90 Ozark Deck Boat rebuild

Discussion in 'Boatbuilding' started by phil32, Jul 23, 2012.

  1. phil32
    Joined: Jun 2011
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    Location: Indiana

    phil32 Junior Member

    Gentlemen I just purchased a 1990 Ozark 20' Deck Boat hull that has a solid transom and stringers however the previous owner got in over his head and the project stalled. The deck and supports were bad so he tore it out he started replacing it with 2x4s a (real mess).
    As far as I can tell the deck was original supported with 2x2 cross members and 1/4 plywood gusset running from the top of the 2x2 to the hull 24" OC and 1/2 plywood deck.

    There is a crack in the hull at the front starboard side that I need help in repairing and a previous repair in the stern that looks like they slapped some roving woven on it and painted it.

    My plan:
    1. repair the crack in the hull at the bow.
    2. grind out the repair in the stern and see what we have and repair it.
    3. replace the cross member supports with 2x2s 1/4 plywood gussets and tab and glass them in. I am thinking about doing it 16" OC that may be an over kill. Im not sure if it is a sound thing to do to add more weight for the strength.
    4.Flip the hull and make any cosmetic repairs and do some sanding and find someone to spray new gelcoat. I have no experience in gelcoat.
    Flip the hull and deck it with 1/2 plywood and glass it in.

    I would respectful ask for any help you could share with me. I have a little fiberglass experience and good woodworking skills but am short when it comes to the tech details as to best fabric to use for repairs, deck etc and the best wood materials for the reconstruction.
    Thank you
     

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  2. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Yea, you've got some work there all right. The wise course is to rip out all those 2x4's and start fresh. That's a patio deck structure there, not anything remotely close to boat framing. No crown, fasteners into end grain, bad workmanship, even for a patio deck, let alone a boat.

    You should also just grind out the bad 'glass repairs, so you know what you have is good.

    [​IMG]

    Do you have the deck cap?

    Your plan of 2x2's on 16" centers is okay, with the gussets. You'll not add much weight and the deck will be slightly stiffer. This boat isn't a speed demon, so not much worries. Put some crown in the deck beams and make them continuous from side to side. I personally wouldn't use 2x2's, but would prefer 1x4's on edge, with the deck crown cut into them. 3" - 4" of crown will do.

    The key to a stiff deck, is the tabbing used to tie the athwart deck beams into the hull shell. You'll want 2 layers of 12 ounce biax, at least 6" onto the hull shell at each beam/gusset assembly. You can use "legs" to support the deck, but bulkheads or ring frames would be easier and quicker. You only need a few of these, say on 48" centers and the fore and aft stringers can be laid on the flat, notched into the beams and bulkhead/ring frames. Of course all the bulkhead/ring frames need to be tabbed well to the hull shell.

    The fore and aft stringers need only be 1x2's with beams on 16" centers and should be full length. If not scarf them to length. You want to be light, but strong, so don't go crazy with stringer spacing, 16" will do. Try to use knot free stock on the stringers and the beams should have small, tight knots if any. Plywood should be marked "APA Exterior" not "APA Exposure 1". 3/8" plywood is fine for the bulkhead/ring frames.

    Once you've pieced everything in dry, including the 3/8" plywood decking, disassemble it and coat every square inch, including screw holes with 3 coats of epoxy. When dry, tab everything in that touches the hull shell. You can't go wrong if you over tab stuff, but you sure can if it's under tabbed. Ditto with the epoxy coating process.

    Log onto westsystem.com and systemthree.com and download their user's guide for tips, tricks, techniques and application notes. These will explain fastener bonding so you don't get rotten fastener holes, bonding to dissimilar materials (wood to 'glass), material choices, etc.

    Lastly, make sure any moisture that might accumulate below the decks, can drain aft and out a hole in the transom. This is why the boat had issues in the first place. This means "weep" holes along the centerline in structural elements and any place that can trap water, such as adjoining pieces. A 3/4" or bigger hole will let the water out when you park the boat bow high on the trailer.
     
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  3. phil32
    Joined: Jun 2011
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    Location: Indiana

    phil32 Junior Member

    PAR, Thank You. No I do not have all the deck cap, I have the helm and the large rear seat.
    I like your suggestion about the 1x4s.
    In my research I found a deck boat restoration project where he used 2x2s please take a look http://forums.iboats.com/showthread.php?t=471173&page=7

    What is the best way to tie the 1x4 beams on (edge) to the starboard and port sides. I may be over thinking this but I had thought of turning 1x4s flat and routing a grove in the middle to except the 3/8 bulkheads ply and then tabbing everything into the deck hull.

    I understand all beams need crown up but i dont understand how to cut in a crown 3" to 4".
    Also are you calling for APA Exterior (1") for the deck?

    I have the West system and systemthree user guides and study them often. I also have a roll of 1708 and a roll of CSM for the tabbing along with Epoxy resin and some cabosil. Would the 1708 be sufficient for the deck?

    Again, Thank you. It would not be possible for us DIYers to even attempt this without gentlemen like you who are willing to share your years of experience and invaluable knowledge with us.
    Best regards,
    Phil
     
  4. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    On a deck boat the crown isn't as critical as other boats, so a 1.75" crown will do, and will left some "meat" left of the 1x4. Assuming an 8' beam on your boat a curve that is 1.75" tall at the centerline, of the 1x4 will serve as the crown.

    Below is an 8' long 1x4, that has had it's top edge cut into a crown (1.75"). This doesn't leave a lot of meat to attach to the hull, so take the cut off portions and edge glue them to the bottom of the now cut 1x4 (lower portion of the image). It's now a curved 1x4, full length. This gets gusseted to the hull shell and tabbed on.

    1x4's on the flat will not offer the support you need. They'll just flex as you walk around, defeating their purpose. A 1x4 and 2x2 has just as much wood in it, except the 1x4 (on edge) has the wood oriented to best advantage, while a 2x2 doesn't. In other words, it's stronger this way, for the same amount of wood and the same weight.Stringers between the beams can be 1x2's on the flat, notched into the beams. Routing groove into the 1x4's on the flat will make them so weak that you'd not have much to work with. Bulkhead should just butt the bottoms or screwed to the face of the beams (easier).

    3/8" APA Exterior is fine for both the decks and the bulkheads and/or ring frames. 1" is way over kill and 3 times as heavy too.

    1708 will work for tabbing, though the mat will waste a lot of epoxy. Straight 17 ounce biax is a better choice. CSM is unnecessary with epoxy. 1708 on the deck isn't necessary, just a regular cloth. 6 to 10 ounce or multiple layers of light cloth (4 - 6 ounce) will do. The cloth on the deck is for abrasion resistance only. No strength is added.

    I looked at some of the photos over at IBoat and he's making one heavy *** boat. A solid bulkhead under each 2x2, wow, it'll weight a lot. The 1x4's on edge, gusseted and tabbed will be just fine and you'll only need a few bulkheads to support the whole deck. The gussets can be more of the 3/8" APA Exterior, glued and screwed to the side of the beams and shaped to the hull shell, where they land. The IBoat guy is also notching stringers, which is a good idea. I see a lot of mat in his layup, which is fine for his polyester laminates, but useless with epoxy. All your tabbing and attachments will be biax, which is lighter and a lot stronger. There's no place where you'll need or want mat.

    Adding a lot of weight is a common back yard builder's problem. Don't be tempted to make things stronger, with a little of this and that. Most times you actually make things weaker, because of increased point loading and the beefed up stuff is still attached to relatively light weight stuff.
     

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  5. phil32
    Joined: Jun 2011
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    Location: Indiana

    phil32 Junior Member

    PAR, Thank you
    I totally understand the crown and I can jig that up.

    I will keep the beams 16"OC and the bulkheads 48" OC
    Ill asume I keep the Bulkhead off the hull 1/4" and add a peanut butter fillet so as not to create a hard spot?

    3/8 APA Exterior ply for gussets and deck. 3 coats of epoxy on everything.

    Order some 17 ounce straight biax for tabbing
    (6" each side Bulkhead to Hull) and regular 10 ounce cloth for the deck.

    One thing I am not clear on is tying the beams into the starboard and port sides could you explain.

    Being an old Homebuilder, I have the mind set of beefing it up to make it stronger. Your method coupled with epoxy and cloth takes me some time to adjust to.

    Again thank you.
    Best regards
    Phil
     
  6. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    The gusset permits a large perpendicular surface area next the to hull shell. It's the gusset that is physically tabbed to the hull shell.

    6" tabbing is a minimum. You can't go wrong with bigger/wider, but you sure can if too light or small.

    Make sure not to make the bulkheads like the guy over at IBoat. Cut holes in the middle of them, unless they are storage compartments. Leave a 4" (minimum) flange around the perimeter of the bulkhead unmolested. A plywood bulkhead (ring frame) like this is the same strength, but a fair bit lighter than a solid hunk of plywood.
     
  7. phil32
    Joined: Jun 2011
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    Location: Indiana

    phil32 Junior Member

    PAR,
    I have been studying (Ring Frames) and with your explanation I understand why and how to build them.

    I am not clear on connecting the deck beams to the hull sides port and starboard.

    In the iBoat project he created a slot for the deck beams to set in. Should I do this or do you have a better suggestion.

    We have had 100+ weather here everyday. I'm hoping for some relief to get started on the demo.
    Again thank you,
    Best regards
    Phil
     
  8. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    A slot shows how Mickey Mouse the IBoat guy is. It's not an erector set.

    Picture a triangular piece glued and screwed to the ends of each beam. The outboard end is shaped to the hull shell, where they will live. These get filleted and taped to the hull shell, holding the beam up in the process.

    Notice the gussets don't go all the way up to the top of the beam. Leave them short about a 1/2". Tab the gussets just like bulkheads, to the hull shell with lots of tape. They're a little out of scale here, being on the too big side, but you get the idea. If they're visible or you want to save more weight, they can have holes cut it them (just like a bulkhead). Great for rod storage if they are used in cabin roof beams.
     

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  9. phil32
    Joined: Jun 2011
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    Location: Indiana

    phil32 Junior Member

    PAR Thank you
    Have had a few days of under 100 degree weather and was able to strip all the framing and foam out. I discovered the only place no drain holes were provided was in the knees and they were rotted out. I have core drilled the transom and the stringers and they are solid. It looks to me there were 4 2' OC Beams across and supported from atop the stringers with braces. Enclosed some pictures of the tabbing. Hard to believe this is all that was holding the Deck. I see how much easier it is to just brace the Beams off the stringers.
    Is it ok to set the ring frames on top of the stringers or should I bypass and tab them to the hull.
    In addition while I have the opportunity to replace the knees should I use anything else besides the 1/2 Ply that was used.
    Again thank you for all your time and advice
    Best regards
    Phil
     

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  10. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    If you set the ring frames on top of the stringers, they still need to be "tied" in with tabbing. The idea is a continuous bond to the hull shell, regardless of how many pieces might be involved.

    Weep holes (drain holes) or the lack of the, are notorious for killing boat parts. Don't make this mistake.

    When you drill transom core samples, take them from just below bolt holes and the very bottom of the transom on the centerline of the boat. These are the usual locations for rot (it's a gravity thing).
     
  11. LP
    Joined: Jul 2005
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    LP Flying Boatman

    Phil,

    You are getting some of the best advice on the forum. Paul knows his stuff. I try to soak up everything I can that Paul posts. :cool:

    I think that this thread is particularly useful as I can see this as a fairly common type of repair.

    Points to both of you, but Paul already has too many.:p
     
  12. phil32
    Joined: Jun 2011
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    Location: Indiana

    phil32 Junior Member

    LP,
    Thank you for the reply. As a backyard DIYer PARs knowledge and dedication to his craft has been invaluable. I have found he not only tells you how to fix the problem, but he teaches you along the way. He teaches you the HOW and the WHY. Some of the terms and words he uses to describe the problem and the solution, standard in the industry but foreign to the DIY causes you to study and search for the meaning and understanding. I have always been interested in boats, at age 14 had my first little wooden fishing boat. Its always been a passion for me, now retired my daughter also a boating nut have enjoyed many hours of learning and working together on these boats. None of this would be possible if it were not for this Forum and people like PAR willing to share their years of expertise with us. I have read 100s of his posts, HE IS ONE SMART PUPPY and defines what a TRUE PROFESSIONAL IS.
    Best regards,
    Phil
     
  13. LP
    Joined: Jul 2005
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    Location: WNY

    LP Flying Boatman

    ....and to post what I originally set out to say. Your 1x2's can mostly be gotten out of larger 2x material. The longer (and wider) dimension stuff will more often have those long, knot free spans that we need for boat lumber. When I was in Kansas, Lowes there would carry 12', 14' and 16' Southern Yellow Pine that could be had with tight grain and few knots. Now I'm in New York and I am finding the same only out of Doug Fir. Both are good woods though SWP will be a bit heavier and some have concerns about SYP and epoxy use. I've not had a problem with it. I don't know what you will find in Indiana. You may already be aware of all of this.

    Good luck on your project. Feel free to post progress photos. There are many here that will be interested to see your progress. Sometimes we live vicariouosly through other's projects. My table is full though my progress is slow at times. So much to do and so little time.
     
  14. phil32
    Joined: Jun 2011
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    Location: Indiana

    phil32 Junior Member

    Repairing Crack in Hull

    PAR, I have ordered the cloth, resin, cabosil and wood and I would like to repair the crack and flip this boat and finish the hull and be done with it.
    I have decided to take your advise in former posts and paint the hull instead of gelcoat.
    I am asuming I need to repair the crack from the inside first. Would you kindly tell me the best way to repair this crack before I flip it.

    Thank you,
    Best regards
    Phil
     

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  15. phil32
    Joined: Jun 2011
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    Location: Indiana

    phil32 Junior Member

    I have now ground down the crack and can see the extent of the repair. I have some Roving Woven cloth that was used to build the boat but am wondering if I should use light weight biax cloth and some CSM and build up layers for the repair from the inside. The West system says to use the same cloth the boat was built with but I understand lighter cloth and layers, but giving the location of the crack I need strength. Any advise.

    In addition how far should I go around the crack with cloth to get good coverage and a strong repair.
    I then want to flip the hull and finish the repair and paint the hull.
    Thank you,
    Best regards
    Phil
     

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