Stejcraft rebuild - question re floor

Discussion in 'Powerboats' started by Jkain4343, Dec 5, 2022.

  1. Jkain4343
    Joined: Mar 2022
    Posts: 2
    Likes: 0, Points: 1
    Location: Australia

    Jkain4343 New Member

    Hi all,

    Im rebuilding 4.5 m glass stejcraft
    I’ve just put in a floor which goes from the outside strake (rather that the chine) leaving outside strip of hull which has no “floor” over it.
    I have beefed up these outside sections. Before putting the floor down I put 2 layers of 400gm double bias, then I put 3 layers of 400gm biax ontop of the floor and out across the section between the outer strake and chine. (see diagram)
    I see many boats have a sort of stringer which goes along that strip of floor/hull and attachs to the front bulk head (see pic) I was wondering if these are structural or more for storage purposes?
    If they are structural, I was wondering if I require them as I have reinforced that area and its only 250mm wide. Also I would like the extra deck room.
    Could be a stupid question but still learning
    cheers
     

    Attached Files:

  2. fallguy
    Joined: Dec 2016
    Posts: 6,757
    Likes: 1,381, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    In most rebuilds, you build back what was there.

    The sole or hull should have been tabbed to the hullsides, which you do not show in the drawing.

    There is really no reason to add a longitudinal stringer so near to the hullsides, but tabbing would be wise.

    Your work looks good as well, if I may.

    If there is gelcoat on the hull insides; it must be removed for tabbing, but it looks like your margin there is kinda poor now, so a nice fillet and tabbing would be good.
     
  3. fallguy
    Joined: Dec 2016
    Posts: 6,757
    Likes: 1,381, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Something like 48 ounces staggered at 20mm. I show 2 for simplicity. I also do not show a fillet.
    5AC75237-EE3A-4983-A1D0-F8CD2E6C7825.png
     
  4. Jkain4343
    Joined: Mar 2022
    Posts: 2
    Likes: 0, Points: 1
    Location: Australia

    Jkain4343 New Member

    Thanks fallout guy.
    Yes I was considering tabbing to the hull wall insides but didn’t do as I didn’t think it was necessary… but sounds like it is. I can easily do a bit of sanding of gelcoat and add some tabs as you suggested.

    my only concern is there was originally a hollow fibreglass stringer there as shown in edited diagram. Not sure if this was structural or just for storage tho
     

    Attached Files:

  5. fallguy
    Joined: Dec 2016
    Posts: 6,757
    Likes: 1,381, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    I'm making some assumptions here that the stringer was to minimize the hull flexing at the step, but because you have done all the glasswork, combined with good tabbing 10" away; it can likely be eliminated.

    None of us here have any idea how well the original hull was built. A very thin skin and that step could lead to flex as the vertical portion is stiffer than the areas adjacent to the vertical. Overtime, mechanical fatiigue would occur; leading to gelcoat cracking.

    What I would do, honestly, is get underneath the boat under that location or 10" in at the vertical and push up on it with all your might and see if you can get deflection. If you get some movement; you can add glass, more than you have. 600/225 or 1708. Otherwise, hull tabbing and the xtra glass you already added will be enough.

    But only you can judge whether your work has stiffened things up a bit to elim the old method.
     

  6. fallguy
    Joined: Dec 2016
    Posts: 6,757
    Likes: 1,381, Points: 123, Legacy Rep: 10
    Location: usa

    fallguy Senior Member

    Ths role of the stringer, if you have not lowered the sole, would be to elim flex due to the vertical section.

    All the work you did ought to do the same. 902FF4FB-D778-4332-B4BF-C9BD80E2BAC6.jpeg
     
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.