survival boat

Hi Taniwha

I agree with what Bataan says, a traditional ships boat shape is best. What can you add today but not then? Maybe inbuilt buoyancy compartment, mabye lots of strong lockers for water and food.

A simple unstayed boomless rig would be best, probably better range and performace that electric. Electric drive might have the advantage of providiing inbuilt ballast down low, to keep the boat more steady

What sort of means do you have for keeping breaking waves out, what sort of canvas cover. In terms of layout, the bow would be covered with canvas for 2 people laying down, then afterwards, you can have a couple people sitting next to each other.

6ft lenght for 2 people laying down, 4ft for 2 people sitting next to each other. 1.5ft at the bow. 0.5ft buoyancy compartment at the stern, total 12ft

Note that if you have a pram bow, you can get more per given lenght. squeeze a bit more boat in. Dont forget a sea-anchor to keep the bow into the waves. The thing about rafts is that they have a cover to keep the wind out, exposure can get to you before you succumb to thirst or starvation

So, for me a 12ft pram works best, between 5 and 6 feet of beam

 

Not survivable, IMO. Prepare for the worst and expect to be rolled. The issue of exposure and hypothermia at higher latitudes, and the closed in inflatable raft is the best option. And only the best of those too.

 

Cold water immersion suits + enclosed EPIRB would be the simplest. Otherwise a packed self inflating survival raft including EPIRB for an extended survival scenario. Don't see how any on board propulsion power would be of much use with all the random currents, waves, wind. This has been done already, and PROVEN to work. When these haven't worked, no other design would have made much difference, IMHO.

Porta

 

A life raft is instantaneous, all weather and portable. You simply cant sail without one. Nothing wrong will improving your tender to make it a life raft support craft. I would suggest fitting a robust waterproof cover to a self bailing, when empty of passengers, tender. .

 

hi

I do agree with you, a liferaft is best, but he seems set on a tender,

Can a 12ft tender have a watertight cabin forward, or can all the topsides be made watertight with canvas. Trouble is that cost to do so would be more than a liferaft. It could be done, but it would be very very difficult, I suppose you could have a canvas covering the entire boat, with one small hole, then use a bridge pole of some sort to give more space,, possible, but not easy

Seriously, with Epirbs, survival suits, would not a liferaft be better than a tender

 

No there is no matter of one better as the other. I have been working for National Sea Rescue for 8 years now and one thing I learned is that no 2 rescues are the same. Mandatory we must have an Epirb and a liferaft (+flares, etc..of course). When I say I prefer a dinghy to a liferaft I actually mean that they are situation where you do not have to leave the ship because of the perfect storm but because of leaks, fire or whatsoever. And IF the conditions are such that I can sail to land and I am in a country where the activation of the Epirb would be of no much help (remember I live in Africa) THEN my choice might be to take the dinghy and in that situation I would want my dinghy to have a lot of buoyancy, storage space for food and water and a mean to sail. The Torqeedo 1003 with integrated battery connected to a solar panel would give me 1kn continuously during day light, not much but if there is really no wind then every little bit helps. Maybe I could have an emergency watermaker even 1l a day would help. I could have battery operated LED built in the boat sending SOS code, I could have place for a slightly bigger VHF battery, a place to put my Ipod with charts/GPS etc..Why are dinghy manufacturers not taking these things into consideration?

 

I assume you will be sailing a small craft....10 to 15 meters ? Then you will find it difficult to store a suitable size rescue craft on deck .

Then you will find it difficult to deploy this tender.

I sail an 80 ft yacht and we strip the tender off deck for ocean passages. to vulnerable to wave wash...to space intrusive...and to expensive to loose.

If time permitted in an emergency I would electric pump inflate the tender and find a use for it.

 

www.passagemaker.co.za 48ft Tad Roberts Passagemakerlite with ample space on aft deck and boom to launch the tender.

 

Never leave without a liferaft . If you would like to sea launch a ruggedized tender as an additional safety vessel containing extra " grab Bag" drinking water , food and suplies Go for it .

Remember, its Not easy to use a boom crane at sea . A method to push your tender over the stern attached with a long painter would be good. Perhaps self launch by first deploying a sea anchor that drags the tender free of its cradle and over the stern.

 

Dinghys have poor buoyancy, storage space, and sailing is an afterthought (no keel, permanent mast, etc.) COMPARED to an equivalent life raft. There have been hand held floating SOS code beacons in the past which could be fastened to any boat/vehicle/building or simply held while floating in an immersion suit. Thrust per pound of motor/panel/battery weight is unfavorable for electrics compared to sail/kite/gas motor.. Why is it impossible to sail/row a life raft to land, unless the currents push you away in Africa? What about using a jet ski that can be lowered off the back and tow the others on skis or a floating device that planes? That would eliminate a lot of redundant survival gear and long term misery, while staying in the same weight range. Dinghy manufacturers will not produce what you propose because there is no demand for such a thing and a lot of better alternatives..

Hope this helps.

Porta

 

well at least I found one guy that agrees with me:
http://logofdelviento.blogspot.com/2010/11/life-raft-or-lifeboat.html

 

Is the sail rig warranted to stay intact when the whole deal rolls or pitches over ? Back to being a raft if not. Assuming it rights itself.

 

I like Battan's big pram. A pram will have the greatest volume and stability in a given length. Fit an inflatable or foam collar around three sides.

Shallow vee bottom so the bilge water has somewhere to go, increase deadrise forward. Fillet and tape ply construction with positive buoyancy built in.

A Bolger Birdwatcher type cabin would be workable, with zippered fabric center roof section. Unstayed mast with boomless sail, use an oar as a sprit boom.

 

Don't you think it is a bit too big Tad?

 

A true life boat is double ended. A stern is not needed and swamps when towed . A double ended pram might work. Your problem is that your boat is so small .