Boat for fast, shallow rivers

I grew up on the headwaters of the Amazon with the Machiguenga Indians. One of their biggest challenges is river transportation. Their dugouts, or modified dugouts, are heavy, slow, tippy and not all that durable. It would change their lives to have boats that are more stable, lighter weight, longer-lasting. I have no idea whom to contact for thoughts and feedback on my ideas, but if you know a designer who'd like a smaller project, please contact me: ronlsnell@gmail.com. I'm thinking strip plank core with fiberglass, but I'm ready to listen to any other ideas.

 

Depends on what they have access to as far as building supplies. I would assume that money is an issue so they have to work with what they have available... so what do they have available? Do they have access to planks or a means of sawing them? Where is the 'glass and resin coming from? Is plywood an option? Need more info to suggest a decent design. Strip planking is a laborious method of building...although you can build just about anything out of it. There might be easier/faster/more efficient methods but a knowledge of what is available is necessary to determine the best method to use. Do they use motors or oars or paddles? How shallow is the draft needed? What weight limitations are there?

 

Also, what obstacles above the water, such as overhead vegetation might interfere with propulsion system like sail or air propellor? Is motor fuel accessible? How are the boats used? General transport boats would have different design needs than fishing boats?

 

Boat for Machiguengas

Thanks for helping me think this through.

These are general transport boats--passengers and cargo. Since they are used on larger rivers, overhead obstacles are rare. Fuel is available but very expensive and hard to get, so fuel efficiency would be life changing.

The two most plentiful materials are lumber and labor. Plywood is available, but marine plywood would be difficult to come by. Fiberglass cloth and resins would need to be shipped in, but are "probably" available in Lima.

This genre of boat is used all over the Amazon basin and beyond. Although there are boats of this style with outboard motors, the vast majority are powered almost exclusively by "pequi-pequis" (taken from the sound of the motor), a 12 HP Briggs & Stratton mounted on a swivel pin at the back of the boat, so that the motor can be turned side to side and back and forth. A long drive shaft (12' ?) is bolted to the back of the motor and extends back into the water. A heavy steel tiller is bolted to the front of the motor.

So here's how you operate it: Lift the prop out of the water to start the motor, then lower the prop into the water and turn the whole assembly back and forth to steer. In shallow water, just lift the prop so it doesn't hit sand or rocks. It's a great concept and so universal that almost anyone can get parts or fix the motors.

BUT, the boats are so heavy that carrying capacities and fuel efficiencies are low.

So what I envision is basically a "modern canoe." Maybe 30 feet long with a 42-48" beam, designed for a nice compromise between stability and speed. An experienced designer could easily convince me that a catamaran style might be better, or something else even, but it can't get too wide because sometimes it has to negotiate narrow channels between rocks in rapids.

 

One more thing--yes, money is a factor. However, labor is cheap and durability could easily outweigh up front costs. I'm thinking of setting up a nonprofit to help provide these, so there may be funding to subsidize costs, at least for those boats that qualify as humanitarian projects and are used for schools, clinics, etc. Businessmen who ply the rivers would just pay full price for their boats.

 

OK, check the Thai longtail motors that are being discussed on other threads in this forum. They may be cheaper to run than some of the motors you have been describing. Airboat engines can be made using small engines 5-10 horsepower, but they can be dangerous in the wrong hands or in areas where children are present. Catamaran arrangements can work very well if the river doesn't narrow to less than 6 or 7 feet. Mud motors have a special foot that protects the prop against bottom hazards. These are small motors also but are designed for smaller piroque or duckboats. Where current is very fast, a land line might be rigged to attach the boat and pull it upriver against the current if manpower is available. I suspect wood is plentiful in the area you describe, so a local sawmill and carpenter may be valuable. Old methods like plank on frame and trunnel construction would still have merit in a society lacking in modern resources. Mallets, wedges and augers would need to be part of the learning curriculum of local carpenters. Boats locally built could then be glassed over with materials brought in. Wood chosen for flexibility and impact resistance as well as resistance to rot would have to be investigated. I hope some of this information proves helpful in your search.

 

You might find this thread either informative or confusing
http://www.boatdesign.net/forums/boat-design/amazon-river-loadum-up-26486.html

 

Lookup the WHO designed fishing boats for third world! They are free (the plans), easy to build and designed for being built by amateurs! Even the propulsion is simple and cheap!

And you can get glass and Epoxy in Iquitos!

Regards
Richard

 

Thanks Teddy, the Amazon river, Loadum up thread was very informative.

 

In this case I fear, it will be as confusing as informative.

 

I would suggest a lap built Panga style...designed in the 25-28 ft range with a 5 ft waterline beam, planking in the 1/2"-5/8" thick by 6-7" wide range...perhaps shiplap if the tools are available. Quick and dirty construction designed for a life of 5 years or so, replaced every 4 years (cheap labor...expensive exotic supplies not needed). Design the boat to plane easily...add a 3/4" hook to the aft 8 ft or so of the bottom to keep the nose down. I would expect the 12 hp motor to get about 12-14 kts in still water, +/_ with/against current.

Something like these (1st, 2nd) below would be good for about 2200-2350 lbs displacement for a 600-700 lb finished boat at 23.5 ft LWL, 26.6 ft LOA, Max beam of 5.9 ft or 24.8 LWL, 28 ft LOA, max beam 5.9 ft. Weight depends on construction materials of course.

Now...if you are looking at extreme fuel efficiency...displacement is the way to go (3rd). It is slower but uses far less fuel...the one below displaces 3550 lbs and would run about 1/4-1/3 the fuel consumption...but only about 7-7.5 kts at hull speed. Unfortunately ...waterline beam is wide at around 7 ft...but to carry significant weight you have to have volume somewhere. Going narrow(er) and deep(er) will only run into the same problems with stability that is already a problem though.

 

Slicer is the boat for you

The late Great Phil Bolger wrote the book " Boats with an open mind"he writes about a boat called Slicer , she is 29 ft LOA 5ft 2 in beam and she can produce 12 knots with 8HP outboard

I am sure you can get plans readily and you can be sure she will do the job.

 

The drawings are only illustrations of my points and not to be takes as pushing any specific designs other than what might be suggested in the text...ie "Panga Style". They are to be used simply as a visual reference to the opinion posted in the accompanying text.

 

Your milage may vary, boats in the mirror are langer then they appear. Not recommended for people over 60 or pregnant women. Has been found to cause cancer in clams.

 

Thank you!

I'm not commenting much because I know so little. But I'm following up on all suggestions trying to educate myself as to what's out there, so I genuinely appreciate the ongoing input.