What floats your boat.

Here we have a thinking man/person with an open mind, and inventive.

 

But having no application to your customer's boat, yes ?

 

About the only application to a low draft speed boat that I can think of (because you don't want a lot of windage) would be with a RIB where the inflated pontoons were filled with lighter than air gasses. I would imagine that the difference would be small for the expense incurred (though that need not be prohibitive given the already comparable nature of the pontoon). Of course while most seem unaware of it we seem to be running out of helium so that leaves mainly hydrogen -- "Hindentanic" for a yacht name? -- or regular air heated by engine exhaust or some such.

Aside: I wonder what Bolger would have done with a RIB? A State series boat called either California or Texas (either in honor of all the hot air)?

NOTE: native Texan.

 

As few posters are committed to making progress to try and achieve the needs of our customer and are getting unruly and not game to give a sensible opinion. it would be a good idea to do what the customer thought was the best and most practical bottom shape for his boat, a v bottom with 6 inch dead-rise and move on.

The customer has asked for a boat that is easy to trailer, that is easy to launch and retrieve and launched without a lot of work.
He wants to back down to the water and not immerse the hubs of the trailer in the water ( to save maintenance of bearings) just remove a restraining strap across the back of the boat and grab the painter and gently push the boat from the trailer into very shallow water.
He also wants to have the trailer usable for other purposes and wants a flat deck 6 feet long by 4 feet wide.
As there is little is little storage place for other trailers he needs to easily put the boat on the floor of the shelter so he can use the trailer.

 

The air in the RIB tubes effectively weighs, well, nothing worth calculating. You might save a kilogram or two, not worth it.

 

That would be no fun in the summer.

 

Well, 260 posts and it's right back at the start, but now it's a different priority, a new project. The main venture capitalist/chief financier of the endeavor doesn't have enough money for a small utility trailer. He has to put the boat on the floor because there is no room for a small utility trailer. Think about that. He has to put the boat on the floor because there is no room for a small utility trailer.

This is going to be a worldwide company with international patents, offering state of the art hull construction and revolutionary drive mechanisms.

I guess I'll just keep watching and see what happens.

 

Costa Concordia was re-floated and stabilized with extra buoyancy because it was in bad shape.

 

You are welcome SamSam.
Right back at the start same customer requirements as in post#6.
Easy to trailer. We will probably get and Engineer to build it to our specs.
A World boat and safer for our tourists who are killing many Kiwi`s by driving on the wrong side of the road,they do a better job than terrorists so far.

 

Some people do not have a lot of stamina or helpful friends on boating forums.
At least he tried and probably learned a thing or two.

 

Like I said, small for the expense incurred.

Kinda like throwing extra HP on a boat already moving at her limits.

Mind you, it's a popular option among the money to burn crowd.

 

You could add extra foam flotation into every available space in the boat so it would float higher and have less draft.

Assuming killing Kiwis is a bad thing, you could ban tourists from operating boats on the road. Or, if the object is to make it safer for tourists, seat belts and airbags would do it. Airbags could double as flotation for even less draft.

 

Looks like you need a refresh in the ABC of buoyancy, SamSam.
That's not how foam flotation works. If you fill the void space inside the boat with foam, you are just adding weight (foam's density is 20-40 kg/m3). Hence, you don't decrease the draft, you increase it.
The flotation foam starts to work in case the boat gets flooded with water. Until then, it's just an added weight.

 

Tom; what the customer wants is not what he needs if it is to satisfy the requirements that he has set forth.

Minimum draft: No dead rise! It will be flat bottomed whether his perception of correctness is correct or not. It is not

Easy to load and unload from the trailer: The boat will be as light in weight as is reasonable. It will have a flat bottom. Flattiess are distinctly easier to load and unload, that sort of boat will sit lower on the trailer than a vee bottomed boat, thus it is nearer the water when loading or unloading.

Trailer; A flat piece of ply or other material is fine. The boat will live there nicely. The trailer can be used for utility purposes with its flat deck. The trailer will not need chocks or bunks to hold a vee bottom in its place, so there is no obstructions when the trailer is used for utility purposes. My trailer has that exact layout. The flat deck of the trailer has carpet across its top surface. That makes the boat easy to slide on and off the trailer.

Here is a crude picture of my 16 foot flattie on just such a trailer. The trailer does not even have a winch. It does not need one. The boat unloads, as you say, with a gentle push off the back of the trailer. Loading/unloading without getting the axle and bearings wet is possible on some ramps but not all of them. Depends on the angle of the ramp. I do not see routine bearing maintenance as a serious liability, so I do not hesitate to let them get wet. Actually they do not endure much if any damage because the bearing seals do what they are intended to do.

The boat in the picture, with me, the tiny motor, and all the contents weighs 325 pounds all up. It goes well with a little 2.3 HP Mercury outboard. (I think it is probably a re-branded Tohatsu) It can and does, plane with that wee little motor. Twelve MPH when the motor is revved up. If the boat had a vee bottom it would not do that. At idle throttle settings the boat moves at about 4 MPH.

 

Hasn't this whole thread been about a misunderstanding of buoyancy?

As has been pointed out above this will increase draft, not decrease it.