Houseboat review

You are right. I missed the beam, which absolutely should be 8 ft.

 

Thank you for the advice. That's exactly what I did after the initial responses with similar advise to my original post. Post #12 has the new pics and it's an 8.333' beam catamaran / pontoon design now.

 

Another houseboat

I love houseboats. So I am designing an "oceanic houseboat trailerable".
It has a double box keel, to improve headroom on both sides, and to keep freeboard as low as possible. The box keel is quite thick because of the arrangements inside that need to be confortable, with walk around double bed, for example. Crew can move from port side to starboard thru the higher cabin.
Would it be self-righting? Please, I would appreciate some comments.LOA 9,99 meters, Beam 2,3 meters

 

I am sorry Ricardo, but if you design it you shoudl know how to caculate the stability, and other parameters.
If you don't know take your project, and go discuss it, as a design base, with a naval architect, so he can design exactly what you want. And you will be safe and happy.
Designing a boat is very far from playing with a pen or computer. BUT it is always good to come with a very strong idea so the NA is guided at the start.
So you have your dream on paper, it is a very good start. Now take it to a NA.
I wish you the best of luck
Daniel

 

Dear Daniel,
Thanks for your comment. I bought some plans of very serious sailboats, years ago. As the years passed I decided about other priorities, including a different type of boat (that could even carry a dinghy sailboat). So I have access to many structure drawings and manuals. I studied a lot about boatbuilding, boat design, and I have a book collection about boat bulding and boat design. I like spartan designs like Philip Bolger, Jim Michalak, and Michael Storer. I do need to make calculations, and even hire a NA to help and legalize my project, much later. I am not playing with a computer... This thread is about houseboats, that are normally not intented for hi performance, and the forum is for design discussions. Sorry if my post seemed to be naive. We could reply "Hire a NA" to every single post, couldn´t we? I would like, please, a comment from someone interested in looking at the image I sent... Thanks, Ricardo
PS: I forgot to add that I sail, and used to own a small sailboat sold last year, worked with boat charter, and I am a serious person, married, and...

 

Of course Ricardo you are right. we can't say to everybody: go see a NA. It will be rather stupid.
What I try to say is: your job is important, since as the owner you are the one who knows what you want.
So coming with a strong idea, it's a dream for a NA, if the idea is not completely off of course, since he can start immediately his job on the right path.
I had a client like that: he came with his schooner already all decided, and some sketches. I was able to design the boat in no time, the building was easy, and the sailing great.

Go around in your country to check the best designer for your project, try to find one who understand house boat. Mostly the history and vintage houseboat. I love house boat I am building one for myself and my wife, and one for a customer. I find them attractive and so comfortable.
But please Ricardo, don't make me wrong: I am not fishing for business. I just share what we have in common.
Let know the progress, you are part of a very elitist group of people: The house boat fans
By the way if you built yourself and for your own use you don't have to pass the stringent CE rules. You can't sell the boat for a period of 5 years. So don't bother with regulation if you built yourself.
Daniel

 

Hi Ricardo

First it is good that you are prepared to have a go and it is good that you have ideas that you are prepared to display. It is much better to have some pictures than rely on text as far as good feedback is concerned.

Firstly I think it is fair to say your design would not do too well in an Ocean.

I can see that the bottom is flat in the middle. As the boat goes forwards into waves it will slam really really badly. I am pretty sure this is where the boat will break. (slamming forces will be immense!)

As to stability, it could be made self righting if you had enough ballast in the keels. But you will need ballast, my guess more than a tonne.

The sides are high and vertical, the forces involved when waves impact on these will be large.

The stern is wide and vertical, in a following sea waves will pound that and make the boat hard to control, also teh stresses on the transom when a wave breaks against it will be huge. I can see that you have tried to get as much interior space inside as possible to assist in comfort.

Your width is set at 2.3m, but legal trailering widht is 2.5m in Australia, a fraction higher in US, so going a bit wider is probably prudent.

I must say that although it is not suited for an Ocean, it does kind of grow on you. I like the small deckhouse with 360 degree vision.

I would be tempted to fair teh lines of the keels into the shape of the topsides at teh bow. That would mean extending the outriggers forward a little at the bow.

With a little more shaping, 20cm more beam, adding some Vee section at the bow to reduce slamming it would make a nice houseboat for protected waters. However you could not take it into the ocean, sorry. (Technically if you had ballast and made it very very strong yes you could take it into the sea, but do not think it prudent)

Often designers try to minimise wetted surface area. Your design has heaps, particularly as the 'floor' is just below the waterline.

To get better feedback it would be nice to know your approx budget, timeframe, your location, and where u want to go.

Here is something is similar size range.
http://www.bateau.com/proddetail.php?prod=GT27
You can see that this one is still only recommended for protected waters, despite having a better hullshape for waves.

If you wait a few days, I have been working on something similar that may interest. It is not a design, but rather lines and diagrams. From those you would then need to pay a NA to do the detailed designs for you.

What is the plan? to do lots of small trips in protected waters, and then a few years later to motor cruise across an ocean. Chances are you may need two different boats. A houseboat/sampan for protected waters is lot easier to design and can get away with being 'boxy'

here is somehting for protected waters
http://joliboat.blogspot.com/2009_03_01_archive.html

Note that your 'projected' boat is both higher and narrower, giving more concerns as regards to stability.

good luck

 

Dear Peter and Daniel, thanks for your comments! I will consider and study them carefully. I think my project is quite ambitious, not only because of the all-purpose idea (ocean and river)... The narrow beam is also for channel cruising, and low power requirements, and to be honest the 2,3m beam is to make it fit in a container, and the project hard legalization is to sell units around the world (before the 5 years wait) (sounds insane, I admit). I am in Portugal, Porto, there is the great Douro River for a 200 km travelling, thru beautiful wine fields, and that is it. I need a boat with coastal capability to visit other places along the european coast (that would be navegation category 3, and should stand swells up to 2 meters high). I need a cheap getaway houseboat (get-very-away), and the plan is to spend more time stopped than moving. There are many marinas along the european cost and it is possible to make very short legs if necessary. I am not sure about the twin box keel for coastal navigation, as it would require a lot of ballast, and the freeboard is hight as you said... The other option would be a more traditional single box keel, with a full standing headroom in the corridor, and lower freeboard.

 

I just undertood your suggestions Peter, about extending the box keel forward (or the outriggers, as you called) to the bow, and faring with the top sides. I did that in the first drawing, but the keels are already too large, and I wanted to improve maneuverability, making it shorter forward and aft. I also do not want the keels to float (as outriggers). The great wetted surface is to improve stability, and create standing headroom.

 

hi Ricardo

Here is my suggestion, an idea I have been working on for a few weeks
It may fit your bill

http://www.tacking-outrigger.com/b_boat.html

As to your desire to fit into a container and thus the 2.3m beam. Perhaps you could try the design as I have shown, and make it narrower, and compensate with larger sponsons. I did not draw this for yourself, it is something that has been in the back of my mind for awhile now. Just thought now was a good time to make it available

In the end it is up to you. It is pudent to ask for feed-back, but in the end no one is going to stop you from having a go.

If anyone else would like to comment, please feel free to express your opinions. I have a full time job in the paint industry, and doing boat sketches is just a hobby, so as an amateur I may well be getting many things wrong
good luck
n peter evans

 

hi Ricardo

getting back to your design

I think that having a central box keel would be far superior to having 2 smaller box keels on the side. The central box keel could be extended right to the bow stem to give a deep narrow entry that will cut through waves.

Your design as shown with the central floor below the waterline, this will not be any more stable or any less stable than the floor above the waterline. It is true that having the floor below the WL does allow for greater standing headroom and will lower the center of gravity, but having air or water below the 'tunnel' will make no difference to stability by itself.

Having a 2.3m wide vessel with a central box keel would work quite well for shetered areas and for canal cruising. Then if going offshore, spend a few hours bolting on sponsons to give more righting moment at high angles of heel. I think that could be a real nice design.

 

Dear Peter! The bolted sponson idea was very good, thanks. I found a photo of a sponson in wikipedia. I like passive systems Sometimes I think about a boat that can be enlarged, or upgraded for other purposes, and the sponson would be a cool solution for a "modular" boat

 

Not that sponsons can't have a good justification, but I am personally highly suspicious of any boat that needs them for its primary purpose. Personally I see them as a solution to a problem that should have been solved during the initial design phase. The picture you posted for instance is of the MS Moby Otta, whose sponsons were added due to more stringent safety concerns, and only after she capsized while in port.

Note that they can and sometimes make sence when boats are redisigned for new applications.

 

hi

It is just my 2 cents worth, but I see them as a legitimate way of increasing stability at high angles of heel, whilst still retaining the 2.5m trailerable width whcih is desirable. If the sponsons were welded on, and the craft viewed as a whole, it may appear presentable. Additionally sponsons could be so shaped, as to be a continuation of teh chine, as to appear almost invisible.

My gut feeling is that a craft with 2.5m width and 2.1m of height to accommodate standing headroom, a double bottom and cabin roof beams will have some problems with stability in a big sea. Increasing widht from 8ft 3 up to 10ft 3 could be seen as a good thing.

In teh end it is all about points of view. You have your opinion, I have mine. If it works in practice and then everyone is happy. I can see that it is not an ideal method, but I feel it is preferable to having a narrower beam.

I have had thougths of building boats and sending them away in containers, trouble is that small yachts and such usually have a wider beam than the container is wide. One option I thought if was to put the hull into the container on it's side, (containers are higher than they are wide) and sell the boat as a kit where all the purchaser has to do is attach the keel, and then bond the cabin top to the remainder of the hull. I think this could work for small yachts up to about 22ft of lenght.

good idea?

 

Thanks Stumbler, good point and clarification about the photo. I think if the sponson is designed from the start as part of the boat it can look good, and have added funcionalities.

Peter, I just saw your drawing, nice sea-van
I think your sponsons are not necessary because your boat is a lot lower. Also the sponsons seem to be too discreet, and would start working too late. I would put it lower and by the WL... (don´t know...)

The container door is 2,28 h by 2,33 wide, so the container is higher only from outside, not its doors. My design was made as you said, with a removable cabin top to fit the hull in container. I also thought about a design to be transported on its side, not in containers, but on the road! with trailers, or big truck, that way it can have a nice beam...