Restoring an old boat, starting with the floor.

Discussion in 'Boatbuilding' started by jsass, Jun 21, 2004.

  1. jsass
    Joined: Jun 2004
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    Location: Boston, MA

    jsass New Member

    Hi. Let me first get right to the point. If you care to hear my whole situation, please read on. Otherwise skip down a few paragraphs as I am going to rebuild the floor on my boat.

    An opportunity came along and I got an old boat very cheap. Problem is, I know nothing about boats. So first let me tell you about the boat. It's a 1969 14' Columbian Celebrity. When I first saw it, it look a bit dirty. The previous owner said he hasn't used it in two years, which in that time leaves, small branches, and bees nests occupied the inside. But the motor started right up when I asked if it ran. So I decided it was still a good deal for me as I like to fix things and have thought about getting a boat many times in the past.

    So I got the boat to my place last night (Saturday), but it was just after dark so I didn't do anything. So when I woke up this morning, I went right out and got to work on cleaning. After getting all the leaves out and evicting some bees that held on during the ride to my place, I realized that the floor was cracked. Not a surprise though, as I expected flaws, as like I said, I got the boat for a very cheap price.

    So, as I know nothing of what I'm getting into I called a friend who has his own boat. He said that it's not uncommon. And that I could fix it with epoxy and fiberglass.

    I went back to the boat and started poking around the crack, and my screw driver was pushing thru the wood like a wet paper bag. Realizing that the wood was shot I ask my girlfriend to go grab me a pair of pliers. She came back handed me the right tool, but shyly asked, "Is this them?" She's so cute. Anyways, that's off topic. I started ripping up the the fiberglass around the crack which came off fairly easy. Then I realized the extent of the rotten wood which went kind of far. After seeing how thick the wood + fiberglass were, I just broke out the power saw and started going to town. Now I've got a 4 foot square hole in the floor (It goes side to side and it's all in the back). And I found that not only the floor was rotten, but so are the supports that go widthwise underneath. Is there a name for these? I was able to salvage one half (2' long) of one the supports to give me a template of the curve of the bottom. And even though I'm debating if I should just redo the half of the floor I've torn up so far or just go for the whole thing, I'm leaning towards I'd like to just redo the whole floor so that I know there isn't rotten wood underneath.

    Now for my questions.

    As I said I have half a piece of the frame part that goes widthwise, and it has a curve to fit along the bottom of the hull. Is the curve generally the same shape along the whole hull? These pieces are 20" apart, and there are six of them along the 10' of the floor. Can I just make one piece 4' long with this curve and then just duplicate it five more time. Of course the ones near the front will tapper down to about 3' wide.

    Next, how bad is it that I'm doing this with the boat in the trailer? I don't know how much the shape flexes vs when it's in the water. Either way I don't know if I have much choice with this. If I knew were would be the right places I could put other support underneath to shift the weight though.

    So now I need to know what type of wood to use? So far I've been told about marine plywood. Is it better to have the frame parts made from plywood rather than just a 2x4? I've found on a website sheets of marine plywood. Although there were different types, I saw one that was about $100 for a 4'x8'x1/2" sheet and about $170 for 5'x10'x1/2". So here's the plan I came up with. My floor is 10' long and 4' wide at it's widest. I'm thinking I'll get a sheet of 5x10. I figure it'd be a little more stable to have one piece for that 10' long. The frame pieces underneath are currently 1" thick. so I was thinking with the 1'x10' scrap I could cut 12 of all these pieces (they're only 2 1/2" high) then join two pieces of 1/2" together to make it 1" thick. I'll have to do some fanagling to efficiently use the scrap for all the pieces). I was thinking I'd screw the two pieces together with some stainless steel screws. Anybody think that's a reasonable plan? Or if you think it's a bad idea please let me know.

    Fiberglass and epoxy:
    So then how do I seal this? I was told to I'll have to get fiberglass and epoxy. Looking on, I see different types of fiberglass. I'm thinking this looks like it may be what I need. Any suggestions? I haven't looked much into the different types of epoxy yet.

    Putting it all together:
    So here's my plan for putting it all together. I'll first put the 1" thick supports in. Currently, there are fiberglass braces holding them in place. I'll mimic that. Either I can rip out the old braces. Which makes me nervous because they're attached right to the hull. So I'll not want to be too aggressive so that I don't tear into the actual hull. I'll put the cloth in, and epoxy that. Does this really hold them that well? Or can I use the existing braces, slide the supports in and screw them to the existing flaps of fiberglass?

    Then I'll put down the plywood for the floor. My biggest concern here is getting it to join well against the wall. And especially that this seems a likely place that will flex that receive a lot of stress. But I figure I'll apply the fiberglass cloth and the epoxy a few inches up along the side. Is there anything I should be paying attention to here?

    Finally I'll sand and paint the floor. And have a beer while admiring my work. My next step will be repaint the top half, but I'll leave that for a different thread. By the way, here's a picture of the boat Thanks in advance for any of your help.

    Until then,
  2. JR-Shine
    Joined: May 2004
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    Location: Vero Beach, FL

    JR-Shine SHINE

    Hi James,

    A picture of the repair area would be a big help. The fiberglass you link to is chopped mat, its a good filler, but offers relatively little strength compared to biaxial glass. If you want, our designer can look at any pictures of the repair and make a recommendation. We sell all the materials you would need to do the job - and we match or beat all advertised prices.

    Joel Shine
  3. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    You have a classic type of repair(s) for a chopper boat built in this era.

    First of all the shape of the hull DOES change, every inch of the way from bow to stern, so a simple step and repeat kind of thing for the floor supports (floors) repair can't be done. The typical method is to make templates from cheap stock (I use door skin material and 1/4" lauan) The floor (decking) is called the sole.

    A one piece sole is a good idea, but not really necessary if the epoxy and 'glass work is done properly. Over size ply is rather expensive.

    The first thing you need to do is get the rotten stuff out of the boat. The jig saw, circular saw, saws-all, Roto-Zip and router will be your friends during this phase.

    Your trailer doesn't offer a lot of good support for a hull weakened by the removal of a lot of the structure, so thinking about getting her on the hard (in a cradle) should be your next step, though I've seen it done while still on the trailer, it's not how I do it.

    Yank the motor off the transom (which is likely rotten too) this will lighten her a bunch. Wheel the boat and trailer under a big tree limb and rig a chain fall and straps to lift her clear of the trailer. A big come-a-long can do it, but I don't trust the cheap, Wal-Mart bought, stamped steel ones so common to a home owner, so I'd rent a chain fall (hoist) The weight will be on the title or registration, double that and use it as a guide for the hoisting gear. With the engine off and striped of her gear, some big necked friends a few cases of beer can get it done, but you'll have to lift her twice, once off the trailer, then again onto the cradle, hence the need for more then one case of beer (big guys need lots of beer, trust me, I've done this before)

    While the boat is dangling in space, floating above where the trailer use to live, set up several blocks (wood NOT concrete block) along the centerline of the boat and some additional blocking to shore up the turn of the bilge area (two or three on each side will do) Try hard to make the boat sit level on the blocking, even a little bow high so water can drain out of the transom.

    Now the boat is safe, can drain and you can beat, hack and cuss your way to the next stage. Demolition is fun in most things, except when working with 'glass. Get some painter's overalls made of Tyvek, some good rubber gloves and some masks, this stuff will make you itch like no bodies business and it ain't no good to breath either.

    Get the de-laminated 'glass and rotten wood out of the boat, by what ever means you need. When you have a shell of a boat you can then start replacing the structure. Once opened up, you'll have fore and aft pieces (stringers), athwartship pieces (floors), and likely engine bearers or transom knees, below what was once the sole. This structure serves to hold the shape of the boat and transmit the loads through the hull. These pieces will be attached to the hull with 'glass "tabbing" (little strips of 'glass tape - gluing the structural piece to the hull) These will likely be okay, but need "dressing" to be reattached to new structural pieces.

    These structural items will be made in one or more of several methods. Sometimes the builder uses solid lumber or plywood, or foam, or hollow tubes to form this stuff. determine what method they used and do the same with new material. All this is re-tabbed to the hull using the old tabs or grinding them off and making new ones.

    Then a new sole can be installed, by fastening down the ply, tabbing it in and 'glassing it over. Paint and carpet will hide a host of sins committed during the reconstruction process, so don't be to fussy about how it finishes out under the sole.

    This is going to take a while and I've given just a quick over view of what you're up against. Give us a yell (you'll be doing a bunch of that during the process, yelling that is) when you get a better look at the structure. Also check the transom, by sticking your finger or screwdriver in the bolt holes that held the motor on. If they are "punky" or wet, or if the transom flexes as you lift the bottom of the motor, it's done and it will need addressing too.

    You've taken on a big project (there was a reason it was so cheap) but it can be done, but you'll be cussing at it for a while. Don't be scared, you can stop crying now, just take your time, THINK about what you've got to do, BEFORE you start mixing goo or hacking with a saws-all. Take lots of pictures (so it will go back together as it was before) trust me you will not remember everything and be rather grateful for those pictures later. Post some of those pictures and let us know where you're at and how it's going from time to time.

    Good Luck,
  4. jsass
    Joined: Jun 2004
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    Location: Boston, MA

    jsass New Member

    Ok, I've come up with a better plan to get the boat out of the trailer, and I've deleted the old plan so as to not confuse anyone. Anyways, I'm going to pick up the plywood for the floors and sole Friday or Saturday morning. But I'd like a suggestion between two choices. -> Products -> Marine Plywood

    Should I get the Okoume A/B BS1088 or the Douglas Fir A/B? I see that the the Okoume is ligher and has more plys and the Fir will be knotty. When I think about though, I'm fixing a 35 year old boat. If I get 5 years out of this, great. 10 and I'll consider it bonus. I'm not too too concerned about the resell as I only paid $100 for this as is. But I also like to use the better quality product when possible.

    What I plan to buy is:
    For the sole:
    4'x8'x3/4" $139.00 or $78.00
    4'x2'x3/4" $54.00 or $29.00
    For the floors:
    4'x2'x1" $58.00 or $38.00

    That's $251 vs $145. If I felt that extra $100 will really make a difference I'd have no problem going for it. But I've still got a ton of other costs. The fiberglass and epoxy, primer, paint, sandpaper. Plus the paint job for the top half and a tune up on the motor. And then there's the registration, the hitch, oh, and the side panels on the inside. Lifejackets, fishingrods, and a case (or cases) of beer.

    Well, I'm not tring to sound stingy with the dough, but what do you guys think?


    Attached Files:

  5. jsass
    Joined: Jun 2004
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    Location: Boston, MA

    jsass New Member

    So I've been working on a plan for what I need (or what I think I need) to do. This is what I got so far. I know this probably isn't complete. It's just something I whipped up after all the reading I've been doing. Please let me know what what you think. Feel free to offer any suggestions for better detail or anything I'm maybe missing.

    Thanks again!

    1. Get boat off of the trailer and support under keel and edges.

    2. Make cardboard template of sole where it narrows at the front.

    3. Rip out old sole and floors.
    3a. Save floors for template of side to side hull curve whenever possible.
    3b. Sand 3-4" along the inside wall of the hull above where the sole meets the wall to get a better grip with new fiberglass.

    4. Cut new floors.
    4a. Trace from saved floors and/or fit against hull.
    4b. Will make cardboard templates first to fit with the curve of the hull.
    4c. Will be made from 1" thick marine plywood.

    5. Replace floors.
    5a. Coat floors with epoxy.
    5b. Exiting floors are supported with fiberglass tabs that only go half way up along the floor. Sand outside of tabs for a better grip for fiberglass.
    5c. Fit new floors into existing tabs.
    5d. Cover with fiberglass to go up one side along one tab, over the top of the floor, and down along the tab on the other side.
    5e. Coat with epoxy.

    6. Cut new sole.
    6a. 4' wide for the back 8 feet, use template for the curve at the front 2 feet (total 10 feet long).
    6b. To be made from 3/4" marine plywood.

    7. Replace sole.
    7a. Coat epoxy on the underside and around the edges.
    7b. Set in boat and secure sole to floors.
    7c. Put strips of fiberglass and apply epoxy around the edge where the sole meets the hull. Repeat for 3 layers.
    7d. Fiberglass and epoxy the rest of the sole.

    8. Sand, prime, and paint sole.
  6. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Now you're getting the idea, a plan, and it sound pretty good to me.

    1 - Supporting the boat properly makes for a safe place to get things done. I've had them fall off poorly designed supports, so make it solid.

    2 - Templates are a good thing, quite old school. I've found that cardboard, be it corrugated or heavy board stock, doesn't layout as well as using cheap door skin or 1/4" lauan. It should, being sheet goods, but for some reason it doesn't, but you can make it work, I just don't like the stuff, though it is a bit easier to cut.

    3b - Grinding back the edges is good, think 6" for good tabbing.

    4c - 1" stock for the floors seems big. Use what was there or the next fractional size up if you think you should.

    5b - Use better tabbing then they did. It will not hurt anything and will be stronger. Go all the way up . . .

    6b - Again, the sole for your boat is likely made from 5/8" stock. You don't need the extra weight, or cost.

    7c - Cut strips of differing widths, the widest being the first to go down. This builds "bulk" at the turn, but will taper down to a single layer at the edges.

    Epoxy coating the Doug. fur, without cloth in the matrix will not prevent the wood from checking (developing cracks, something Doug, fur is known for) A light layer of cloth over all exposed areas of this plywood will do a much better job of it.

    The Doug. fir is the choice, as it's less costly and it will be buried under goo, cloth and carpet.

    Make sure there are plenty of "weep" holes allowing water that may get below to drain aft to the transom hole. Make sure you don't have areas that you've created that will trap water and hold it against a floor or frame or something.

    Weight is the enemy of all small craft. Extra weight kills small boat performance and can cause the trim to be way off (bow down or stern down when afloat) This is why you should stick with the sizes of materials used originally.
  7. jsass
    Joined: Jun 2004
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    Location: Boston, MA

    jsass New Member

    Actually the existing floor's are 1". But when I messured the thickness of the existing sole I may have been including the layer of fiberglass too. So yeah, the existing one probably is only 5/8". Also, I'm going to count the plys the in existing wood to help me decide between Douglas Fir or Okoume. Although I'm already leaning towards the DF.

    Lemme change two steps...
    5a. Coat floors with polyurethane.
    7a. Coat polyurethane on the underside and around the edges.

    But as in 7d, Fiberglass and epoxy the rest of the sole, I was planning on putting fiberglass on the whole top side. Is fiberglass what you mean by cloth? Or are you implying to put fiberglass on both sides?

    Ahh... makes a little case to pick the Okoume to save a few pounds.

  8. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 476, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Polyester doesn't stick to wood well at all. To save some bucks on goo you could coat the wood products with epoxy, then use polyester to build bulk and tab things in, though there is a strength penalty in doing that. I would strongly recommend you not do it that way. Your boat may have been built that way, but the jury was still out on how well the process would work. The jury is in and it don't stick a lick to wood of any type. Epoxy does.

    When we speak of 'glass work we are talking about a matrix of catalyzed or activated resin entombing cloth/mat/roving or other material. The cured resin alone has little strength. This is true of both polyester and epoxies. The cloth/mat/roving in the matrix is what gives it it's strength and other properties we want. It's an engineered material and must be dealt with in that fashion, only. You can't have too much or too little of any part for it to work well.

    You can easly use the Doug. fur and it will serve well for the tasks you have. Skip the costly stuff.

    Cloth is one of many reinforcing materials used in the matrix. Cloth is a woven material, much like a bed sheet, but made with glass (just like the thing drinks get served in) it can also be had as a mat (chopped fibers loosely held together) and many other materials, each having different properties for the differing application requirements.

    Log on to for a real education by the industry leader in the field of epoxy, epoxy applications and related products and testing. They will be happy to send you (free) information on the products, the processes/procedures, how to work with the products and how to handle some of the issues you're looking at now.

    There are occasions when you will use epoxy without the reinforcing material, but it will be part of a process to build a laminate which will likely have some reinforcing material added, but may not necessarily be cloth, it could be something like aluminum oxide (the grit used in sand paper) or microscopic spheres of glass or wood dust (yes, the stuff under your table saw, but much finer) or strands of carbon. The list is quite long . . .
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