"Life Tender" as an alternative to life raft

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

  1. sailhand
    Joined: Jan 2017
    Posts: 97
    Likes: 19, Points: 8, Legacy Rep: 29
    Location: australia

    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
    Joined: Feb 2010
    Posts: 488
    Likes: 87, Points: 28, Legacy Rep: 1004
    Location: www.boatdesign.net

    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
     
    bajansailor likes this.
  3. Angélique
    Joined: Feb 2009
    Posts: 3,005
    Likes: 317, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    Angélique aka Angel (only by name)

    I'll escape to the boat jokes thread . . :eek:
    only for a while ;)
     
  4. Angélique
    Joined: Feb 2009
    Posts: 3,005
    Likes: 317, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    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
    Joined: Feb 2009
    Posts: 3,005
    Likes: 317, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    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]

    [​IMG]

    Lidgard 41 (spare link) from NZ currently in Greece

    [​IMG]
    is the same dinghy
    [​IMG]
     
    Last edited: Jun 26, 2018
  6. Angélique
    Joined: Feb 2009
    Posts: 3,005
    Likes: 317, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    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
    Joined: Feb 2009
    Posts: 3,005
    Likes: 317, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    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
    Joined: Sep 2007
    Posts: 1,446
    Likes: 52, Points: 48, Legacy Rep: 304
    Location: SF bay

    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
    Posts: 808
    Likes: 88, Points: 28
    Location: Victoria BC Canada

    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
    Joined: Feb 2009
    Posts: 3,005
    Likes: 317, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    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
    Joined: May 2017
    Posts: 808
    Likes: 88, Points: 28
    Location: Victoria BC Canada

    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
    Joined: Feb 2009
    Posts: 3,005
    Likes: 317, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    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
  13. fallguy
    Joined: Dec 2016
    Posts: 2,091
    Likes: 131, Points: 63, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I read this thread (post renaming) a few times and I find it rather humorous that it is either one or the other. Rather than either or, redundancy seems to be the order of the day and we learned it long ago, or at least I did reading the Dougal Robertson story. Like the fellow with the 44' bluewater catamaran, fire is probably the single largest threat to my boat. And more so since it is gas powered. So, I have been trying to come up with a nice dinghy that could also be used for a temp vessel in case of fire. And, of course, I shared this notion with a forum, and proceeded down Polemics Avenue with some of the guys on that forum about how I need to have a liferaft and am being foolish thinking a dinghy could save my life.

    And by reading this thread, I am realizing a knife hidden in the dinghy to cut it free from lashing is a super idea as well as a few other items in a locker that could save one's life (a flare gun comes to mind).

    Of course, I made the life boat tender concept even more difficult. I want it to be towable to 25 kts, unsinkable, and ultralight so I can lift it up on deck, and as long as I need to lift it on deck, it should be designed with fluffy pillows all around it so I cannot scratch the boat. Those fluffy pillows would also not take on water, so they would be fluffly closed cell pillows. More seriously, though, I think a nice ultralight dinghy might not be a horrible idea. It would need to be strong enough for at least some harsh conditions, towable, ultralight and unsinkable. The fluffy pillows I guess I can live without, sort of. (please don't blame me for what happens when you google fluffy pillows).

    The dinghy that I am currently considering is called the TD3 and the design will be out soon. I'll post a link when it becomes available.
     
    Angélique likes this.
  14. Angélique
    Joined: Feb 2009
    Posts: 3,005
    Likes: 317, Points: 83, Legacy Rep: 1632
    Location: Belgium ⇄ The Netherlands

    Angélique aka Angel (only by name)

    Just an idea, but guess the dinghy aft below the cat becomes a bit wide this way, and don't want to miss the bridge deck clearance . . .

    cat and dinghy.png
     

  15. Dejay
    Joined: Mar 2018
    Posts: 350
    Likes: 48, Points: 28
    Location: Europe

    Dejay Senior Newbie

    So what do people think of the tender solution of the harry proa cruiser? It docks and perfectly integrates into the bridge deck (big tender also used as sail drive). I really like the concept but I have no experience to compare it to.

    I'd be curious if this concept makes sense to integrate into a power trimaran design. I like the idea of it being lifted out of the way and being able to load / unload easily.

    I guess as a life raft in case of fire you have the same problem, but fire can be a problem for any choice.
     

    Attached Files:

    Last edited: May 19, 2019
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.