River Boat Design

Yep, that's almost exactly what I'm talking about!

 

Yes, I realize the buoyancy would be less with the tunnel, but the tunnel will still allow shallower running. Every inch makes a huge difference when the water gets skinny. Some of the buoyancy/displacement can be overcome with flotation pods on the stern, and trim tabs can also assist in getting the boat up on plane (see original post). I've incorporated a hydraulic jack plate in the design to take full advantage of the tunnel; otherwise, without a tunnel, much of the jack plate is wasted.

 

I took the liberty of adding a tunnel, and a couple of bouyancy chambers aft of the motor mount. 1: These will support the motor 2: they will cut down on spray (hopefully) from the shallow prop and 3: will allow easier entering and exiting of the boat by having a folding ladder on one or both sides. I stuck a center console on and added the Specs in a .txt file too.

steve

 

National Park status excludes hovercraft because hovercraft can go where other craft dare not tread. The park system did not want to become obligated to rescuing stranded hovercraft, as that would require purchase/use of yet more hovercraft for the rescue.

Cell phones have increased the obligation to rescue people, before cell phones the Park system would recover dead bodies from the river (flash flood common thing certain times of year) as much as rescue live people.

I'm not sure what your payload requirement is - would 700-800 lbs be anywhere near enough (4-5 people)?

For those who venture into the back rivers of Alaska where dependablity of automobile engines and low fuel consumption is important you might want to click one of the links below.

http://members.aol.com/sevtec/sev/skmr.html

Geoduck:
http://members.aol.com/hovtec/hover/GEO.html

Note-1: I am not associated with this maker, but do admire the design (low noise and takes on big 15 foot waves).

Note-2: My hovercraft skirt lasted 15 years (different craft) - not too shabby.

 

I just though I should mention the elevated center console model Sevtec - hope you don't mind the hijacking.

Link:
http://members.aol.com/sevtec/sev/CUST.html





Good luck with your boat design - it's looking nice so far.

 

I wonder what one of these would go for at an surplus auction.



From here:
http://www.defence.gov.au/dmo/news/ontarget/sept05/nb4.cfm

Also found this:


http://www.hammondfishing.com/ponte-vedra.htm

 

Yep, that boat is almost perfect! That's what I'm looking for.

I'd maybe make the tunnel a little narrower - I think 14 inches would probably be wide enough. I'm also thinking the tunnel should be as wide at the front as at the rear, maybe even slightly wider...

 

I've seen those National Guard Bridging Unit jet boats in action. A little too big and heavy for what I need, plus it takes an experienced crew just to launch and load the thing! Interesting concept, though!

I've actually been on a Carolina Skiff before, though not one that big. They seem to be a pretty average boat, as far as shallow draft boats go. There are boats out there that go shallower (try googling for "flats boat" to get an idea of what they use in skinny water on the coast to get to redfish). Plus, I don't believe they build the CS in aluminum.

 

just get one of these with a jet.......you can get them 22ft. and 72 wide

 

Once again, jet motors will not work in this river. There is a LOT of fine suspended silts and sugar sands that will eat up a jet impeller rather quickly (unless it's one of them big ol' reversible Hamilton jets, maybe...)

 

Go simple rather than complex.

forget the tunnel - the boat will only be a few inches deep unless you make the boat heavy and complicated like some of the pics above.

It is likely the tunnel will take the prop above the static waterline, so it will just suck air - particularly if you have to reverse thrust at any point. An outboard is the simplest solution - just swings up.

5ft beam indicates something simple, relatively light. This also indicates a minimal need for power.



The one in the pic is to carry low loads but if you look at the page reference below it will show some other versions of the same concept. These boats run well with heavy loads anyhow.

A 10hp outboard would drive a simple box hullform of those proportions at a cruising speed of over 10 knots with a few extra in reserve. this is the benefit of the narrow beam, generous length and light displacement.

Box hullform gives good static stability. If run very fast and turned quick such boats can trip and roll.

Seakeeping is good providing that the hull bridges several waves at once. If it starts climbing up the face of waves and dropping off the top it will knock your fillings out if you do it at any sort of speed.

Phil Bolger had his IDAHO - it is a bit longer than you are talking about but the beam is in your range He has designed quite a few boats of this concept and they work well - I have used them a fair bit and have drawn up a similar boat.

Some examples ...

http://www.alaska.net/~fritzf/Boats/Sneakeasy/Sneakeasy.htm

Some commentary on the type of boat (mine) including how they actually go in real water.
http://members.ozemail.com.au/~storerm/Dayboat/Dayboat_Launch.html

Michael Storer

 

where r u frm?

 

Sounds like we are going back in time.

http://www2.richland2.org/rce/transpor.htm

Most cities have rivers going through them, populated and developed long before dams bocked the river, highways went around or through them and airports connected them to the rest of the world.

I live in Ann Arbor Michigan - home of the University of Michigan, back in the 1800's the Huron River was used by over 100 foot long "Cargo Canoes" to help supply the growing city. I have seen the pictures of these cargo canoes because I've done some historic preservation work as an architect.

They really piled high the cargo, and there were lots of them. These boats were different than the cargo barges of the Erie cannel.

 

mrdancer,

Are you looking to build this or purchase something that is already made?

 

what sea arc? they make a big *** johnboat,Pics look neet (where is that) ?