1.2 m autonomous boat hull ideas?

@Tom - I'm out of town this week so have limited access to the internet right now, thus the reason for my delayed response. I'm interested in learning more about how your Rule 1500 bilge pump idea. Have you ever measured how much thrust they produce and how many amps they draw? I'm guessing I could use two so I could steer by adjusting port or starboard pump's RPMs? I'd loose the ability to go in reverse (without fabricating some reverse thrust device) but I could probably live with that.


@Portacruise - Yup, I'm also looking at kayaks as a possible platform. I've not found one that was under 8 foot LOA though. That's a great thread you linked to, I'll have to study that more when I get some time.

 

BK,

You said, " I finally have some time to invest in it and I'm hoping to nail down the design over the next week or so." in post #16 so I thought you were ready to go...

Rule 1500 is 2+ amps I think but you can Google it on their website. No, I never measured the thrust but the volume of water is impressive. Differential thrust would not be nearly as effective as a single, directable nozzle. But I thought you wanted to go with the prop... I looked into availability for Minn Kota props and it's pretty impressive including weed resistant designs. Water jets are horribly inefficient and may be a problem if you have limited battery weight allowance.

I think you should narrow down some of your variables and start some directed design work otherwise we're just all over the place and it's hard to keep up.

I'd need to know what you know about operating conditions, demands, objectives, budget, etc.

Stubby kayaks are less than eight feet but a lot of windage. I thought you wanted to minimize your windage.

If this rig is not totally autonomous then I don't think you really need my help here.

-Tom

 

I think you are seriously over thinking the boat design here guys. Since the boat itself isn't really important, I would just head down to the local yacht club and try and scavange an old dinghy of some sort. Think laser, opti, fireball, heck anything in the 6-8 foot range could probably be picked up for next to nothing, and will have more than enough reserve buoyancy for the mission at hand.

I am thinking of at least a half dozen boats I could probably get for free if I promised to just go get them. Even a cheap roto-molded kyack from west marine would be fine.

 

Have you looked into http://www.duckworksmagazine.com/ for a single sheet design?

or expandcraft

and then there's always just using a big truck tire inner tube but don't think that would make 5 knots. it would make for a very fast floating test platform though! Test out all your other gear on the tube then xfer it over to the hull of choice when you finally spec it in. You could be operational in about an hour. Or do I have entirely the wrong picture of what's going on here?

 

S & S,

You're absolutely right. There are lots of 5 knot platforms out there to choose from.

-Tom

 

Thanks guys, I think I've gotten the info I need.

 

This looks nice and should be an easy boat to build. You just have to scale it up to the size you need.

If you are still interested in my one sheet Little Sailor let me know though I think it has too much rocker for your purpose.

 

Hey flo-mo, thanks for following me here to this thread! I like your little sailor, but I think you're right about the rocker. I think I might try to recreate the lines in freeship then straighten the rocker a bit, give it a vertically plumb transom and a full deck. I'll then play with the dimensions to see just how narrow I can go and still keep it under 6 feet. If you don't mind my asking, what software are you using to layout/plot your plywood panels?

 

Not done with ideas yet!

How about a Proteus type craft? Like the rebelcat use pvc for the pontoons, foam and glass the bow and cap the stern. Another center pvc pod can house the electronics on a slide out panel. built in waterproofing .......The whole craft can disassemble for transport and storage. This can handle a trolling motor and car battery or you can adapt a jet drive like you were asking about using a bilge pump.

A question: Is this a work horse research vessel or something for show?

 

@spidennis - I considered a wave-piercing design, but at this size I'm not sure there'd be much advantage and I'd need pretty long hulls to handle any weight at all. The goal is to produce a working prototype and test bed for some electronics I'm designing.

@flo-mo - I like that Glen-L design but because the bow has so much rise/rocker, I'll probably need to cut it down so I can add a full deck. Love that hull weight, 4 lbs.

 

So BigK, what did you come up with over the week, any final design?

-Tom

 

@Tom - Not really. Still bouncing around some ideas.

 

Aha, well, I found the semi-submersible I was looking for. This is way overkill for your budget but the idea is sound. Providing you don't have any shallow water issues.

www.ise.bc.ca/dorado.html

If you search around a bit you'll find some footage. There were several news clips, a feature on Daily Planet on Discovery Channel, etc.

-Tom

 

I'm familiar with the Dorado project which was similar to where I originally thought I'd go with this project, but I started having second thoughts when I considered how I was going to maintain the vessel's neutral buoyancy in various conditions and water densities.

Not sure where my "ultimate" design will go but ran into this project a few days go which seems to work quite well:

http://www.youtube.com/watch?v=7P2HiD-d1Ok

 

"10 foot SWATH" is another thread you may want to search out here, on this forum.

-Tom