Newbie

[daedong]

Five weeks ago l launched a houseboat that i built. It is now my intention to sell it as i will make a tidy profit. I intend to build another as soon as it is sold.
My question is what effect in regard to drag do you get with pontoons that are squared of at the back opossed to a Veed

[cyclops]

Probably little at a planing speed. Off plane, duct tape 2 cones on, do a good displacement speed -note mph- pull the duct tape off so the cones float safely away and note the speed change. House boat people do not run checks if they enjoy it.

[daedong]

It's just a tad big to duct tape to

[cyclops]

The Marine Engineers could tell with the length and O.D. and how much is submerged from a side view. And the speed. Right ?

[JonathanCole]

Originally Posted by daedong

Five weeks ago l launch a houseboat that i built. It is now my intention to sell it as i will make a tidy profit. I intend to build another as soon as it is sold.
My question is what effect in regard to drag is pontoons that are sqaured of at the back opssed to a Vee

How much you selling it for? What body of water is it in? How did you protect the pontoons against corrosion? How fast does it go?

How speed and efficiency relates to the shape of the stern depends alot on the speed you are travelling and the characteristics of the stern wake which you can search for on this forum. Eddies and vortices are sure to create an impediment to forward movement. but if you have sufficient horsepower you won't notice it much except on your fuel bill. We had a lot of discussion about slow motoring efficiency in a conversation that wrapped up recently. I am working on designing a solar powered housboat, so I am looking for a free ride and super high efficiency. We didn't talk much about the stern. But I am sure that there is more efficiency in a fine, angled stern than a box shaped stern.

[daedong]

JonathanCole

I live in South Australia by the River Murray

It has been valued at around $220,000au or about $175,000US.

Pontoons have been sprayed with epoxy tar paint and have 4 mag anoides on each pontoon.

It is powered by a 60 HP high thrust yamaha and it cruises at about 7mph

I am just looking for ways to reduce fuel bills on the next houseboat.

There are plenty of photos at the link below

[JonathanCole]

I checked out the pics on your web site. You are sure a can-do kind of guy. Your idea is really more a floating house than a boat. What is your fuel usage like per mile? On your next boat you could make it more efficient by making it

• lighter (resulting in less wetted hull surface which creates drag).
• finer (a more sharp angled bow and stern to reduce wavemaking) .
• fair (a more hydrodynamically shaped hull)

Clearly part of the charm of your design is simplicity of construction using really basic materials. If you refine your ideas incrementally by reducing weight wherever you can and reducing hydrodynamic drag and wavemaking, your houseboats will become more like boats which will have the added advantage of lower fuel use.

[daedong]

Fuel usage is about 1 litre to 1.3 kilometers (not sure on conversion)

[JonathanCole]

A little over three miles per gallon. Actually not that bad fuel economy for such a heavy vessel.

[daedong]

It weighs about 12 metric ton (incuding waste water)

[kmorin]

daedong, at the speeds and power to wt ratios you've listed, just make the after ends like the forward ends of the pontoons.

Since you're not going to plane this craft the after ends will do well as a "canoe". As you minimize the entry forward you can minimize the drag and eddies aft by making the pontoons symetrical about the amidships section.

certainly looks comfortable and spacious.
Cheers,
kmorin