Light weight boat fendering.

Discussion in 'Powerboats' started by PetterM, Feb 15, 2009.

  1. PetterM
    Joined: Sep 2004
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    PetterM Senior Member

    Without using RIB air tubes, what options are there for light weight fendering for high speed boats.
    Anyone know what this fender is made of?
     

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  2. robherc
    Joined: Dec 2008
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    robherc Designer/Hobbyist

    My bet (without any further information or research = small bet) is that it's made of some form of flexible foam, covered with vinyl. (like your butt-cushion to take to the ball game with you).

    ...My biggest question here would be: WHY? That all-around bumper has to have cost 5-10 times what a decent set of RIB air tubes would've cost, and it probably isn't as durable.


    ...Just my $0.02
     
  3. PetterM
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    PetterM Senior Member

    Thanks for your replay. :)
    I have been operating/designing/constructing RIBs now for about 10 years.
    5 – 10 times more expensive? For a 20-25 foot RIB I have had quotes for hypalon tapered tubes at about £1800 plus fitting.

    WHY? The motivation is too reduce maintenance, and with foam we can use a “D” or similar cross section and increase the usable space inside the craft. I have not used foam filled fenders or tubes before and I am keen to learn more.

    Any good manufactures you could recommend?
     
  4. robherc
    Joined: Dec 2008
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    robherc Designer/Hobbyist

    I have no idea on manufacturers...but I'm sure doing a google search for "flexible foam" "impact foam" or "cushion foam" would give you some results.
    As far st the 5-10 times more expensive, I have never worked with RIBs, so I guess I was thinking of a diff. king of fender than you were! I was thinking of the hang-over-the-side inflatable fenders like the ones that can be purchased at even Harbor Freight (here in the US) for about $15-$20 per fender...BIG price difference! (oops)
     
  5. Commuter Boats
    Joined: Oct 2006
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    Commuter Boats Commuter Boats

    The boat building firm" Safe Boat International" http://www.safeboats.com/default/index.php builds aluminum boats with the type of fendering you're referring to. I know that several years ago they were willing to custom manufacture collars for other builders, I think I heard that they're so busy with a government contract ( US Coast Guard) that they are no longer soliciting that work but maybe a helpful contact.
     
  6. snog
    Joined: Jan 2009
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    Location: sweden

    snog New Member

    Petter,

    its hard to see in the picture, but the collar you are looking for might be a PUR-collar, made of coated polyurethane. PUR-teknik in Denmark provides these. I think both the Norwegian and Swedish sjoereddningssellskap use these.
     
  7. PetterM
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    PetterM Senior Member

    Thanks for your help.
    I will contact the Danish to see if they have a viable option.


     
  8. FAST FRED
    Joined: Oct 2002
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    FAST FRED Senior Member

    A simple C shaped base will allow fendering to be strung end to end to create a bump collar.

    Many Euro boats that use canals will have a 3 or 4 inch rope instead string fore & aft in a rail channel.
    Polly pro is light when dry so the weight increase isnt too bad.

    FF
     
  9. PetterM
    Joined: Sep 2004
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    PetterM Senior Member

    Thanks for all your help.
    In order to get a good finish I think Hypalon over foam will be the way to go.
    Still investigating though.
     
  10. Typhoon
    Joined: Mar 2009
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    Typhoon Senior Member

    I've fitted full length fenders like that to workboats up to 20ft. We used sheets of 1" EVA foam cut to width then laminated right to the side of theboat with contact adhesive. We did it this way to get a good fit to the hull, it allows you to cut wedge shaped foam or steps to fit the curve of the hulls and end up with the fender nice and vertical, especially around the bow. Gluing it all up on the hull also make sit much easier to work with and mark the vinyl up.
    They we'd run an aluminium extrusion along the top of the gunwhale with a rope track in it.
    Then the fun part! We'd cut and shape PVC to match the top and bottom curves on the hull, cut side panels and sew it all together, then fit to boat. Sometimes you could slide the covers in the extrusions, sometimes around the bows, you'd unscrew the extrusions, slide the covers on then screw them back down. Right at the bow where the extrusions can't take the hull shape, we'd sew several extra layers and just screw into the gunwhale with large washers.
    At the rear we'd fit several sturdy eyes and lace the covers on, so we could pull the covers back tightly along the hull. Mind you, if they're done correctly they'd be a nice fit anyway.
    Depending on the boat, the bottom fastening to the hull could be many small stainless steel eyes screwed into the hull, or another aluminium extrusion. The extrusion is better on boats that will see a lot of chop, but we never had problems with water pressure getting behind the foam on Sydney harbour on 20ft Yamaha workboats. I personally preferred lacing the bottom of the covers on, it allowed you to get nice tension on the covers. Whatever method you used, punch eyelets along teh bottom of the covers about every 18" to alow any water to drain out.
    The vinyl took plenty of abuse, barnacle encrusted piers as an example, however, there was always one hero who could destroy them.:rolleyes:
    We were only using a middle weight vinyl too (Ferrari precontraint from memory), there are some very heavy duty vinyls out there, the material used in Tautliner trucks is a perfect choice. We could turn around a 20 footer in about 12 hours work.
    I never saw one come back in 5 years.

    Regards, Andrew.
     

  11. apex1

    apex1 Guest

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