Tenders stored on foredeck

Discussion in 'Boat Design' started by sabahcat, Nov 23, 2010.

  1. michael pierzga
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    michael pierzga Senior Member

    The" under over " solution that you picture is one of the most attractive ,functional storage solutions that I know of. under for harbour work....nightime haulout and day sailing, over and on deck for at sea work. Many of the very finest yacht use this line of thought.
     
  2. sabahcat
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    sabahcat Senior Member

    Pretty sure it is Brian
    There are a few versions of it getting around in australia
    Have seen sizable boats built from it so I imagine for my 3.8 m tender it'll be fine
     
  3. brian eiland
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    brian eiland Senior Member

    Some Rough Sketches

    I appreciate what you are getting at here, but in a mid size tender a center console and and some seating are features most of the boat owners are seeking. Leave them off...lose customers.

    These are a few sketches of that RIB I proposed in #138 above
     

    Attached Files:

  4. Alik
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    Alik Senior Member

    I tested small boat with such tri-hull recently; initial stability is very low that is a problem in case of tender. Underway on oblique waves, the boat was directionally unstable.
     
  5. brian eiland
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    brian eiland Senior Member

    http://www.novurania.com/

    On this vessel I see that the bow rails eliminate a lot of potential seating area, and that stern seat eliminates a lot also. The center console is too big The stern area is wasited. With D-type tube concept this vessel would offer a lot more usable space.

    If storage on the bow is comtemplated then you want a tender that will IMMMEADIATELY empty itself of all water that it might collect from a big wave, a bow burying event, etc. This vessel would act like a big tub with a slow drain. It needs an open transom of some sort.
     
  6. Alik
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    Alik Senior Member

    Yes, D-tube is good idea for cockpit space and we have 3 designs launched with this concept, BUT the boat is heavier.
     
  7. brian eiland
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    brian eiland Senior Member

  8. Alik
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    Alik Senior Member

  9. CatBuilder

    CatBuilder Previous Member

    A couple comments:

    First, you couldn't sit on the tubes where the bow rails are. Your feet wouldn't touch the sole and you'd flip out too easily. I agree the stern area is wasted and could have been used more. However, it houses fuel and batteries, IIRC. Bilge pump, too, I think. It was a few years back, so I'm not recalling.

    This boat didn't go to sea. It was a *tender*. We used it in protected water to go diving and to go ashore when at anchor. None of the safety issues you are bringing up were relevant to the use of this boat as a tender to a megayacht.

    This gets back to my initial post. We all have different uses for tenders. You are assuming there could be a "bow burying event", but in reality, I could plane all the time because it was so calm, or was idling through no wake areas in harbors with it.

    If I had to go to sea, I sometimes used the other tender, although the RIB gave a much better ride in rough conditions:

    [​IMG]

    Either way, these were *tenders* (to a large boat) and were not used to battle poor conditions. I had a 33M (110ft) vessel with active stabilizers to take care of rough conditions at sea. In the case of going to sea in the large vessel, both of these boats were up on our aft deck (top level). These were used for fun, for leisure and for transportation in harbors... the same way 99% of all tenders are used.

    BTW: I like your tri-hull tender! :) Very nice.
     
  10. michael pierzga
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    michael pierzga Senior Member

    Gee Brian as I said...many different solutions to a tender. Some people need toys so obviously a high speed, wind in your face, lets do a tour, tender is the way to go. For everyday, primary tender, toys wont work .

    Your multi hull tender has merit... many people love the load carrying ability and space. Wide tenders are much easier for Old folks to board and find a seat in. I actually have a boarding ladder built into my tender for old folks access. By all means explore the design possibility. Make it 3.5 meters and I might buy one tomorrow. The Nautica Cat is very popular on the superyachts. http://www.nauticaintl.com/Boats/Catamaran/catamaran17.htm

    Get rid of the sharp egdes on your design .. this weekend Im repairing the sharp underwater edges of my tender , with epoxy and Biax tape. Make them soft and able to absorb bumps. I " bump" the tender every time I store it. I also "beach" a tender, because the guests , want to go to THAT restaurant on the beach, the small port has no available tender loading , unloading space, 50 times a season.
    And jet...forget it. I have zero experience with jets ski. The yachts around me use castoldi diesel jet tenders. Expensive first class gear, And they curse them because of flooding damage and lack of spare parts, particularly jet bucket pieces, on the road. Realize that many times I am operating my tender in extreme shallow water...outboard tilted up, prop nearly spinning in the air, in order to access places of intrest on the inside of an esturary. A jet would die..clogged with weed and junk.

    http://www.castoldijet.it/jettenders/model14.php
     
  11. brian eiland
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    brian eiland Senior Member

    Maybe a slight misunderstanding here. I wasn't talking about the tender going to sea on its own...rather I was talking about putting a tender on the front tramp area of my gamefishing cat (keep it out of fishing area), and my concerns that it could fill with water and become a problem in storm conditions. I wanted that tender to be fully drainable in seconds.
     
  12. brian eiland
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    brian eiland Senior Member

    That is a very nice tender, but it could have much more 'usable space' with D-tubes, and better treatment of that aft area that is essentially corrided off. Either make an aft seating area covering that stuff in the stern, and/or push some of it up under the console.

    I totally agree, too sharp an edge on the underwater sponsons. But I had though they might be fashioned of tough rubber bumper material such as THIS, or THIS
     
  13. michael pierzga
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    michael pierzga Senior Member

    And Brian..your " D" section is very worthwhile. The major cause of tube failure on every Rib Ive ever owned is the interface between tube and the rigid bottom..On the inside of the rib. This deck to tube joint become full of sand and stones and chafes thru the tubing, destroying the tube. Very complex to patch this area. For the past few years I have, to prolong the life of the tube by preventing debris from accumulating, caulked the deck to tube interface, skin to hull , with cheap silicon seal...seems to work. Better to eliminate this joint.
     
  14. sabahcat
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    sabahcat Senior Member

    On a small scale, but built using Polycore/nidacore/naidaplast/hexacore (whatever they want to call it this week)

    http://www.multihullhaven.com.au/Mk_2_elevator_Miss_B_Haven.jpg

    Interesting wheel design
    Free replacements found on almost any beach in these parts
     

  15. brian eiland
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    brian eiland Senior Member

    Nice and clean and simple
    ....but it needs some really big drains for my liking :D

    ...and its got those ramp/beach rollers Michael was requesting

    I had thought something like this could be rotomolded from polyethylene or similar
     
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