Newbie is building a river cruiser.....

[newinertia]

Hi guys, I have never posted before but have gained just enough knowledge
to be dangerous by reading threads in this site!
I am this morning buying 10 sheets of 5052H32 (4x10) and building the escape vessel of my dreams. I was wondering if you guys could give me any heads up advice on the caracteristics of this hull.
I am building it as a river cruiser of the most efficient means possible.
It is flat bottom, no deadrise and I have built the propulsion unit from a new 25 hp verticle shaft Tecumseh ohv mated to a lower unit from a blown omc
outboard, utilizing toothed belt drive sprockets for gearing capabilities.
I am going to try to post this design but I only have microsoft paint on my computer to draw with. (Anyone with Rhino skills want to help?)

[lewisboats]

Just an observation but I don't think the hull has enough buoyancy in the shape to work right...certainly not enough to to keep it from being lower in the water than you would want...unless you want the hull to sink down to second chine drawn. That would sure be a lot of wetted surface and not much freeboard. You also don't have the buoyancy forward to lift you over a barge wake (if you have them) so you would go through it...a wet proposition.

Steve

[newinertia]

Ok, do you think I should increase the side height from 24" to 30"?
I really appreciate the constructive criticism.

[newinertia]

Just an FYI- the drawing that is on this thread is a very rudimentary piece.
I know it will ride rough in a chop, but I am going for extreme gas mileage.
I am planning to get 20+ mpg. do you think that is possible with a 2.0 gal per hour burn rate and total hull wt. of 650 lbs?

[kach22i]

1. Rivers, some of them are shallow.

2. Rivers, some of them can have serious waves caused by barges.

From the hull shape, it looks like you will be cutting through waves rather than going over them. Therefore I assume you are answering condition number two as stated above.

Yes, no.......maybe?

The fun thing about rivers is stopping anywhere you want to, so you can explore, buy a soda pop, or take a pee. I don't see this bow working with anything but a raised dock.

[newinertia]

yes, I do expect to cut thru wakes and waves with the bow. I am under the impression that the flat bottom hull will plane easily and stay in its sweet spot for efficiency purposes, I may have to slow down on this craft when passing a barge, just as the trip I took last summer from KC to Jefferson City-250 mi. in my 15 ft Jon boat with a 25hp outboard, that is a mild tradeoff for the mpg. I am looking to extend the cruising time to dollar ratio.

[kach22i]

Originally Posted by newinertia

I am under the impression that the flat bottom hull will plane easily

I would expect that too, but the bow introduces the body of the craft to the wave, the stern (at full speed for most boats) does the planning part. I think you will have to do something to insure that the bow stays up no matter how pointy it is.

All I'm saying is there are two basic ways (most boats do some of each).

1. Cut wave

2. Ride wave (planning)

Cutting Example (in extreem):
http://www.armedforces.co.uk/releases/raq41ab090d825d9


Planning Example (not classic):
http://www.defenseindustrydaily.com/...index.php#more

[tom28571]

Let me see now. You will be getting 20mpg at 2gph. That works out to 40 mph on 25 hp in a boat made from 8 sheets of .125 aluminum. It has a 48" max bottom beam and 20' over all length.

I can't make any of these numbers compatible. The speed is way-way too optimistic. The weight is way-way too low. The mpg is way-way too optimistic. You can't just set these numbers any way you wish. They have to be the result of reasonable computation.

Other than that, everything looks ok if you like the looks. I think you need to read a basic book on boat design and performance plus a look at a table of materials characteristics.

Only your real friends will tell you.

[newinertia]

Thanks Tom- I appreciate the post, I somehow have caused a mixup on stats. I am designing from the standpoint of ease of build design,(low budget)
emphasis on cruising long distance, and a target speed of 20 in cruise, 28 at max. I have built a thick paper model and the lines are reminiscent of Dynamite Paysons Schooner. (instant boat) I found that by installing perfectly linear and rectangular sides as the gunnels flare it brings a natural up curvature to the bow. click on my link to see more 'hopeful performance figures'.
thanks
Skip

[newinertia]

Tom-
I have had the evening to consider the way and manner in which you replied to this thread, and is all I can say is- I am ashamed of you. I knew I was putting my design out there for opinion, but didnt realise there would be design snobs like you that would rather tear someone down rather than build them up. This is my first time ever posting anything on this forum, and thanks to your snotty remarks, I actually lost sleep last night. I am going to recommend to the powers that be, that you are repremanded and have your "Senior Member" status removed. You probably have never been to Kansas City, or been on the Missouri river, but I can tell you this design will work out just fine for me. The only boats on the river are flat bottom Jon boats! Thanks for making me want to expose nothing to this group ever again.

P.S.
Dont Ever Reply To One Of My Postings EVER AGAIN!!!
You are verbally Assaulting!

[tom28571]

Sorry you took my remarks as a reprimand. They were intended as a shock treatment and maybe I did not consider they would be taken so personally. While the design of a boat is a very personal undertaking, the physical facts of the design are not at all personal.

Lets look at a few. 8 sheets of 4X10, 0.125 aluminum weigh aproximately 570 lbs. The rest of the boat plus a driver, fuel, engine and other necessaries will bring this up a lot. Another 400 lbs just for the fuel. My guess is that you are looking at something more like 1,500 to 2,000lbs.

20 mpg is far more than anyone can get at planing speed in such a boat. While the first goal was 20mpg at 2gph in your post, that was dropped to 2.2gph at 20mph. Still far beyond what has ever been achieved in a similar boat.

A driver can expect to make the 28mph with a 25hp engine in a little shell of a runabout, or such, Your goal of matching that in a large river boat is not realistic at all. Whether your Kohler engine matched to an outboard lower unit can equal the performance of commercial outboards is another issue.

Yes, I have been on the Missouri and in Kansas City many times. I don't get any kick from blasting newbies on this forum. It takes time and effort to answer posts. Moreso as I am busy building boats. Just trying to get you to take a more serious look at the real problems you are going to face in this project. If you lost sleep over something someone said on a forum, you are in for some real insomnia later.

The internet is avery impersonal place and it's too easy to be offended. I've never had such a nasty reply from anyone that I intended to help. Wouldn't stay here is that was the norm.

Peace.

[kach22i]

Originally Posted by newinertia

The only boats on the river are flat bottom Jon boats!

Did a Google image search on the term, exactly what I thought it was.

http://www.common-sense-boats.com/jon_boat_flat.htm


A slight modification to the bow with a slight upward arc is all I'm suggesting, much like the Jon-boat.

My 35 hp two stoke on my small hovercraft gets 2 gph. A boat even with a four stoke will do much more poorly, and far worse at the size you have proposed. tom28571 has made a good point, but he may need to work on how to deliver that message. His point is made and will not go away no matter how it is worded.

EDIT
You should see the "Idaho" and the "Sea Dragon", pretty close to your own proposal.

http://www.common-sense-boats.com/plans.htm

[tom28571]

The closest boat that I can think of that satisfies most of inertia's goals is Kilburn Adams Skiff America. Meets the speed and power but don't know about that engine setup. May work, may not.

[ted655]

Originally Posted by newinertia

Tom-
I have had the evening to consider the way and manner in which you replied to this thread, and is all I can say is- I am ashamed of you. I knew I was putting my design out there for opinion, but didnt realise there would be design snobs like you that would rather tear someone down rather than build them up. This is my first time ever posting anything on this forum, and thanks to your snotty remarks, I actually lost sleep last night. I am going to recommend to the powers that be, that you are repremanded and have your "Senior Member" status removed. You probably have never been to Kansas City, or been on the Missouri river, but I can tell you this design will work out just fine for me. The only boats on the river are flat bottom Jon boats! Thanks for making me want to expose nothing to this group ever again.

P.S.
Dont Ever Reply To One Of My Postings EVER AGAIN!!!
You are verbally Assaulting!

As a newbee you should be more receptine of criticisim. It's not snobery to point out basic design errors. It is very apparent to us that the design is very flawed, not going to be cheap to build, wastes space needlessly, has poor bouyancy/balance, will be uncomphortable and in general, IS a Wildabeast!
You are a "nut" & will surely drown yourself.
Oh... and I won't respond to anymore of your posts. You ain't paid ypur dues here to be that rude, dude.

[Brands01]

I am also a newbie designing my first boat.

Have you had a look at Freeship as a design tool? I would highly recommend it - very easy to learn how to use when you start playing around with it, and it will allow you to develop more complex hull shapes easily. You can also use it to develop your planking shapes which will be very useful when you come to the building stage (although it sounds like you might be there already).

Not sure if you've read much on the subject of design, but something like Dave Gerr's Nature of Boats is an excellent read, and covers most aspects of boat design and building - I have found it most informative.

Good luck, and don't take any rebuffs too hard - the advice here is good .. you'd hate to build a boat that doesn't behave like you want it to, as you'd never use it and wouldn't be able to sell it either