Launching boats from seasteads
July 1, 2008 at 8:07 pm #642
The method used by “free fall life boats” seems like a nice way to launch a boat from a seastead. They just fall into the water at an angle and then pop up. I put some videos of launches on the life rafts page. Seems like we might want to use this as a general (not just emergency) method to launch boats. Boats would have to be designed for this, and might also really be our life boats. To get the boats back up people use cranes.
We used to do something kind of like this in river kayaks. We would slide off 10 foot high rocks into the water with the nose down about like in the videos. I was always amazed at how gentle the landing was (though sufficiently worried about not getting the angle right to never try 20 foot rocks).July 1, 2008 at 9:03 pm #3406
Holy crap – 37,5 meters! I´m not sure I would want to do this if not in an emergency but as a lifeboat I´m all for it. I,m thinking some kind of winch system would be a little more relaxed way of docking and undocking your commuter/leisure boat. And a winch would let you use almost any boat on the market. I´m sure these lifeboats are quite expensive if they are to compete with normal boats on parameters like speed and usability, if that is even achieveble.July 1, 2008 at 10:15 pm #3407
Ya, that is rather high. With migration I don’t really expect to have to drop from 100 feet up. Dropping from 25 feet up in a 25 foot boat could really be very comfortable. You can almost spend as much time slowing down as speeding up, so the decelleration is not bad. Should be around 2 Gs.
Anyway, Its like having your own rollercoaster ride, my family would love it. Many amusement rides will have more Gs than this.
For out on the open ocean it seems like a boat like this that can handle being hit by a wave would be a good idea. And if you want a good lifeboat anyway (I would) then having it double as your way to get someplace is not really an extra cost. It might be a bit slower, but that is probably ok.
The new crss feed does not show initial posts on a topic. But you can click on a followup post and scroll up. I posted about using “free fall life boats” as regular boat launch method and had a link to videos.July 3, 2008 at 2:00 am #3412
This is getting a bit high:
Here is one from the view of the people inside:October 22, 2008 at 4:17 pm #4018
If you have a crane to winch the boat back up, why go through the extra expense of buying boats that can be launched like this? Just crane them down to the water.October 22, 2008 at 10:08 pm #4026
The “free fall life boats” can be launched in seconds. They end up away from the mother vessel and moving away. If you have rough weather and your mother ship is sinking, a crane and winch might not work (power may be out, ship may be leaning, waves may hit you before you are released, waves may push you into the mother ship before you get far enough away). So if you want to have a good lifeboat anyway, it could be your dingy as well. I don’t expect to drop from more than 20 feet, just love those videos. I really think me and my boys would enjoy the launch, and that is worth something to me.October 24, 2008 at 3:12 pm #4040
I grew up on an island only accessible by ferry, so I’ve spent many hours on decks a couple of stories up from the ocean, and I’ve never once seen an emergency craft of this kind. They were either inflatables, or crane-launched. this leads me to suspect that the crane winch technology is adequately fast in emergencies. I used to live aboard a small yacht built in the 40s, and it’s crane winch could be cranked manually if the power was out. I suspect modern systems have battery back-ups of some kind.
As a mater of lowering barriers to entry, I would recommend against such craft being the standard, however, on your own spar launch whatever way makes you happy!October 24, 2008 at 4:22 pm #4042
>As a mater of lowering barriers to entry, I would recommend against such craft being the standard,
>however, on your own spar launch whatever way makes you happy!
Right, whatever makes you happy. For me that is probably not even a spar design.
Some of my stuff is at http://wiki.seasteading.org/index.php/User:VincecateOctober 24, 2008 at 8:04 pm #4044
Is this what they mean when they talk about “mission creep”?
-Dude! You have like fifty lifeboats on your hundred person seastead!
-Those aren´t lifeboats. They´re recreational vehicles.October 25, 2008 at 6:20 am #4047
Freefalling from 100 feet should only be done as a last resort. It’s potentially lehtal if anything goes wrong, even for a boat fully-designed to do it. For example, if a seat harness isn’t properly fastened, a passenger could die.
The difference in energy from falling 3 meters to 30 meters is 10 times: Ep = mgh (potential energy is mass times gravitational force times height)October 25, 2008 at 12:08 pm #4049
I am only designing for 25 foot waves (plan is to migrate so as to avoid bad weather). So there is no need for dropping my dingy/liferaft more than 25 feet. I have done a free fall drop like this from around 10 feet in a kayak and it is surprisingly gentle. We used to slide off a rock into a river. The seats in the lifeboats are aimed backward and have full back support so you are well supported at impact. But it is probably worth checking that people have their seatbelts on before launching.
If a lifeboat was not strong enough to survive this kind of launch, I would not want to be in it during a storm (which I plan to avoid, but…). It really does not hit the water that hard. So it may not really add too much to the cost, compared to another hard lifeboat. Inflatibles are probably cheaper. I have not found prices yet. But with my wife and my kids on a new seastead design, I expect this is part of my budget.October 30, 2008 at 11:22 am #4096
Could we charge for this experience, make it an amusement ride?!October 30, 2008 at 4:59 pm #4105
How long does it last? 2 seconds? If you charge anything more than US$5 your customers will be angry. And charging 20 customers $5 each makes $100 per ride. Material fatigue will cost you a lot more in the long run.
Alternatively you could make that part of an survival trip. Lunching in bad weather (heavy rain, thunder, high waves) and after one or two days you land somewhere, pitch your tents, kill deers, etc.
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