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Thread: tunnel hull prop VS outboard jet... how shallow ?

  1. #1
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    Default tunnel hull prop VS outboard jet... how shallow ?

    Im thinking of buying a little river skiff to keep out all year. I have seen some tunnel hull props but do not know how shallow these really can run versus an outboard jet. Does anyone run both and can share with me some real world data? If the outboard jet would run in 4 to 6 inches of water would the outboard tunnel prop be about the same or not even close?

    The only reason Im thinking of the outboard prop on the tunnel hull would be to save some money and give me a few more options for power. Im looking at a small aluminum boat here like a 1448 or 1648.

    Im thinking fixing the outboard prop and replacing a broken prop would be easier than repairing the jet foot..or is this not true?

    Thanks,

    Mike

  2. #2
    Member Sobie2's Avatar
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    I run with a prop and a jet, using a jet tunnel. The reality is that when I need to run a river with a jet, most of the time my boat is skipping over rocks and pebbles frequently, and you could not run a jet without a tunnel in those conditions. But if you never have to skip over anything, then a prop tunnel with a rockhopper lower unit protector would be the way to go. My 1652 MVJT with a 50/35 was ok as a jet, but crazy fast when I put the prop on it.

    It really depends on the rivers you are running. In Pennsylvania I think everywhere is rocky and bedrocky too so I'd recommend only a jet and a jet tunnel. On the Yukon it is all sand and you can run a prop just fine.

    Sobie2

  3. #3
    Member boondockinak's Avatar
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    X2 on the tunnel for rocky stuff. If it's not in rocks, it's debatable on "my boat is better than you're boat" when talking about a tunnel vs. no tunnel. If you get a boat with a tunnel, built by someone who doesn't know how to build a tunnel, the tunnel can hurt you vs help. Companies, go through great pains to design and test their tunnels to provide maximum efficiency in sending clean (un-aerated) water to feed the jet intake. It's really easy to screw up a tunnel and then just send a bunch of turbulent aerated water to the jet, thus causing cavitation and lack of power.

    If I set up another jon/sled type jet boat (anything from 14'-24'), I would most certainly choose a tunnel. Not necessarily for the "shallower running" characteristics, but simply to keep from ripping off the lower unit or damaging the jet foot from a phantom rock. My little 1448 high side Lowe (non-tunnel) with a 4-stroke 40/30 Merc will run all day long in 6" of water, and I have run it in as little as 1-2 inches for a few seconds. Obviously I avoid any rivers or lines where I know there are potential rocks.

    -Rob
    ~Alaska born and raised~ •'04 Duckworth, 5.7 w/ 3-stg. •High side Lowe, '13 Yami 25 prop+Merc 40/30 jet
    •Ranger 6x •CAT atv w/ 27" rubber •A very large moose buggy •M7 153" "Earned, NOT given"

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    Does anyone (boat mfg.) make a 1448 jet tunnel? I have talked to a few people and it seems the minimum length for an outboard jet with tunnel is 16 feet...

  5. #5
    Member boondockinak's Avatar
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    Not 100% sure about that. Check out some of the major brands like lowe, sea ark etc. Depending on your budget, you can always get something custom from Wooldridge etc.
    ~Alaska born and raised~ •'04 Duckworth, 5.7 w/ 3-stg. •High side Lowe, '13 Yami 25 prop+Merc 40/30 jet
    •Ranger 6x •CAT atv w/ 27" rubber •A very large moose buggy •M7 153" "Earned, NOT given"

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