 3 months in salt water, what alloy would best suit his needs?
Is 1/4" plate thick enough for this application?

Any advice is helpful, Thanks, Matt

[gandrfab]

Made a call, and a bit of math, looks like if I use 5052 1/4" thick the sections should weigh around 4500 pounds each.
(is my math close to right?)

Can anyone tell me about where the water line might end up?

Thanks

[welder]

You need to get a hold of member kmorin he can answer your questions on material and filler metal.

[ReelSong]

I believe chris Tucker told me once that 1 cubic foot of displacement equals 60 lb.s of floatation, but I'd email chris or Kmorin to be sure

[gandrfab]

Paging Chris...

Paging Kmorin....

[kmorin]

Matt, 1/4" is pretty much overkill so it will work, but is an unneeded expense. Designing the three barge modules is not all that hard but should be done by someone with some experience with modular, pin together barges or docks.

The interlock system and the loading of equipment need to be known, how it will be towed, anchored, moved, stacked, and other few dozen other items are not addressed so materials scantlings can't be assigned with too much accuracy.

Some facts that are pretty obvious are *the entire set of barge/modules would form their own trailer all that was needed was some tow hitch and some axle sets to attach. *The set of three modules needs more interconnection design than 'box' design as that is what will be 'loaded' when the entire barge is afloat. * decking versus cockpits, internal volume use versus deck loading would need to be known before you can even discuss the project.

most of all the main info is not here to reply too, I'd use 5052, 5086 or 5083 for anything that floats in salt, if I could, but there isn't enough info to reply to well about much else?

I'd say you'd need to know if the barge was all deck or well decks? What is the all up loading ? What is the use description? [The link shows a planing cat! it will take some decent push to plane a scow this size!] Will the barge set and haul it's own anchors, will it be moored or on the hook? Will other boats come and go, dock and leave? Will there be a seaway where the barge is used? What are the seas likely to be worst case? well you can see that in order to answer a question it would be necessary to have some idea about the use and design

If there are three cubed rectangles of solid 1/4" plate and an interior median support deck to hull along with sufficient transverse framing and sufficient pin and joining metal this will work. Not much useful information there.

I'd start with some sketches of use and connections, then work to see if the client can live that arrangement? Then I'd go back and forth with the client and the structural design to make sure the barge(s) don't have more in them than needed but the client is onboard with the design. That's all just to give a bid.

Cheers,
Kevin Morin

[gandrfab]

Thank you, the barge as I understand should never see seas bigger them 2 or 5 feet.

[kmorin]

Matt, a 5' sea for the barge connections implies some decent engineering!

The 'boxes' themselves are not too challenging, but I'd do some looking for an existing professional design office that has done modular barges in alloy. The reason is that if you build the barge and something goes wrong, the film guys will have your proverbial "stern in a sling".

My idea is to contact David Pascoe http://www.yachtsurvey.com/ the marine surveyor and ask for recommendations for design offices in your area that have either Mississippi River modular barge background or something similar.

Is this project out of pocket for the film people? If so, then the plans and insurance issues may not arise, but if they're backed by a studio or have bank financing then plans, weld qual.'s and all that usually apply? Best to check now before having officialdom descend on your shop and begin to be intrusive.

CG too, they may have some input and all these details are what makes the type of project you're describing, less than simple.

Officially this is a Non-Trivial Event (november-tango-echo) project.

Let's go back to the design questions that you'll need to solve. I'd get with your client and someone that knows boats (towing, mooring, tide and weather planning, anchoring, locations, .......) and ask some serious questions and get some commitment to facts. Without that level of detail no responsible designer will participate, if the client won't get exact and explicit, professional design offices realize they will have to "fill in" all the details and spend serious (time=dollars) effort to get each and every detail resolved.

To be fair to you and your client a "sit-down-and-sketch" session seems like it's missing?

Cheers,
Kevin Morin

[gandrfab]

Yes, and Thank you
He has been hinting about this barge since I built the aluminum tower on his boat 5 or 6 years ago http://www.cameraboat.com/ that comes apart and folds down so he can trailer it all over the USA.

If this does happen I'm not doing the work for Universal Studios (but I have welded on a few of their boats) I'll build it for a single person. He is not in a hurry, but I do need more work.

[gandrfab]

If this does happen I do expect to over kill the connections.
I already know it can't have a hinge or just on top connection it will have to seem like a single barge when assembled.

[gandrfab]

Matt, 1/4" is pretty much overkill so it will work, but is an unneeded expense. Designing the three barge modules is not all that hard but should be done by someone with some experience with modular, pin together barges or docks.

I agree it should not be that hard, I have to start some where.

The interlock system and the loading of equipment need to be known, how it will be towed, anchored, moved, stacked, and other few dozen other items are not addressed so materials scantlings can't be assigned with too much accuracy.

interlock system, I don't know yet
loading of equipment, camera crews and actors (maybe a helicopter)
how it will be towed, his one ton dodge using a flat bed trailer
anchored, with anchors from cleats we have not made yet
moved, trailer, tug, pushed with one of his other boats
stacked, crane like typed in my first post

and other few dozen other items are not addressed so materials scantlings can't be assigned with too much accuracy, Hence why I am asking

* decking versus cockpits, internal volume use versus deck loading would need to be known before you can even discuss the project.

almost a solid deck, with just a man hatch in each section.

most of all the main info is not here to reply too, I'd use 5052, 5086 or 5083 for anything that floats in salt, if I could, but there isn't enough info to reply to well about much else?

It is a floating box that will see salt water and fresh water, what am I missing?

I'd say you'd need to know if the barge was all deck or well decks? What is the all up loading ? What is the use description? [The link shows a planing cat! it will take some decent push to plane a scow this size!] Will the barge set and haul it's own anchors, will it be moored or on the hook? Will other boats come and go, dock and leave? Will there be a seaway where the barge is used? What are the seas likely to be worst case? well you can see that in order to answer a question it would be necessary to have some idea about the use and design

The link shows a planing cat!, that goes 74 mph
it will take some decent push to plane a scow this size!, no plan on a planing barge
Will the barge set and haul it's own anchors, I would bet no one else will do it for it
will it be moored or on the hook?, I would think so
Will other boats come and go, dock and leave?, how would the camera crews get to the barge when it is working?(helicopter seems a bit expensive for every trip on and off)
What are the seas likely to be worst case? mostly lake work but I think he will let it see 5'
well you can see that in order to answer a question it would be necessary to have some idea about the use and design, trying to work on that.

If there are three cubed rectangles of solid 1/4" plate and an interior median support deck to hull along with sufficient transverse framing and sufficient pin and joining metal this will work. Not much useful information there.

If this happens, that sounds like the plan

I'd start with some sketches of use and connections, then work to see if the client can live that arrangement? Then I'd go back and forth with the client and the structural design to make sure the barge(s) don't have more in them than needed but the client is onboard with the design. That's all just to give a bid.

Cheers,
Kevin Morin

Thank you for the information and your time.

[kmorin]

Matt, here are a few concept sketches to work from



first all three sections are the same size so the resulting barge is uniform top and bottom and length. These boxes would probably float in a few inches of water, but that displacement can be calculated once the shape is firmed up. The ends allow towing from both ends and anchoring in a swell, not that you'd need the consideration in a lake.

This may seem the logical build, but defining the project more, getting a day's work use pattern defined is pretty important so the resulting project isn't under constant cut and weld- modifications to accommodate provisions not included in the design?



Another idea may be serviceable and reduce the overall size of the (highway) tow and still give more than adequate deck room That is to make the center module deeper so the three elements have a shape with one deeper hull and two shallower hulls, this will tow on the water much more reliably than the first example but will take a bit more crane work and assembly when rigging up to use in the larger, full deck size.



last thing to mention is the fact that these three boxes singularly or stacked will be structural in between swells so they're sure hold themselves up to trailer. The two idea for hauling as shown in concept (cut and paste) form just to illustrate what I'm talking about in regard using the modules as their own trailer frame.

Stacking for trailering may be done by crane- but how each module fits to one another is as important as the assembled in the water pin system. I may not have made my question very clear? There is the action of stacking with the crane and the way the modules fit onto one another as in 'how they will stack' (due to the connections built-in for highway assembly)

Maybe the top module should be turned upside down to create a more streamlined pull? The deck edges may need recesses for chains, straps, bolt on fixtures or other considerations that are only used for the highway part of the barge's life?

Mooring to an existing set mooring or buoy and set anchor would mean the barge simply came to some location, picked up a bridle or mooring line off the buoy and had no need to handle ground tackle. The other alternative, hanging on the hook or using a barge mounted anchor big enough to hold this barge in a swell implies deck equipment and foundations within the hulls to handle a winch sufficient to haul and hold an anchor or sets of them. Due to wind and weather it may be realistic to consider four anchors for this type of barge in order to be able to put the barge in one place and keep a consistent orientation to the background, waves, light etc. (I'm not a camera guy but these considerations radically change the project so they'd best be at least discussed and addressed?)

Four winches, on the corners might allow the barge to position itself relative to light, (rotate in the water on the four anchor winches?) weather (shorten the anchor scope in fair weather and let out some serious scope in a blow?) and background (maybe the barge needs a changing angle the beach over the course of a day) ?

Some from of power and hydraulics is implied by a barge that handles its own hook (or hook spread) compared to one that is simply moored to existing anchorages done by others. So the project class shifts quite a bit, both structurally and mechanically if the scope includes self anchoring versus being made off to an existing mooring set by a service boat or someone else.

I'm not sure I'm helping or hindering but that is what comes to me when considering a project of this type.

cheers,
Kevin Morin

[gandrfab]

Thanks again
I have been welding for around 20 years, and a self employed welder for the last ten of them.
Not to much I haven't welded (well I haven't welded on a bridge) but I have welded parts that went to outer space.
I hope this will turn into another job, concept, cut it, weld it

[kmorin]

Matt,

Having done a couple of 40 scows (one piece- not modular) and built boats for a few years as well, my estimation is that welding is around 3-4% of this project.

Cheers,
Kevin Morin

[gandrfab]

Matt,

Having done a couple of 40 scows (one piece- not modular) and built boats for a few years as well, my estimation is that welding is around 3-4% of this project.

Cheers,
Kevin Morin

What am I missing?
It seems most of my welding jobs, welding is around 20% of the project.

[goatram]

Matt,

Having done a couple of 40 scows (one piece- not modular) and built boats for a few years as well, my estimation is that welding is around 3-4% of this project.

Cheers,
Kevin Morin

What am I missing?
It seems most of my welding jobs, welding is around 20% of the project.

Design!


So you will not lose the Shop. Cause if something goes wrong out on the water; No matter what; You Screwed up Not them. They have the money to prove it.

[kmorin]

Matt, the amount of welding drops proportionally as the vessel/boat/project grows. If you had one tower to do that you'd done before so the planning was done it would have some percentage of welding. But if you had a hundred towers the logistics, planning, coordination, transport planning, supplies, .... all the peripheral parts go up but the welding goes down in proportion to the increase in all the other aspects.

A 1000 hour job (boat) is about 7-12 % welding unless the boat is a two-three- or four thousand hour finished boat then the welding is 3-6% as the doubling or trebling of hours in all in other trades increases non-welding work.

You've described a self anchoring, but un-powered, modular, convertible barge (!) so my estimation of the work is that welding is the least, still super critical to completion, part of the overall work. "My" 40' barges were done as single big boxes and five guys with one welder did them in about 2 weeks each. But one welder could keep up with four fitters tacking up ahead of him. During at least five of the days the welder wasn't working full time as a welder but joined the fitters, so even then the welding in a huge all welded box was only about 10% of the actual hours.

However, in a 40' power boat, that boat took months and more people and the engine, shaft, drive, keel and hydraulics took as long as the entire hull in labor. I agree there was on the occasional TIG bracket done on the bench during the entire outfitting process but for the most part is was all install and mounting work, hundreds of hours of it. All the labor time was "diluting" to percentage of the project in the welding category.

If you build airboats, then what is the relationship between the 'bare hull' and the finished and ready to sell boat? I think the bare hull is a small part of the overall job? and welding is only a small part of that time. In lots of aluminum boats the interior fit out is twice to many times the work hours of the hull build. Two guys can move the entire bottom or sides into place, layout, fit and tack up in a morning, but those same two people can't even get the boat ready to paint, (!) or run all the wiring or even get the hoses ready for a small hydraulic job in two days, let alone 1/2 a day.

So I was cutting welding down to the proportional amount of the project that is implied by the scope I expect to see in the implied barge. Unless your client is going to move the barge(s) to another shop to finish and all you're doing is the rough structural work, then I'd see the welding portion as about 3-4% of the project; as described.

In a project like this, in my experience, I had to quit being the welder/fitter/shop guy and become the 'the Contractor' in order to make it happen. I found that I had to make sure all the parts and pieces came together, including as goatram mentions, the super critical plans from a final and agreed design; in order to make the project realistic.

I'd ask the (rhetorical) question of why do design offices and marine engineers exist? I think that once a project gets to certain level of complexity they pay for themselves with the details they plan and draw. I've built hundreds of small (<24') commercial net skiffs but only a dozen & some larger project boats, and many dozens of industrial systems of the level of complexity of a fully hydraulic modular barge. In my experience, once the level of complexity gets to a certain number of parts and pieces welding is only a small part of the project.

I've spent hundreds of hours of my time on designing projects in the past, and hundreds more on communications with suppliers of all types. I found that I could not leave the decision of the pump coupling spline adapter to an order entry clerk - I had to actually have someone knowledgeable of the hydraulics to make that interaction, for example. All this was needed to make the bigger projects come together, that's just what it took in my projects, so welding was just one more small fraction of the overall.

Cheers,
Kevin Morin

[gandrfab]

I'm not looking to build a planing hull or a cruise ship, just a barge.
Yes I under stand that pencil pushers have their place in this world, I just don't think a job like this takes an engineering degree. Some good ideas, yes. Some help from others (Trying to get some of that here). A big wig designer that want's big bucks, I don't think so.

Ya'll could help or not, I'm not even sure he will want this yet.
The first thing he is looking for is about how much it will cost.

[gandrfab]

kmorin, Thanks again.
From what I was asked we will have bilge pumps.
All he asks of me is the aluminum work he will take care of putting non skid on the decks.

[tazmann]

I'm a self employed welder myself " not on boats" and I would not touch this job unless it was engineered. If the customer gives you drawings and spec's everything that would be one thing but just giving the size he wants and the rest is up to you means you are 100% liable should anything happen. Big coin going into just materials engineering would be a small cost compared to the overall project
2 to 5 foot waves on a box shape 24' x 40' seems to me would put a lot of twist force on it ?
Tom

[CTMD]

You need to know/ask what he's going to load onto the decks as point loads will define the required deck thickness and masses will define stiffener spacings/sizes. To give you an idea this barge has 5mm deck plating and 3"x2" "T" stiffeners on 250mm (10") centers and frames at 1m (40") centers and gets small excavators (10 000lb) loaded onto it but you couldn't load some 5000lb cars on it as the tires are too small.

[CTMD]

Here's one I did before the show.

[NTGeorge]

Hey mate, it may just seem simple thing to knock a barge together. But hings arn't always as they seem. The logistics involved would be a nightmare. Where as if you went through a NA then you have the re assurance that it has been designed by a professional. And more than likely it will actually cut down your build time, as chances are they have designed one before, have plans that they can easily change to suit your needs. they should also be able to give you an idea on material costs and likely build time which can give you a much more accurate quote. Just build the NA's fees into the price of the job.

And to be honest you don't really need to go looking for a NA either as one has already been talking to you. You will not find a nicer bloke or finer NA than Chris @ CTM. Get into contact with him and let him simplify your life.

And good luck with it, remember the pic's if you get the job.

[pjay9]

In reading all of this I have received a massive education in what the business is all about! More power to all of you who do this! My hat is off to you.

Now one thing I can attest to is that if these 3 mods connected together are going to stand up to real 5 foot seas you are going to need some certified marine engineering. Observing ATB's and what that takes to hold them together, that is massive strength and forces to withstand.

I ran a 70x18 basically flat bottom boat this past summer in some lake conditions of 2 to 3 feet and it was a rough ride. So I imagine 3 of those side by side. Here's another example of forces...take a pool air mattress 3x6 and 6" thick, you are in the deep end...try getting up on it! The forces are extreme, even in that simple scenario.

MARINE Engineering...and if it goes wrong...the shop will not stand alone! JMHO! And observation from past experience in large Public Works Projects for the City of Tacoma.
I will be really interested to see how all of this works out.
Capt. PJ

[gandrfab]

I will be really interested to see how all of this works out.
Capt. PJ

Me to, now I have to convince him to do it this winter.