Results 1 to 9 of 9

Thread: Inboard jets on lakes/oceans

  1. #1
    Member Yukoner's Avatar
    Join Date
    Aug 2007
    Location
    Whitehorse Yukon
    Posts
    1,343

    Default Inboard jets on lakes/oceans

    How do IB jets perform on flat water? Do they cavitate much in chop and when you are going slow off step in larger waves?
    Any better performance than jet pumps on outboards?
    Never wrestle with a pig.
    you both get dirty;
    the Pig likes it.

  2. #2
    Member emartens123's Avatar
    Join Date
    Oct 2006
    Location
    Northern BC
    Posts
    36

    Default

    In my limited experience,most jet boats will rattle your teeth out on lakes. Having said that I now own a 17 ft Firefish that has the variable dead rise that goes from 12-8 degrees and what a difference it makes,cuts through the chop almost like a lake boat and next to zero cavitation.It's one of the reasons why i bought this boat.
    Had the boat out this yr on one of the local lakes and had the wind wip up 2-3 ft chop, no problems with the boat.
    I used to own a Valco river boat and that thing would drive you to the shore every time the wind came up and yes it cavitated like crazy.
    The shape or design of the bottom is going to play a big factor in how well the boat will handle chop on lakes
    Up there in the Yukon i can see where it would be nice to have a boat that would handle both lakes and rivers with very little teeth rattle
    How does your Wooldridge handle chop on lakes?
    The Wooldridge was one of the boats that was on my list when I bought my Firefish.

    Later
    Eric

  3. #3
    Member Ronster's Avatar
    Join Date
    Feb 2007
    Location
    Valdez
    Posts
    684

    Default

    My Hewes handles the waves just fine, had it out in PWS this summer in 3+ and just had to slow it down a good bit. It also makes a big difference if your are in a following seas situation which tends to keep your jet out of the water. I would think that it really depends on the boat though as the deadrise is different with each model. I havent had any problems with lakes either with the exception of sucking up lots of lillypads and the occasional seaweed out in the salt.

  4. #4
    Member broncoformudv's Avatar
    Join Date
    Apr 2006
    Location
    Anchorage, Alaska
    Posts
    4,670

    Default

    I agree with what Eric said. My experiences have been the same, some boats do better in the chop than others and I seldom have any cavitation unless I am really beating myself and my passengers up. The outboard jet is nice since you can swap from a jet unit to a prop on it rather quickly and save yourself some serious gas money. When running an outboard with a jet or an inboard with a jet I didn't notice much of a difference with cavitation on boats that has similar deadrise.

  5. #5
    Member
    Join Date
    Jan 2008
    Location
    Anchorage
    Posts
    895

    Default

    My little outboard Wooldridge Alaskan and now my bigger xtra plus inboard both cavitate with big chop. The AK being much worse of course. A steeper bow like on the sport models and more deadrise in the rear would help I bet. The trade off for a shallow running boat is to lose teeth when the wind is blowing up river. I would think that all things being equal, say both boats are a 20ft xtraplus, that the outboard would cavitate more just because it is further in the rear. When the back of the boat lifts up, it will be out of the water first and the longest compared to the inboard's intake grate. I think the IB jet would be better because it has more impeller to bite whatever water is there. The white water guys sing praises for the turbo impellers because they cavitate less. I hear the 3 stages are good for air in the water too.

    So, what is up your sleeve this winter? Thinking of getting that XP with a big fat 350?

  6. #6
    Member
    Join Date
    Apr 2006
    Location
    Tennessee
    Posts
    3,568

    Default

    Our 25 foot Thunderjet Maxim did just fine in the ocean with up to a 2 foot chop. Bigger than 2 1/2 feet, forget about it. I am not a fan of having one boat to do everything but IMO a big inboard jet is about as close as you can come to a good dual purpose boat.

    The heavy weight of the boat helps it run smoother in a chop. Where as a lighter boat bounces around to much.

  7. #7

    Default

    Quote Originally Posted by Yukoner View Post
    How do IB jets perform on flat water? Do they cavitate much in chop and when you are going slow off step in larger waves?
    Any better performance than jet pumps on outboards?
    As many have mentioned, the steeper the deadrise the less likely you'll cavitate in chop but the more water you need to get on step. We sold a North River Seahawk inboard jet with the same 18 degree deadrise as the Seahawk with an outboard and I'm told it handles equally as well in the rough seas. NR claims it will run as shallow as there popular commander models but definitely needs more water underneath to get on step. The steeper deadrise provides cleaner water (less chance of air) to the jet.

  8. #8
    Member jrogers's Avatar
    Join Date
    Apr 2006
    Location
    Anchorage
    Posts
    1,539

    Default

    A big inboard jet will work in the ocean, and trim tabs will make a big difference. Unlike a good ocean boat, you will take a lot of water over the bow and slow down a lot when you get into head seas. You also have to really watch out for kelp with a jet, since it will clog it and a stomp grate won't do much. I started out with a 24ft jet boat and ended up with an ocean boat.
    2009 Seawolf 31'
    www.seawolfmarine.com
    Fully Loaded

  9. #9
    Member Jimw's Avatar
    Join Date
    Jul 2006
    Location
    Alaska
    Posts
    452

    Default

    i have to agree with Halibutgrove....

    I have never had a problem on both lakes or oceans. I have a little different set up than most. I have a 14 degree dead rise where most IB jets are running a much less of dead rise. Alot of people who have IB's and have riden in my boat comment on how smooth the ride is in chop or on the ocean. Of cousre when you are in 2-3 foot chop you are going to have to cut back on the power. But as for the "pounding" and water over the bow, running in Seward and PWS I have not had to many issues. I have ran in 10' swells with 2-3 chop coming across bear glacier in seward with no issues other than common sense of throttling back and using the throttle to go up and over the swells. i had some small issues with kelp and what ever that stuff is that is floating all over PWS. The stomp grate took care of it, and a stainless steel impeller helped out as well.

    THe only real issue I ran into was comming into Seward harbor about 12:00noon with the 3-4 footers stacked up 4' appart. Heck even the 22' sea runner had to chop the throttle as well.

    Cavitation has never been an issue in lake chop or rough water even running at 35mph with the slow rollers in the ocean
    2005 20' Weldcraft Sabre XL 350 MP
    SD309 AT
    2009 Polaris Dragon 800 163
    Custom Mod's

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •