Munson Catamaran Hull Trailer-able Houseboat

[Richard Woods]

To those who don’t know Fallguy is a very experienced motorboat man. Even if his Skoota is his first major boatbuilding project. So read what he says carefully

The reason I drew single outboards on my Skoota 20/24 is because of the oil sump problem that would happen with a folded transom hung outboard.

Fortunately in the last 5 years or so most manufacturers now have outboards that can be stored on either side

So I will be modifying the designs to allow for two transom mounted outboards. Although we have never had an engine fail in thousands of miles when we cruised our Skoota 20 any distance we carried a spare transom mounted outboard “just in case” it was never needed

Richard Woods

Www.sailingcatamarans.com

 

[fallguy]

By the way, I have rented houseboats about 6-8 weeks of my lifetime. The rental companies all ground them in winds over 15mph and this is on inland lakes.

 

[JYDOG]

Thanks for all of your valuable input everyone. My goal is to build a dual purpose trailer-able camper/boat that I can use on both land and water. I have a better understanding of what I am up against now. I don't think
a vessel in the 8.5' x 25' range would be very practical for making crossings so I would like to limit myself to coastal waters. It seems seaworthiness vs space and comfort are inversely proportional with the given size limitations.
What can I build or buy that would weigh around 5k lbs with trailer and have a similar interior of an airstream travel trailer and be able to handle coastal waters running from protected bay to bay or harbor? I am a novice in the
boating arena but here to learn. Most of my experience has been sailing Hobie 16's, force 5 etc.

 

[fallguy]

I am not sure the Skoota 24 would work for staying in on the hard and Richard is pretty busy now; so we may or may not hear from him.

Jacque Merten’s GT Cruiser 23 can be scaled up 10%; it would be economical to operate; fun to build in stitch n glue. Has two versions; a more houseboat version with a bit more cabin or a version better suited for going 30mph. Even the speedy version sleeps 4; 2 outside perhaps? Planing speeds require 70-90hp, but displacement speeds of 10 attainable with 25hp. Mertens also has an 8’ 9” wide 27’ version of the same boat with massive cabins. Plans are cheap; build support is great from forum members and designer.

Houseboat Designs | Cruiser Boat Plans | Bateau | Boat Plans For Amateurs https://bateau.com/proddetail.php?prod=GT23

 

[fallguy]

I said scaled; should have said lengthened.

 

[Richard Woods]

We are on land right now but still living on our Skoota 28, packing it up for the summer (early I know, but that's life) When on land we call it our "cabin", so we now have a kitchen not a galley. The Skoota 20/24 are similar to the Wizard/Sango sailing catamarans. We slept on our Wizard when on the trailer by the side of the road. Its quite high though in the cabin so a bit of effort to get up there

probably the Skoota 18 and Saylon are too small for what you want as I assume you will be spending several weeks on board rather than several days

Richard Woods of Woods Designs
www.sailingcatamarans.com

 

[fallguy]

The Skoota 24 is a different class of boat entirely from the GT. Staying in either boat on the hard would require ladders.

For me, deciding between the two would be simple. Do I wish to beach and do I wish to use the boat on the ocean.

Both can be beached, but the Skoota would be a preference for me.

For ocean use, I would prefer the Skoota for beam at sea and motion at anchor.

For inland use, I would prefer the GT for spacious cabin.

If I wanted to tempt crossings; both boats require care with weather; the GT more to windage. But the Skoota could be twin engined for redundancy; not sure if the GT could be adapted for twins; probably a JM question. But the Skoota wins easily for safety.

The other thing to consider is the movement on the water. The GT will certainly roll more.

The Skoota is a lot better boat for the ocean, but it also requires more build time.

And while both can be built by amateurs; neither would be a simple build for a first timer. The s&g easier.

Economically, the Skoota, built well, will retain her inputs value. The GT, perhaps, but less certainly.

For me, it all comes down to the mission statement. A mission statement needs to lead your search. As you can see your mission changed within this very thread.

Good luck.

 

[Touko Liimatainen]

I am just designing and my customer is building this kind of houseboat. This one has a full steel structure. It will be serving as a hotel room all round year in frozen lake in the middle of Finland.

 

[JYDOG]

So I decided instead of building a hull for 5-6k Id buy one and retrofit. I think this 96 Grumman 22' deckboat will make a good start for my trailer-able houseboat. I only paid 1600 for it and the trailer. Now I need some ideas on building the interior as light as possible.

 

[fallguy]

Do you understand how dangerous this proposition is? Looks like a nearly flat bottomed boat with a ton or better at 3’ higher cofg.

The rating plate has a gear max on it. Post it and see if anyone else wants to help you. Please keep in mind the horsepower rating will not be accurate if you modify the vessel.

I think it is a bad idea, so I can’t support it.

 

[JYDOG]

Fallguy you don't even have all the details and you are already to sink my idea.
This is for ICW travel only boat is rated for 130hp and 1155 cargo 1730 total (max).
I just want to cruise at 6 knots. 2-4 people at the most.
How do you get 2200 3' above cofg? You haven't even asked what materials it is being constructed with or how it will be powered.

 

[fallguy]

So the center of gravity increase is what I don’t like with the rated horspower.

If you figure 660 for passengers; you have 1070 left for the structure and engine, batteries, solar cells, stovetop, food, etc. Not much, but perhaps enough.

It is not something I am smart enough to say okay to..but as long as your hp wishes are reasoned; perhaps someone else can help.

Corecell 12mm is very light. Modify your design for windage; you don’t need full headroom in a salon sitting area; test the boat with some smaller four strokes.

I see you are not too crazy with a flybridge; that is good.

Personally, I would strip the loose parts out and weigh the boat and trailer and determine the boat weight at a certified scale; then strip out anything Grumman did that you can and weigh it again. You might pick up a few hundred more pounds.

 

[fallguy]

Comparing Cost and Weight of Flat Panels http://epoxyworks.com/index.php/comparing-cost-and-weight-of-flat-panels/

 

[JYDOG]

Comparing Cost and Weight of Flat Panels http://epoxyworks.com/index.php/comparing-cost-and-weight-of-flat-panels/

Thanks that is the helpful information I was looking for. How much HP do you think It will take to achieve 6-7 knots? 22' boat I would guess 19-20' at the water line. The boat has a small 8 degree v.

 

[fallguy]

Thanks that is the helpful information I was looking for. How much HP do you think It will take to achieve 6-7 knots? 22' boat I would guess 19-20' at the water line. The boat has a small 8 degree v.

No clue. I was thinking 20 horsepower might work, but you really might need more. The Tohatsu 4 stroke 20 is pretty light and you can get in for a couple grand.

But you really need to avoid that massive roof you proposed. The way to reduce windage and rooftop and weight is to put some angles into the walls. They won’t be too much bother because you have stuff on the walls. But then you need to waterproof them.

Take a picture of the inside of the boat. The gunwhales will be an interesting bit.

Maybe some other, wiser people with less liability concerns will help you. Sort of out of my league, but you better build it light or it’ll be dangerous.

You also might consider a forward cockpit or aft cockpit. Shrinking the living space will give you weight savings and allow outside seating.