"Life Tender" as an alternative to life raft

Discussion in 'Boat Design' started by Owly, Jun 20, 2018.

  1. sailhand
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    sailhand Junior Member

    Hi guys just to bring the thread back to what I see as the main focus, and that is a non inflatable multi role tender/liferaft design. I think there will always be horror stories with any type of vessel. Even the supposedly unsinkable titanic sunk and the liferafts were not inflatable. Many were damaged many were not, and I believe the seas were relatively calm at the time. I think the main intent here is to look at the best design for a solid multi role liferaft and to that end I for one see this as one of the best forums to discuss this concept. It is also probably about time we had a major rethink of these designs, such as the Portland pudgy, given the advances in building materials and tequniques not to mention rescue equipment epirb rescue beacons etc etc. The Portland pudgy addresses many of the problems inherent in liferaft design, but not all and I think some could be done better. In colder climates the deflation of a liferaft could be a death sentence within a very short time. However in large stormy seas being near a small rigid dinghy is fraught with danger also. If you end up beside it in the water you could be injured by it as well. So many variables and compromises like everything else about boats. If you'e ever been hit in the head by an errant surfboard you may question the hard dinghy concept, maybe a combination of the two, or maybe something completely new like something in Eva foam like a giant crocs shoe that can' deflate but also would be softer if hit by it. If being rolled multiple times in large seas the likelihood of being injured in a hard dinghy is reasonably high. Unless you were strapped in fairly tight. Then I suppose self righting and adequate ventilation/air supply would be required. What about a central rotating pod that remains upright whilst the rest of the dinghy pivots around it or a sphere that is composed of 4 or more shells that can be rearranged to form a dinghy for tender use when in port. Floating around in a sphere would not be very practical in calmer weather. Mr efficiency you are right about the trawlers and there dinghys on the roof. Invariably many of these disasters are a result of hookups whilst trawling and the vessels are sunk in seconds not minutes. I know of three such incidents with nets fouling on bottom structure of some sort and dragging the vessels under. It is also very common with smaller crews to have the skipper out the back on the sorting tray and the helm unattended. Reading marine incident reports is invaluable to our knowledge on this subject and they are readily available online. There was a great documentary a while back on the monohull sailing vessel that lost its keel off the northern nsw coast. If it wasn' bad enough that only two survived the initial incident they were subsequently run over by a large ship and after bouncing along under the hull emerged unscathed out the transom, missing the propellors and rudders etc. They were in the water in life jackets and eventually rescued. I am not sure what happened to there liferaft it may have got trapped under the hull or just failed to deploy as you infer happens with the trawlers and there tinnies. The last thing I would want to carry as a survival vessel is an oversized beer can with bugger all bouyancy and sharp corners edges etc all over it. But better that than nothing.
     
  2. Boat Design Net Moderator
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    Boat Design Net Moderator Moderator

    In an effort to try and turn the thread in a more productive direction, the thread title is being changed from the original "Death Rafts, a false sense of security" to "Life Tender as an alternative to life raft".
    This seems to be more consistent with what the OP said in a subsequent post
     
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  3. Angélique
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    Angélique aka Angel (only by name)

    I'll escape to the boat jokes thread . . :eek:
    only for a while ;)
     
  4. Angélique
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    Angélique aka Angel (only by name)

    No problem to post an example of that as well, for peace of mind, and peace on the thread . . :)

     
  5. Angélique
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    Angélique aka Angel (only by name)

    The below pics come from some currently running sales ads . . .

    I don't see a hydrostatic release unit (HRU) on the life raft cradle, which made me think it might be a good idea to have a HRU on the dinghy holds as well, when the dinghy has permanent built in flotation...

    Friendship 35 (spare link) from and in the Netherlands

    [​IMG]

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    Lidgard 41 (spare link) from NZ currently in Greece

    [​IMG]
    is the same dinghy
    [​IMG]
     
    Last edited: Jun 26, 2018
  6. Angélique
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    Angélique aka Angel (only by name)

    Re: posts #17 & 18
    Split off thread: Hidden airbags to keep a yacht afloat in case of an emergency, like in the VDS example case.
     
  7. Angélique
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    Angélique aka Angel (only by name)

    This might be an interesting dinghy for this thread, the Walker Bay RID (Rigid Inflatable Dinghy), which is of the same concept as the before mentioned Duo by forum member Richard Woods.

    - Walker Bay 8: L 2.50 m (8' 2") B 1.32 m (4' 4") - 32 kg (71 lbs)RID incl. tube: L 2.75 m (9') B 1.72 m (5' 8") - 40 kg (89 lbs) = below shown stored on the scoop.

    - Walker Bay 10: L 2.95 m (9' 8") B 1.45 m (4' 9") - 57 kg (123 lbs)RID incl. tube: L 3.1 m (10' 2") B 1.83 m (6') - 68 kg (146 lbs) = shown in the below video.


    Saw forum member Yves-Marie de Tanton has created an interesting storage place for a fully inflated Walker Bay RID on the scoop of his 42' Blue Water Ship, this boat also carries an liferaft, which is stored in a box that doubles as the cockpit table.

    Note the dinghy upside down, with the built-in mounting eyelets slanted strapped against the angled watertight aft bulkhead, partly under the aft deck overhang, which contains the helmsman seat.

    link 1link 2

    [​IMG]

    [​IMG]
     
    Last edited: Apr 11, 2019
    bajansailor likes this.
  8. Squidly-Diddly
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    Squidly-Diddly Senior Member

    how about a hybrid RIB, where the ridged part is solid flotation and has extended raised sides, and the inflatable tubes are supported by flexible struts about every 2ft, so even if the tube goes flat the struts will keep it up and functional.

    Or one of these, but with a "hybrid RIB" you'd still have a planing hull.WALKER BAY PVC Tube Kit for Walker Bay 10 | West Marine https://www.westmarine.com/buy/walker-bay--pvc-tube-kit-for-walker-bay-10--5362868?mrkgcl=481&mrkgadid=3076578726&cm_mmc=PS-_-Google-_-GSC>NonB>Vendors-_-5362868&product_id=5362868&adpos=1o2&creative=108421556404&device=c&matchtype=&network=g&gclid=EAIaIQobChMIsuuokpvk4QIVEarsCh2kWQRBEAQYAiABEgKUCfD_BwE
     
  9. BlueBell
    Joined: May 2017
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    BlueBell Ahhhhh...

    If it's floating and it's tied to the boat I'm sinking on,
    you can call it whatever you like, but it's just become...
    A LIFERAFT! (Duh)

    Tenders really are handy, especially when the mothership sinks!

    Do you stow a knife next to the painter on your dinghy?

    Proper liferafts really are superior however.
    And expensive, just like Mustang inflatables.
    (I see a theme here...)
     
  10. Angélique
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    Angélique aka Angel (only by name)

    Might want to tie it down with an HRU (hydrostatic release unit), like on any proper life raft installation.
     
  11. BlueBell
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    BlueBell Ahhhhh...

    You have confused a dinghy with a certified life-raft.
    When I tow a dinghy it doubles as a life raft and keep a knife stored in the bow for emergency cut-away from the mother-ship.
     

  12. Angélique
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    Angélique aka Angel (only by name)

    What did confuse me was that I didn't realise that by tender you've meant actually towed, the HRU suggestion was for when a "life dinghy" with positive flotation is stowed on deck. For sure you've posted a good idea to store a grab knife on a towed tender...

    Which makes me wonder about life saving capabilities of tenders that are stored in inboard garages onboard super yachts . . .

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]
     
    Last edited: Apr 23, 2019 at 8:52 PM
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