Houseboat review

[Stumble]

Just to clarify my previous post,

In this case I would agree that the sponsons might be the best design option. Not because of the desirability of sponsons, but because of an artificial limintation of width in the design spec. So here unlike in a more traditional design they could be an interesting option. However given the desirability for more stability in a given length I would just look at a designed collapsing tri-marane. Same skinny hull, same broken down width, much much more stability with the outriggers than with sponsons.

[Ricardo Ramalho]

Hey my friends, check "the beast" The sponsons can be stowed in the front deck grooves. Plus, they could be assembled and become a small catamaran independently. (I could make them outriggers as a trimaran, but did not draw that yet) (I still need to do some shines to improve shape bellow WL). Although it was not my intention it is beginning to look fast isn´t it? I am afraid the water would go over the sponson... (Another option would be making the sponsons longer, so they would meet the bow curve... that would require the bow to be totatlly re-designed too...).

Sponsons or not, this is never a coastal going vessel! Let alone ocean going. What you have drawn here is for VERY sheltered waters only! The Duoro was the right place.

[Ricardo Ramalho]

you are hurting my feelings... (just kidding), "I will be back"

[peterAustralia]

hi Ricardo

Well your drawings are amusing, I thought the one on the right was what happens when you add too much power, though I realise it is just done for effect. I think you have promise as a graphic artist.

Seriously, this is a better than the previous attempt, but still has a way to go. The main problem remains unresolved, stability.

I do like the box keel, looks as though it is in proportion. adding some chines would sink the boat a little, and increase its ability to roll independently of the shape of the water surface.

A little more about stability. There is initial stability and final stability. Your boat has initial stability, if you take it on smooth waters the wide flat bottom will give a steady and comfortable passage, and it will go well. The trouble is that you are still limited to 2.3m beam. When you go down to your local marina and see the power cruisers, what is there beam? Next to where I live there is a ferry for the river in the same size range, I would estimate its beam at 10ft or perhaps more. Find me an ocean going motor cruiser that is 2.3m wide.

What I am trying to get at, is ask yourself what happens should the boat get hit by a big wave. The boat heels a large angle, then what happens, you start to get less and less stability the further you heel. What you need is a way to get more stability at higher angels of heel.

Thus the sponsons need to be larger and be higher up.

I would recommend you do a little reading on stability curves and also metacentric height. If I were to put your design into the software I use, I can calculate center of buoyancy. You could also estimate center of mass from the materials in your craft. Now a more sophisticated software package could tell you what the metaceter is.

You will need ballast and in the keel, otherwise you are stuffed.

One thing I was getting at with boats in containers is that there is a container called a HiCube that is taller. Boat can go on its side and have a higher beam.

With the sponsons where you have them, a big wave will immediately immerse one of the sponsons, after that happens you actually have less stability. Thus you have more initial stability and less final stability. Get hit by a too big a wave and over you go.

I would like to see the stern narrowed a bit. Wide sterns provide lift for fast power boats, but for displacement speeds motor cruisers, almost every craft will taper towards the stern. You also have no rocker, a little rocker would be prudent.

in other words, you need to make you boat, more boat like!!!!


An aside, the trimaran setup you mentioned, yes that would work, it is a different craft with high stresses, but it is an alternative. There are a few ocean going fast trimaran ocean cruisers about.