Adding additional stringers

Discussion in 'Stability' started by dada73, Nov 4, 2023.

  1. dada73
    Joined: Sep 2023
    Posts: 4
    Likes: 0, Points: 1
    Location: Vienna, Austria

    dada73 New Member

    Hi I'm Chris and this is my first post here. Been reading a lot of threads on this topic though.

    So as it happens to others as well I'm about to replace all stringers and bulkheads.

    And as I'm doing this I'm asking myself if it wouldn't make sense to add stringers to further strengthen the boat.

    Options are a center stringers or one or more offset stringers.

    What do you guys think?

    Sidenote: What I definitely want to add is some transom knees to support the engine.

    Ah and we are talking about an 18ft Ski raceboat with a Yamaha 225 6cyl in the back.
     

    Attached Files:

    Last edited: Nov 5, 2023
  2. ondarvr
    Joined: Dec 2005
    Posts: 2,932
    Likes: 579, Points: 113, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    What makes you feel the original build wasn't up to the task, did it fail in its prior life?
     
  3. kapnD
    Joined: Jan 2003
    Posts: 1,301
    Likes: 414, Points: 83, Legacy Rep: 40
    Location: hawaii, usa

    kapnD Senior Member

    If you’re not removing the existing stringers, you could add layers of FRP over them for added strength.
    Adding 2 full stringers will definitely stiffen the boat up, if that’s what it needs, but at a weight penalty.
     
  4. dada73
    Joined: Sep 2023
    Posts: 4
    Likes: 0, Points: 1
    Location: Vienna, Austria

    dada73 New Member

    existing stringers are rotten and need to come out.
    Boat didn’t fail but "factory production" is always a compromise btw. good enough and still being cost effective.
    So thought about an "as good as it gets" construction.
    Here's a picture of the bow section.
    The serail shot shows one stringer knee intersecting with the first bulkhead. The stringer is not continuous but rather interrupted but the bulkhead. Most constructions are vice versa meaning the bulkhead is in between the continuous stringers, right?
     

    Attached Files:

    Last edited: Nov 5, 2023
  5. ondarvr
    Joined: Dec 2005
    Posts: 2,932
    Likes: 579, Points: 113, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    What you see is typical construction for the that time, it's piss poor, yet didn't fail, and other than rotting, most didn't.

    What it means is that it was adequate construction for the decades of use it experienced, even with rotten wood. How do you expect to improve on that by adding more structure, weight and $$$.

    If you rebuild it close to original, but use much more attention to detail, it will be a huge improvement over the original build without additional cost or complexity.
     
    Last edited: Nov 5, 2023
    kapnD likes this.
  6. dada73
    Joined: Sep 2023
    Posts: 4
    Likes: 0, Points: 1
    Location: Vienna, Austria

    dada73 New Member

    Gotcha. I'll add some knees but other than that will stick to the current layout.
    Thanks
     
  7. dada73
    Joined: Sep 2023
    Posts: 4
    Likes: 0, Points: 1
    Location: Vienna, Austria

    dada73 New Member

    @ondarvr reg the bow reinforcements you can see in this pic: do them again like they are with some small wood slats or replace them with something else like a vertical more stringer type of structure?
     

    Attached Files:


  8. ondarvr
    Joined: Dec 2005
    Posts: 2,932
    Likes: 579, Points: 113, Legacy Rep: 506
    Location: Monroe WA

    ondarvr Senior Member

    They didn't fail as is, but you can do whatever let's you sleep better at night.
     
Loading...
Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.