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Thread: Raft PSI

  1. #1
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    Default Raft PSI

    Ok so I finaly got my raft in September, didnt have a chance to take it out though. Is there a certain PSI ratnig that I should follow? Its a 13ft Alaska Series TDS.
    Don

  2. #2

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    It's awful hard to get a PSI reading from the valves. I go for a decent thump sound on the sides. It will gain a bit of pressure during the day as it heats and less as it cools at night. It is possible to over pressurize the rafts and possible to blow an internal baffle. I think you will know when you blow it up the first time where to stop by feel.

  3. #3
    Member alaskachuck's Avatar
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    Default

    I use the old thump thump with my fist on the tubes. I have a 16 foot cat. Never have seen a setup for them to read PSI. I use a hand pump and pump it up untill there a a good resistance to the pump. I almost never have to add air after that even after putting it in the cold water. On occsasion (this summer was not one of them) I have let air out on sunny warm days as the air will heat and expand. You can also watch your tubes as see how they are around your frame. They should not bow up at all. Just rigid and staight. I have never blown out a bladder in my 5 years of owning this my raft. With the bladder zipped inside the tube I have to think it would pretty hard to blow one out but i can see it happening. Jim King and the boys at alaska raft should be able to shed more light on this subject as well at the other members
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    Default

    2 to 2.5 lbs per square inch is a fairly commonly recommended pressure. They do sell pressure gauges for rafts, but I've never used one. It doesn't seem to be a very delicate issue. You want enough pressure to keep the boat from tacoing in large waves, and to keep the frame from bending the boat, but rubber (Hypalon & neoprene) are a lot more flexible, and feel softer that plastic (PVC & urethane), so the pressure can vary quite a bit and still be fine.

  5. #5
    webmaster Michael Strahan's Avatar
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    Default PSI Ratings on Rafts

    Jim is correct. Rubber boats should take 2.0-2.5 psi and plastic boats take 3-4 psi. You can purchase a pressure gauge that will tell you where you are, which some folks find necessary until they develop a feel for it.

    Remember that the pressure will go up or down with rises or falls in the temperature of the water or air. In some situations it is necessary to add or bleed air as temperatures change, sometimes multiple times during the day.

    -Mike
    LOST CREEK COMPANY: Specializing in Alaska hunt consultation and planning for do-it-yourself hunts, fully outfitted hunts, and guided hunts.
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  6. #6

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    Get one of these pressure gauges. Its a must to get a really good idea of your pressure.



    http://www.nrsweb.com/shop/product.a...19&deptid=1090

  7. #7
    Member BlueMoose's Avatar
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    Default If In Anch

    Alaska Raft and Kayak has them on the shelf as well. BMR will have them this Spring if your in Fairbanks.

    Best Wishes

    Blue Moose

  8. #8
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    Lightbulb Rule of Thumb & PSI

    Many high-end, mainstream boats manufactured w/ decent fabrics & construction are 1/2" deflection upon full inflation.... a good rule of thumb, practical for field conditions. Do this by pushing down mid tube w/ ample thumb pressure once the whole boat is inflated - checking chamber by chamber.

    PSI gauges made specifically for raft valving are available, work excellent, and are easy to read (in the right hands)... 2.5PSI cold is about right for boats like AIRE. True - boats (like AIRE) can take (read as --> can handle) more like 3.2PSI or so... but this is definitely not recommended by the manufacturer.

    4PSI is excessive!!!! and likely (maybe not right away) will cause some failure!!!!

    Nevertheless... Fudge-factoring somewhat on pressure is "built in" on many boats to account for outdoor factors.

    PSI gauges are most useful in conditions that will involve differences in air or water temps and altitude changes. They are a must have for thorough shop diagnostics.

  9. #9
    webmaster Michael Strahan's Avatar
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    Default Thanks, Brian!

    Well, haven't heard from you in a while; what's up?

    Yeah, I must have been sleep-deprived when I wrote that- my point was that plastic boats can handle more pressure than rubber, but not THAT much!

    One more consideration when it comes to inflation (some folks don't know this one). Most boats use internal baffles (bulkheads) to keep the chambers separated from each other. Be sure to pressure everything to shape by working your way around the boat from valve to valve, THEN top the tubes off! If you fully inflate one chamber before moving to the next, you could blow a baffle and then you have one less chamber. Blown baffles can be fixed, but it will cost you, so be careful!

    Regards,

    -Mike
    LOST CREEK COMPANY: Specializing in Alaska hunt consultation and planning for do-it-yourself hunts, fully outfitted hunts, and guided hunts.
    CLICK HERE to send me a private message.
    Web Address: http://alaskaoutdoorssupersite.com/hunt-planner/
    Mob: 1 (907) 229-4501
    "Dream big, and dare to fail." -Norman Vaughan
    "I have climbed my mountain, but I must still live my life." - Tenzig Norgay

  10. #10
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    Default Thanks everyone

    You guys are a treasure trove of information.

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