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psneeld · 19-02-2012, 07:14

hey...I'm not saying a plywood box wouldn't be relatively cheap...but by the time you so make it safe and realize a 25 hp engine wount drive it as you think....well keep the chin up for sure!!!

You might be better thinking pontoon (which can be shallow draft)...with a lowerable landing ramp...much like the old riverboat steamers. That may be driven by a much smaller motor and if you stay in sheltered waters or watch your weather...well that might get you closer. Some guy just did the great loop in a fast aluminum pontoon boat so it's definitely possible.

And I will say...better to do a ponoton boat with nice camping gear than to not get underway at all!!! And like I said...I've thought long and hard about taking a bike with me...now even on my 40 trawler!! But cruisin the waterways and highways all rolled into one is a sweet dream!

Git'er done!!!!

Wavewacker · 19-02-2012, 08:36

The most efficient hull design is one that is long and narrow with a flat bottom. A catamaran was my initial choice, in fact I got it down to Richard Wood's Skoota at 28' and we discussed ways to mount the bike. It would have been a build and that brings in the issue of money, time and skill, all of which are in short supply for this venture.

A pontoon boat is what it is, rounded tubes and not too efficient as a 24' toon will take about a 50hp to get it up on plane. While they make a good camper, they are not designed to haul heavy concentrated loads. The aluminum flanges are usually made in two pieces (][) and the 1/2 to 3/4 decks usually have a 2' span. They will carry a load dispersed over the deck area, but not a good idea for a concentrated load on a few square inches of motorcycle tires. A large plate would help for the bike to sit on.

The connections between tubes and decks are rather weak and not made for blue water. I saw a large pontoon sitting on the hard on the side of a hill, with its beam uphill. After a few days sitting there, it collapsed under its own weight rolling the down hill tube and tearing away the flanges! It was not a steep hill.

When you get in some heavy chop and wind, having a heavy load on a toon is just dangerous. I have run this by some of the toon manufactures as this was a thought long ago. About 80% of all pontoons manufactured are within a hundred miles of me, so we have them all over the place. The Tracker Party Hut is a great toon camper, but they don't advise loading it with a bike. A 4 wheeler is better on a toon as the weight is distributed over 4 fat tires, not two thin ones. With an 8' beam the height and CG of weight on a toon will not fair well in rolling seas or even rough lakes.

I mention this because I'd hate to see someone try it. But with camping gear and stuff they are a fun camp cruiser for rivers and lakes.

The best load carrying capacity will be from a monohull as cats need to be light to be efficient unless you get to large cats, like 50'. These are not my opinions but those of NAs and engineers/designers I have talked to about this project.

So, what has been advised is to go with a monohull with a narrow beam and some length. Bolger's Tennessee would be a good one, but the pointed bow, sharpie design make the landing craft set up harder. Bolger also has a tri cruiser with a removable bow that might work, but again weight is an issue.

Scows are the old work horse of the rivers and lakes for over a hundred years. The design is easy to build with a slight V or flat hull. They carry more in relation to the shallow draft than anything I can find at this length.

Bolger's Tenneesse uses a 10hp, cruises at 7 to 8 knots and uses a gallon an hour pushing the 32 footer with a 6' beam...much of this efficiency is due to the sharpie design and flat bottom. A 4 to 5' beam at the water on a flat scow hull will be very similar, and a box beam can be added forward under that blunt nose to cut water jsut as the Tenn. does.

In my mind, there would be a stability issue as I really want a flat ride, I don't mind the pounding, just less rocking on a monohull. So,I have asked about adding amas and to my surprise, there are scows with amas. Having the akas with some decking above would be a great platform to swim or fish from too.

Since I live in the heartland, there are not many opportunities to look for commercial boats as there are in the east or west coasts. If I did find a nice 30' work boat, the beam would probably be over 8 1/2' at that length as well as heavy.....so how would I get it home....$$$$$! This is what keeps driving me back to building, which is really something I'd rather not do, but not much choice.....that, or sell the house and move!
Maybe not yet...LOL

psneeld · 19-02-2012, 09:11

Every design comment you made is only a half truth....starting with that pontoons are round...many aren't ..I don't have the time to cover everything you said...but have at it and good luck.

Wavewacker · 19-02-2012, 09:40

Quote:

Originally Posted by psneeld

Every design comment you made is only a half truth....starting with that pontoons are round...many aren't ..I don't have the time to cover everything you said...but have at it and good luck.

Hmmm, I appreciate your input, like Paul Harvey always said, stay tuned for the rest of the story....LOL

No, not all pontoons have round tubes, some are made with flatter areas and chines, but all in all, are rare compared to most on the market. All production pontoons I have seen utilize a flange attachment to the deck, it could be modified providing a longer weld surface along the tube.
Some have aluminum decks over ply too, doesn't make the connection any stronger.

I probably should have said "most". A toon could certainly be beefed up. I have been on a couple toons on small lakes, like Lake of the Ozarks (LOL) and people have been thrown off pontoon boats around the Glazer Bridge, 4' and 5' swells. I like pontoons, but they are not as efficient as a cat hull, that's what engineers say, not my opinion.

Didn't mean to offend you at all, I have been talking about a notch above camping, but nothing like the fit, finish or amenities of your yacht. A pontoon on the Great Loop would be roughing it, IMO.

Should have mentioned that Glenn L designs a cat hull for builders, wood or aluminum that would make a nice pontoon boat, you could sling the deck lower for better stability and with the flat tops a better arrangement to tie in a good deck. But, considering the build, it's probably quicker with a scow hull.

**David M** · 19-02-2012, 09:50

I just noticed your title, Landing Craft Modified, LCM, is also what the military calls their boats, LCM's, or Landing Craft Mechanized.

Landing Craft Mechanized - Wikipedia, the free encyclopedia

Wavewacker · 19-02-2012, 10:29

Hi Dave, that was unintentional, I have been unlucky enough to have been in the LCMs on the Rhine/Neccar and lucky enough not to have been on one in the surf or off shore.

They are basically a flat scow but kick up further aft for a covered prop and rudder. Since I don't have the budget of the military, I'd rather not pay to cruise in one....LOL

Wavewacker · 21-02-2012, 06:48

Quote:

Originally Posted by hpeer

Take a look here.

I grew up with garveys, Dad's was 32' but no cabin, a work boat.

Others, a bit larger but with a large forward cabin, were used to run duck hunting parties.

Third Friday Speaker Series: Chris Cunningham « Bearings: The Blog of The Center for Wooden Boats

21terrapinpage

Also here, Tuckerton Seaport photo, there is a garvey with a forward cabin. Used to be lots of them around. I had to really, really hunt to find a photo.

Welcome to SJ Magazine - The Heart of Southern New Jersey

Then you can go to Parker Marine and there are some plans for sailing garveys and other interesting craft.

plans

Not to mention Phil Bolger. I ran into an AS-29 doing the great circle.

AS19 AS29 AS39

All leading to good options and I do like the AS-29 with a pilothouse, but how would you open the bow.....the Bolger Tri- with a birdwatcher style cabing has a false bow that detaches....

What do you think about the box keel under a more squared bow? Guess that would be like cutting off the first three feet of the 29 and taking it back further.

Wavewacker · 23-02-2012, 15:30

Hate to bump this

, but

I was being totally unfaithful being on another boating site and some suggested adapting a landing craft bow to an existing bow, above the water line. That would probably take the V berth away using it as a hold and walling up the interior aft of the berth.

What says you guys???? Guess it's easier than building the whole boat???

Jmahoney266 · 21-02-2018, 11:32

For Sale: One of a Kind Navy Landing Craft Conversion - Cruisers & Sailing Forums Take a look at this steel Landing craft conversion. 28'' Draft 50'x14'

Drew13440 · 21-02-2018, 12:01

Why not just get a true trawler and put a hoist on it that can handle the bike? There's probably a lot more bulk heads and concrete quays along the way that can handle the bike than they're are boat ramps that can accommodate an amphibious landing.

Cool idea, though.

CaptTom · 21-02-2018, 12:10

Just so y'all know...

The OP hasn't logged on since 06-06-2016. Hasn't posted since 30-06-2014, 09:54. This thread is from 2012.

I wonder if s/he ever did the loop with a bike?

john61ct · 21-02-2018, 16:42

Rig it so the cycle runs on rollers, provides the propulsion. Maybe side wheel? call 'er Proud Mary.

hellosailor · 22-02-2018, 11:55

Guys, the OP built his dream boat and took off six years ago.
It is unlikely he's still reading your replies.

**Lepke** · 23-02-2018, 22:11

I've driven WWII style landing craft and newer Mike boats. Boxy boats get pushed around more by the wind and waves. If you have a ramp, it needs to hinge above the waterline so you can have a pointed bow. Otherwise you need enough hp to push a tug.
The WWII boats were 36' (as I remember) and driven by a Detroit Diesel of about 200 hp. The later steel ones had two Detroit mains. They went almost the same speed empty as loaded. There are some later fiberglass ones. No faster, but easier to maintain.
If you're designing the boat, remember hull speed. The shorter the boat, the slower it travels unless it can plane.
You'd be better off and probably cheaper finding an original landing craft that still runs. Put a top over the well deck and you have your camper. Do the loop at 6 knots.