Dutch Barge long distance cruisers

Don't forget Selway-Fisher, if you are wise. I've a growing belief that their designs are truly first class. If you want to modify, I know Paul Fisher would be more than happy to advise and help you do so.

Regards

michael60

 

Hello all,

What I'm going to ask here is a bit off topic, but it is my poor-man's idea of a dutch barge, so here goes.

I have an opportunity to buy a WWII Sea Mule, basically a pusher tug for moving barges around. What I want to do is take half of it--they two identical modules bolted together-- and modify it to be a slow crusing, low CG humble house boat. See attached drawing.

A single module is 40' long, 6.5' beam, 3' draft and 7 ton. I'd cut down by the waterline, put 2 hard chines out horizontal to widen my floor space, as well as stabilize the boat, and then go straight up for a 7' high wall.

The bottom of the original hull would be for tanks, engine and ballast, if I need additional.

Yep, it wouldn't be the cutest thing out there, but it would meet my needs all around.
Cheap - I can get the thing, with engines, for 4,000 bucks
Stable - I cannot use a conventional pontoon houseboat, or flat-botton shallow river boat, as the lake I'll be on exclusively gets some big waves coming down the long narrow lake with nowhere to hide.
Trailerable - I can't afford, nor is it easy to get year-round moorage, and this boat, while big and heavy, would be within legal, non-permit, road limits and I only live 5 miles away.
Fairly cheap to run - It's got Chystler marine straight 8's in it now, but I'd swap to a Detroit Diesel 371 I've got laying around here at the shop

So, what do you think? Is cutting this old girl up and modifying it in this manner going to give me something that will give me what I want (which is a slow, stable house boat with 8' X 30-some ft sq of living space)?

If you think this folly, please tell me know before I arrange to low-boy this thing home!
~martin

 

Martinf

I'm no marine designer but I would be a little concerned about stability here. From your sketch, it looks a tad top-heavy.

Also, is this actually going to be big enough for you to live comfortably? Unless you are alone, it offers less living space than a very small English narrowboat would.

Since you only live 5 miles from the lake in question, does it really matter whether it costs a few bucks to have it low-loadered to the launch? If not, then you could use both modules - or even split them and re-assemble at the water's edge together with superstructure.

Just my unqualified opinion, of course. It will be interesting to see what others think.

Best of luck

michael60

 

Would the "hull" 1/2 remain the hull? The same form underwater? Below waterline is always designed for just that, to be strong & smooth "in the water".
Side decks are a necessity on a big boat, where are yours?
IF you are cutting the top off & keeping the bottom, then you're on to something. If you are throwing the bottom away, then (GULP!), good luck.
I always wanted to build a shallow hull, ballasted with concrete and bolt a shipping container on top. Fabricate a wheelhouse in the middle and have a cheap house barge.
We aren't far apart it doesn't look like.

 

Michael60,

Thanks for the input.
You're right, it isn't real big, but I'm not going to be living on it, just a week or so at a time. And the 8.5' beam keeps me in trailer country.
Not splittling the hull and keeping it as one doublewide and low-boying it isn't an option as it would be just to expensive each time (lowboy time and crane time both ends to load/unload probably set me back 300-500 bucks every time I wanted to use it!).

But, the top heavy question, ahh, now that's something I need answered. And will need to learn how to do this math. I'm hoping I'll be able to get some pointers on this site. But, for now I'm just looking for the basic opinions as to the soundness of the idea.

~martin

 

Yep, definately keeping the bottom as is. Specifically, I'm widening the top half 2 ft. This will expand my floor space.

I'm also thinking that by modifying the hull to create outward chines, this will increase my stability. Am I right about that?

Regarding the side decks. I'd like them but don't know how to have them and still keep my beam at 8.5....I suppose I could have narrow decks that fold up.

And yes, Ted, we're on the same wavelength here with this idea.

Other thoughts/concerns about this?
~martin

 

martinf

OK, I perhaps misread your original post in that I thought you had said you didn't want it trailerable. I was wrong in that respect, I see. You DO want to trailer it.

Looking again at the problem, I see you have 6.5 feet beam. That's roughly the same as an English narrowboat. Why not go straight up from there? A chine is usually in the water, not at the waterline for the entire length of the boat. It's your 'chine' that makes for the apparent instability in your drawing.

Since you say you only want to live aboard occasionally, a 30 foot (or more if you extend the length overall, which is perfectly feasible) hull with a 6.5' beam is in common use on English waterways as a narrowboat. However, you need to think about those waves you mentioned and look for stability. Canal boats can handle some small waves but nothing too big.

I would still like to see some input from someone who has design knowledge, so here's hoping you can get a definitive response. My own instincts tell me that the original designer never intended this hull should function when unbolted into single units. Perhaps I am entirely wrong. Logic tells me that a houseboat from this design is perfectly feasible by either building on top of both hulls together or by splitting them into separate pontoons beneath an even wider superstructure than 13 feet.

Interesting post of yours. One that gets the little grey cells to work. Well done.

Regards

michael60

 

I was widening it out a foot on each side to give me more floor space, but also thinking that that would add more stability, not less. Granted, it does add to the top heavines issue, but doesn't widening it make it less likely to roll over IF that widened chine portion is in the water? If that horizontal one ft chine were up in the air, yes, it would reduce stability, but if that part is down in the water, I'm thinking that that acts a bit like adding outriggers, so to speak. I guess one would have to factor the increased stability due to hull widening against the decreased stability due to extra top heaviness.

Or am I not viewing this correctly?

 

It can.... depending. Hunt up the thread on "tumblehome", here on the forum. Read that thread.
What keeps a boat from rolling "over" is the bottom is heavier than the top & the mechanical advantage between the 2 is low. That advantage can be wind, waves, cargo, sails, troughs in the ocean, etc..
That being said, there are equations to "guesstimate all that, but to be really sure, a model must be tank tested.
Ballast in the bilge & a air tight chamber on top of the cabin are good starts for us amateurs.
Dave Gerrs book, "The nature of boats" ougt to be in your library.

 

Great, Ted, I'm on it. Just found the thread and bought the book (dontcha love the used section of amazon...)

And, what you said makes total sense. I think I'm already there: beefy, heavy steel hull below, light house thing on top, but not too high up. And stabilty adding chine width a bit below the waterline. I realize I need to do calcs to figure out actual draft, but where should that chine be...at the waterline, just below, or deep in?

Thanks for your help and a blessed Thanksgiving to you all.
~martin

 

It would float very well the other way up!!!!!

 

Well said, colinstone. I had thought of putting that view forward but persevered with trying to find some way to make it work.

Fact is, martinf, that most boats ARE the other way up - unless they capsize, of course.

 

I think the chine should be deep into the water, but freeboard is a consideration.
Here, in the calm waters of the swamp, most skiffs are 18" to 21" deep. So when they set their freeboard on their floating cabins, they try to hit @ close to those heights. That way they can load & unload directly across from deck to deck. No big step up or down. The cabins are pushed to & from with the skiffs, it helps if both are the same /close height above water line.
As an example, my houseboat has a 30" freeboard. I would do real damage if I tried to push it.
At the point where you decide to add chine, will this be @ the bottom of boat & will you then add short vertical sides, & then angle out & up or is your plan to continue from point of hull bottom "out & up" at a angle until l you achieve your desired deck freeboard? To do the latter will give you too steep an angle in order to keep the desired boat width. Another choice would be to add short angled sides 1/2 way up & then add another vertacal chine (1/2 submerged, until desired freeboard is obtained.

 

I know, I know...it does look weird. it's just that this metal hull meets my needs pretty peerfectly: 6.5' wide so I can trailer it, lots of freeboard...and cheap!

I just gotta believe there's a way I can take this hull, modify it as need be, and put a bit of a house boat in it and somewhat above it.

I am going to put some sweat into this by understanding and completing the basic calcs, perhaps even learning FreeShip, so I can ask some educated questions of you good people (and perhaps "earn" some answers from the engineers gracious enoguh to give advice on this board).

Right now I'm much better with a torch and rod than a calculator...
~martin

 

Hey martinf

What's happening with your plans? Any news on what you are gunna do?

I truly hope you've resolved the problem by now and have the project well underway.

Best wishes

michael60