Are there displacement hull ships with extendable hulls out there?

Question

I am currently developing a displacement hull boat whose hull length extends to 500% of its mooring length when wanted, to increase hull speed and speed capability.

Is anyone else doing this?

I haven't found anything so far, and would be glad to find something, as this is a research project, and it would help me to find any hint at all of boats or ships which are extendable.

Thanks.

Answer 1

I have been around boats all my life and have never seen or herd of anything like that.

Answer 2

already answered this i think in your other question. but i think your missing a point here that you need to concider. in principle, the idea isa  goodone, but your changing the hull length, but yet, on its own, would make no difference.

as said before. yes, generally speaking, a longer hull, will have a higher hull speed. but, unless youi change the engine too, all you are doing is placing yet more load onto the engine, thus, actually, reducing the boats speed. max hull speed is used to determin the maximum potential speed of a specific hull. although there are many factors involved, the length is a basic rule.  however, that is its maximum, the speed at which, no amount of extra power will increase it beyond that point (hence planning hulls) so in theory, your boat will be capable of a larger speed. but, if everything else remains constant, especially power, then as i said before, its like taking your family car and adding a trailer to it. the engine remains the same, and thus, the speed is reduced, due tot he larger load.

you are also going to have major design issues with structural integrety of a design like this. especially if you use it in water where there is motion. because, typically a hull has a keel and stringers, designed to spread the load along its length. by adding onto that length, you will have to have a break in these stringers. that becomes a weak point, and if its not the hinged area, it will be, and you will end up 'breaking its back' so to speak.

i can see a potential in this. allowing large ships to dock at smaler berths. and with the right design and some major engineering, you could possible devlope a system that provided enough structure to cope. but unless you crank up the horse power, your going to go slower. but as a design idea, not worrying about specific boat. yes, its a very interesting idea and i could see some applications for it, but the strength is going to be the biggest challange.

Answer 3

Nothing commercial, anyhow. Stress modulus issues, i would think.