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Thread: Reverse Chine / Plaining strakes

  1. #1
    Member willster33's Avatar
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    Default Reverse Chine / Plaining strakes

    I am having a bit of hull work done, the result of a rough Yukon trip last fall and the shop I have selected has told me that I can get better load carrying if I add some reverse chine. I have struggled with weight management on this boat since I got it. It just will not hall the weight my friends smaller jet boat will. There are major differences with our two boats. His is a North River 21' with the Hamilton 213 pump and Kodiak 6.0 and a soft top, It was amazing the kind of weight he could hall. I have an older 24' USCOLA with a hard top and a Kodiak 8.1 HO and the Hamilton 211 jet pump. Now we are talking about carrying 120 gallons of fuel in on board tanks with an additional 350 gallons in thirty gallon drums on deck. My friend was a bit smarter in that he went light on all the gear he took but we were comfortable and he was not. Another note we had to set 4 drums off my boat and he did not and it would take me literally miles to get on step. Once on step I could run 32 miles an hour a 3k 3.2k rpm and he was flirting with 4k rpm and falling behind. Any one with experience with the addition of Reverse Chine or Plaining strakes out there? Any thoughts on how these will work out for me? I sure hope they work as I am heading back to the dulbi this fall and would like to be confortable again
    Will

  2. #2
    Moderator bkmail's Avatar
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    Default

    Sounds like they should work. I have them on my Alumaweld and it handles well, hauls a load, and jumps on plane quickly.
    Wooldridge uses them on thier boats and they flat out perform.
    If Gary at Greatland welding is doing the work I doubt you'll be disappointed.
    If you have any doubt, contact Glenn Wooldridge...
    BK

  3. #3

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    You may not have a turbo impeller in your 211,huge difference, I don't think they were available in them. What impeller do you have, how tight? You can add a cavitation plate to help get on step, you can run longer at WOT with out the jet slipping as you are trying to get on step.
    The North river may be as much as 1000 lbs lighter than your boat. When you leave Galena hug the right shore in that first right hand corner before you cross over to the slough if you don't get on step here it is a long ways to find some shallow water to help you out. We would get in 2-3 ft to take off with our boat loaded heavy,495 gal of fuel 2 guys, one black dog, wall tents, steaks no freeze dried food for 14 days. That was the good ol days when gas was 1.55 a gal.
    If you put strakes on just have them tacked on and try the boat if it is too much they are much easier to cut some off.

  4. #4
    Member anonymous1's Avatar
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    Default Reverse Chine

    I have built a couple of reverse chine set net skiffs. 1st picture is 24' x 8.5' about 8 degree of deadrise and a 12"x 4" reverse chine that follows the hull lines forward and begins to taper as the hull narrows. Powered with a 150hp Cummins 4bt coupled to a Hamiton 211.

    Its a heavy boat. 4800# with 50 gals of fuel. when new it would jump on step pretty good with an additional 1500# pay load after that forget it.
    We put all the hull framing on the inside to prevent air trapped between strakes or stiffners from getting sucked into the intake.

    Its very very stable because of the added bouyancy and surface area of the reverse. Also very dry. The off side is it pounds pretty hard because of carrying the width of the chine so far forward.

    Next picture is of a bottom replacement we did on a similar sized skiff. On this one we have about 12 degrees of deadrise with the same amount of reverse chine width and depth at the stern.
    This time we did not follow the hull line all the way forward. We laid it out parallel to the center line and let it taper out to the side as the hull narrowed. This boat pounds way way less and seems to move a little easier. With twin F50 Yamahas it will will pack a lot more and out preform the other.Maybe a little wetter though.
    I have owned a lot of small boats and I`m sold on reverse chines for stability, carrying capacity and dryness as the best way to get more out of a small hulled craft. IMHO
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    Member willster33's Avatar
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    Default looking forward

    Looking forward to getting my boat back and seeing what it will do. I should be able to put her in the water when I get back in May. I have the 4.0 impeller in the 211 jet, and I did take it in to A1prop in Anchorage and had the jet gone through before the described hunt and it was machined and tight. I also called Schlagel Marine because they do lots of jet and impeller work and they don't have any upgrades for the 211, someday I will upgrade to the 213 or 241 but not yet, the upgrade is very expensive and will have to wait. If any one knows of anything that can be done to the 211 pump short of changing it out it sure would be appreciated. And what is a cavitation plate?

    Thanks Will

  6. #6
    Member Gerberman's Avatar
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    Default lifting strikes and reverse chines

    I put 3 lifting strikes on each side and reverse chines one my 34 foot boat, and it jumps up on step and rides a lot dryer. The down side is top speed is about 4 mph slower, more drag in the water. I only carry 386 gallons of fuel. Have fun.

  7. #7
    Member alaskabliss's Avatar
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    My 21' Thunderjet has the reverse chine hull and strakes and it performes awsome. I have hauled some impressive loads and never been dissapointed. I am running this with a 350 small block and 212. It will get on plane very quickly and run very shallow. It will beat you in choppy water though. Think of your hand cupped and slapping water.... Thats what it feels like. Good luck with the project and be sure to let us know how it performes

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    Quote Originally Posted by alaskabliss View Post
    My 21' Thunderjet has the reverse chine hull and strakes and it performes awsome. I have hauled some impressive loads and never been dissapointed. I am running this with a 350 small block and 212. It will get on plane very quickly and run very shallow. It will beat you in choppy water though. Think of your hand cupped and slapping water.... Thats what it feels like. Good luck with the project and be sure to let us know how it performes
    Do you have any pictures of what they look like on yours? Really curious about this project.

  9. #9
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    My boat has the reverse chines and lifting strakes and it will haul all you can put in it and get on step in two boat lenghts. It has a 8.1 HO and 212 jet with the Turbo impellor.As far as adding some lifting strakes or chines? I think tacking them on and trying them is a good idea when modifying an existing hull design.

  10. #10
    Member willster33's Avatar
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    Default Excelent

    I have been working with Vanweld North and Nick wanted to tack them on and run her around the lake a bit to see if they worked fine. I think it will never perform like the 212 but it should be better then before. Trying to post a picture of the old tub
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    Hey Will,

    Thats a good looking boat. I think your doing the right thing by trying the strakes and then welding them if they work like you want.

  12. #12
    Member alaskabliss's Avatar
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    Quote Originally Posted by rambling raven View Post
    Do you have any pictures of what they look like on yours? Really curious about this project.
    Im at work for another week but you may be able to go the the thunderjet website and get some pictures. I will try and take some when I get home... Unless the honey do list is to long!

  13. #13
    Member willster33's Avatar
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    Default Finished

    I finally got to put the boat in the water last time home and what a difference the new chine has made. It get's on step a lot faster and feels like it is force feeding my jet; before I had to be very careful when trying to take off or else the jet would cavitate sp? and I would have to back off a bit until I was moving good then I could pretty much do as I wanted because the boat is so heavy. Now I can just throttle up and take off. Another benefit I noticed was when in the salt water I would get a lot of wave steer before and it could be quite a work out; but now it holds my line very nicely. I did take some pictures but failed to bring them to work with me but I will post some when I can. Nick at Vanweld North added two twelve foot chine's to each side adding quite a bit of lift. Also the boat rides more level now without using the trim tabs. I did loose around eight miles an hour with this mod, but I was very rarely able to go 51mph before any way. I can still hit 43 and that will have to do I guess.
    Cheers
    Will

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