Stopping 140,000 lbs

Not sure if anyone here can answer this question, but I am thinking about building a 24'x48'x4' construction barge. The barge will have a 10" light draft. To enable me to work in shallow waters I have entertained the idea of putting twin Yamaha 300's, with a low pitch 4-bladed prop.

My concern is not if these motors will get the barge in a forward motion, but rather will they have enough prop/HP to stop the barge and associated equipment. The weights of equipment that may be involved are as follows.

Barge: Appx 50,000 lbs
Crane: Appx 60,000 lbs
Misc Materials on Deck: 20,000 lbs
Total weight: 130,000-140,000 lbs

I know that typically a diesel powered push boat would be ideal. But the barges will be sectionals, each with its own helm. This would allow me to separate the 2 barges for smaller jobs where I would use my smaller equipment.

 

You can stop these puppies with a paddle, eventually, but the real question is how fast do you want to stop. You'll also want to think about maneuverability. Outboard wills work, but they'll beat the water to a froth, more then propel your barge train. High spinning outboards will want to scoot, even if under propped. You could get a much taller gear set, but this is a significant added expense on top of the $40 k for the outboards. If dropping this kind of change on a work barge, why not something more suitable and more durable too. You could run a PTO off a diesel (for whatever), a straight shaft and yes, you'll pick up some draft, but the barge could also have a prop tunnel and duct, offering some protection and shoalness.

 

I've also been looking at a 32' push boat. It's got twin 454 engines, but it has jet drives. When I think of jet drives I think jet ski, but I know that they are running jet drives on some of the bigger yachts now. I've heard they'll move a bunch of water. I like the idea of the jet drive bc I can still get pretty skinny. It's going for a pretty good price, $22,000 is asking price., which is what I'd pay for 2 used 250's

Opinions?

 

Considering that you probably only move the barges occasionally from job to job, a gas engine is not a bad deal. Particularly when you consider that a long block is $2500 or so and will last you 5000 hrs.

 

I would think a barge shaped like that would slow pretty fast without any reverse thrust. what you need is a way to maneuver it near a dock, and control it when in tight quarters. small outboards would work, but would be slow to get that much mass to react.