plywood floor
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=13223
Printed Date: November-17-2024 at 2:00pm
Topic: plywood floor
Posted By: ryanowen
Subject: plywood floor
Date Posted: April-03-2009 at 2:35pm
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From reading through some different threads on flooring, it seems that some have gone with a plywood floor instead of glass on foam. For those that went this route, what did you do to secure the floor?
Thanks, Ryan ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Replies:
Posted By: Tim D
Date Posted: April-03-2009 at 2:41pm
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Stainless screws (brass break too easy) and silicon on the seams. I used 3/4 treated (salt) and put 7 or 8 coats of polyurethane on the top and edges. ------------- Tim D |
Posted By: 8122pbrainard
Date Posted: April-03-2009 at 3:22pm
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Ryan,
Ideally you should be able to get by without any fasteners. The ply should be set into a thickened epoxy on top of your stringers. Weights can be used to hold it in place while the epoxy sets up. The bond will far exceed anything you would get from screws. If you do want to screw it down, I even recommend using the screws temporarilly and then removing them after the epoxy sets. Then filling the holes. If you want to leave the screws in place, here's some recommendations. Stainless if it does get wet and stays wet will rust!!! Brass isn't the best choice ether because although short term it will work, brass long term "zincifies" - the zinc in the copper leaches out and all the strengh is lost. Boat builders have learned from many years of experience that http://www.jamestowndistributors.com/userportal/search.do?freeText=silicon%20bronze%20screws&page=GRID&history=7czuob11%7Cother%7CfreeText%7Esilica+bronze+screws%5Epage%7EGRID%5Euser_att_name0%7EUserType%5Euser_att_value0%7ENewUser - silicon bronze screws are the best to use. If you do go with these screws, be carefull - the "frearson" head is NOT a "phillips" head. You need to use a frearson driver bit. Use regular exterior ply with the CPES and epoxy. Do not use treated ply as any coating and the chemicals in the treated don't mix well! Many will contest to problems - With our members, I know Eric had some disasters!!! If you have any gaps that need to be filled, stick with filled epoxy. We know it will stick whereas silicon caulking won't! If you do caulk, use 3M 5200. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: WakeSlayer
Date Posted: April-03-2009 at 4:05pm
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I used 3/4" exterior ply. I put 4 coats of epoxy on it. I used the peanut butter on the bow and sides of the motor. I used stainless screws to remove any little bows and make certain it was tight on the stringers. I thought about removing them, but just left them in and filled the tops of the holes with epoxy. On the rear sections, i just screwed them down with stainless in case I ever had to get at the exhaust hoses. (They run outboard of the stringers on the Mustang)
FWIW, the screws from the original longitudinals were brass and still intact when I did the teardown. Mike ------------- Mike N 1968 Mustang |
Posted By: WakeSlayer
Date Posted: April-03-2009 at 4:06pm
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Do not use silicon.
I believe I am quoting Pete here: "Silicon won't even stick to itself" ------------- Mike N 1968 Mustang |
Posted By: ryanowen
Date Posted: April-03-2009 at 4:38pm
Thanks for the responses guys. I'm in the info gathering stage right now, and from where I'm starting from, that might take a while. 
Hopefully this isn't too stupid of a question... but why not make a floor that's completely removable? Wouldn't that give things a chance to dry out each season? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Posted By: 8122pbrainard
Date Posted: April-03-2009 at 5:05pm
Ryan, If you follow the CPES, epoxy and care when you glass up the wood, water moisture won't get into the wood. Keeping it out is the key. Once it gets in, it doesn't like to dry out even after extended storage. The wood is like a sponge wrapped up in a plastic bag. Edit: Any holes (like engine lags) drilled into the wood post stringer job need to be CPES'd and I recommend 5200'd when you run the fastener in. Mike, I'd say that those screws you removed in your 68 were silicon bronze and not brass! Aged it turns a slightly darker or browner color than brass. I'd also say they were Frearson heads. If you tried a phillips, I'll bet it didn't fit very well. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
ryanowen wrote:Posted By: ryanowen
Date Posted: April-03-2009 at 6:20pm
I guess I'm worried about my ability to keep it out though. If I permanently glass in a floor and water gets beneath it through seat bases or hairline cracks or some other means, I can never get it back out again. Trapped water seems to a common theme with these rotten floors. If I could open up the floor periodically, things could dry out a bit. Plus if pool noodles didn't work out, you could switch things up! 
Just thinking out loud. What would the downside to a removable floor be? ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Posted By: ryanowen
Date Posted: April-03-2009 at 6:33pm
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Here's an observation that got me thinking. Although I haven't pulled the floor up yet, I think it's safe to say the wood glassed beneath the drivers seat base is rotten. The 20 year old (untreated?) removable piece of plywood behind the motor is in remarkably good shape though. One of the back corners was starting to go, but I think that could have been prevented if the seat base had been removed every once in a while. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Posted By: SNobsessed
Date Posted: April-03-2009 at 6:34pm
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I am not a design engineer, but I have stayed at Holiday Inn Express lately. I would think you will lose some rigidity if you just screwed the ply floor down. Plus the screw holes in the stringers would be a water intrusion point. How do you attach it to the hull sides? Would you glass wood strips to screw into? ------------- “Beer is proof that God loves us and wants us to be happy.” Ben Franklin |
Posted By: ryanowen
Date Posted: April-03-2009 at 6:43pm
Me neither. I was wondering about rigidity too. I don't know what part the floor plays with the overall structure of the boat. The screw holes are definitely a consideration. I'm not sure if cpes in them would be sufficient or not. As far as atttaching the sides? Not sure. Again, just thinking out loud. Maybe glass pieces of wood or a long strip. Kind of like the way the swim platform backings are. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Posted By: WakeSlayer
Date Posted: April-04-2009 at 12:01am
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I epoxied my screw holes also.
I did not glass my floor down. I epoxied several blocks down the sides level at the bottom of the floor. The floor just sits on them however and is not fastened to the little support blocks, just the stringers. My floor is not removeable at all, but in the event of an exhaust failure I could slit the carpet and get the side boards from there back up without too much trouble. The plan is to never have to do so. I installed my side carpet before I put the floor down. I feel it gives it a cleaner look as you have a pretty tight to work with there. One other thing that has not been mentioned is that you defnitely want to have some drain holes in your stringers to let any accumulated water out. A lot of factors went into how I did what I did. Take everything you learn from everyone here and decide which pieces of the puzzle suit you best and get after it. It is actually a pretty fun job except for the grinding BS. ------------- Mike N 1968 Mustang |
Posted By: WakeSlayer
Date Posted: April-04-2009 at 12:14am
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Pete, Funny you say that about the screws. Some came out with the phillips and some I ended up just drilling out after the head failed. I am guessing you are right about the material as the coloring you described is exactly right. I will look to see if there is an errant one left under the workbench of something. I would like to know. ------------- Mike N 1968 Mustang |
Posted By: nautiless
Date Posted: April-04-2009 at 5:32am
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Ryan:
With WakeSlayer on this one. I'm busy doing a resto myself. Not to repeat Wake's layup of the floor....but rather to add another member who's gone with this floor set up. ------------- 1982 SN 2001 RIP (Resto in Progress) http://www.correctcraftfan.com/diaries/details.asp?ID=4400 - Don's Diary |
Posted By: Fl Inboards
Date Posted: April-04-2009 at 11:26am
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Here is what I use when I re-floor inboards,
http://www.coosacomposites.com/ Check out the web site see for your self. This stuff is a little more expensive than good marine ply. I have had really great results with this material, Current Correct Crafts have this as floor boards behind the motor box. Word of warning though Coosa does not hold screws well, needs to be thru bolted when ever fastening is required. Jody ------------- Hobby Boats can be expensive when the hobbyist is limited on their own skill and expertise. 1993 Shamrock "fat" 20. 2008 Nautique 196 5.0 |
Posted By: 8122pbrainard
Date Posted: April-04-2009 at 11:37am
Mike, Here's a picture showing the head differences between the Frearson and Phillips. I think the picture on the Frearson is slightly off and the slots shown are a little narrow. The key difference is no radius on the inside of the cross intersection and the angle of the tip is different. 
The Frearson (also called Reed and Prince) was designed as a anti cam out solution to the Phillips. Going back into the history of wood boats, the plain slotted screw was first used but needed to be driven with great care. If not, and you slipped while fastening down a piece of deck hardware lots of damage was done to a nice varnished mahogany deck. Next came the Phillips answer but to make it easier to make in the cold heading process, the inside corners were radiused and each "wing" of the tip was beveled (relief). The cam out problem still existed especially with a worn screw driver bit. The Frearson was developed without angles and radius giving it max grip. They caught on in the boat industry and were exclusively used by many until the early 70's. Using a Phillips driver on chromed Frearson deck hardware fasteners is quite damaging! Every once in awhile, I'll see the "newbee" mistake at shows on wood and some early glass. BTW, Jamestown distributors http://www.jamestowndistributors.com/userportal/show_product.do?pid=447&familyName=Frearson+Driver+Bits - Frearson bits has them. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: April-04-2009 at 11:56am
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you forgot the good ole hammer and nail Pete ------------- "the things you own will start to own you" |
Posted By: 8122pbrainard
Date Posted: April-04-2009 at 12:00pm
Sorry Eric!! Silicon Bronze - Threaded Annular Ring Nails Also known as Bronze Boat Nails or Silicon Bronze Ring Shank Nails.   ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: eric lavine
Date Posted: April-04-2009 at 12:03pm
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do you know who Hank Hill is? ------------- "the things you own will start to own you" |
Posted By: eric lavine
Date Posted: April-04-2009 at 12:18pm
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He is a cartoon guy on TV, he was taking his wife out on a date, he was excited and to look good he said....Peg, get out the lazer level I need to shave my sideburns
watch the show sometime ------------- "the things you own will start to own you" |
Posted By: ryanowen
Date Posted: April-04-2009 at 1:01pm
And here I am just worried about my boat being able to float when I'm done with it!  ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Posted By: ryanowen
Date Posted: April-04-2009 at 1:10pm
Do you have any pics of this? That's kind of what I was thinking about.
We'll see about that! ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Posted By: ryanowen
Date Posted: April-04-2009 at 1:18pm
Jody, Thanks for the link. Very cool material. Is it any harder to work with aside from having to through-bolt? I'll have to see if it's available here. I'm curious about the price. Ryan ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Posted By: 8122pbrainard
Date Posted: April-04-2009 at 6:03pm
Ryan, JoeiNY did his stringers and floor in coosa. There's quite a long and very detailed thread on it. It's nice stuff but is is on the expensive side. Joe tells all about it. ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: WakeSlayer
Date Posted: April-04-2009 at 6:13pm
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Pete, I am certain you are right about what screws were in the Mustang. Wish I could find one to be 100%, but just by looking I think they were Frearsons. Weird. Never heard of them.
Ryan, I looked at all my project pics and cannot find any of the little support blocks. They are just 3" x 3" or so pieces of 1x left over from my secondaries. Nothing special at all. Just fit them tight under the longitudinals or floorboard, or better yet, both. Really, after you are done, you will look back and think it was a really cool undertaking, and will be surprised with how good it turned out. I was scared shi!tless beforehand. Afterwards, I was happy I did it, and can hardly wait to do another next winter. But the grinding does suck. Bad. Mike ------------- Mike N 1968 Mustang |
Posted By: JDiggs
Date Posted: April-08-2009 at 4:34pm
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Did you guys have any seams in the floor?
Im going to use plywood, but Im going to span the plywood perpindicular to the length of the boat instead of parallel. Im doing this for strength reasons, Im not going to put any cross pieces in so I want the plywood to span between the stringers rather than from front to back. What did you guys do to seal the seams in the plywood or what should I do? Glue them together w/ epoxy sounds like the best option |
Posted By: 8122pbrainard
Date Posted: April-08-2009 at 4:40pm
JD, If you really want to get fancy, you could scarf them! Don't forget the http://www.jamestowndistributors.com/userportal/search.do?freeText=cpes&page=GRID&history= - CPES ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: WakeSlayer
Date Posted: April-08-2009 at 4:43pm
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I ran my ply perpidicular also. I was able to get the whole floor done with two pieces. I did the first seam with just epoxy thickened with fairing filler. The second I left alone so in case I ever had to get at my exhaust it would not be the end of the world.
As far as cross pieces, what do you mean? ------------- Mike N 1968 Mustang |
Posted By: BuffaloBFN
Date Posted: April-08-2009 at 4:47pm
Geeze Pete?!!? LOL Mix some microballons in some epoxy and fill away.  ------------- http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold "It's a Livin' Thing...What a Terrible Thing to Lose" ELO |
Posted By: 8122pbrainard
Date Posted: April-08-2009 at 5:44pm
Greg, Remember all the talk about you putting down a clear floor to show off all your woodworking skills? Knowing you, if you did a ply floor, It sure wouldn't surprise me if you scarfed it!!! ------------- /diaries/details.asp?ID=1622" rel="nofollow - 54 Atom /diaries/details.asp?ID=2179" rel="nofollow - 77 Tique 64 X55 Dunphy Keep it original, Pete < |
Posted By: JDiggs
Date Posted: April-08-2009 at 7:12pm
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Pete,
Scarfing isn't in my carpentry dictionary at this point. I will attach a 1x4 cross piece at this point only to support the joint. Im referring to the 1x3 pieces between the main and secondary stringers as the cross pieces. Basically Im being lazy and don't want to notch the stringers for them, plus they are redundant if you span the plywood cross ways. The only way they would be required is if cantilevered out to pick up an edge support for the floor at the hull. When attached, the plywood provides continuous lateral bracing of the tension face of the stringers (when the stringers are loaded from the water side), which I feel makes the stringer system as strong or stronger than the original foam and fiberglass system around the stringers. The plywood provides greater floor diaphragm strength than the fiberglass (basically it's a stiffer floor) When the stringers are loaded from the top by people and the motor, then the hull braces the tension face of the stringer laterally. Same as the original design in this case. Anyway, that's my thoughts on the plywood floor from a stringer structure standpoint. Unless Im missing the way the boat sees the forces. |
Posted By: BuffaloBFN
Date Posted: April-08-2009 at 7:17pm
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Pete, you're too much. Alan posted the dovetails a while back...and I sure haven't posted any scarf joints!
I would learn to make that joint someday if I had a really good reason...but...I picture a sizable guillotine type cutter for this! ------------- http://correctcraftfan.com/diaries/details.asp?ID=2331&sort=&pagenum=12&yrstart=1986&yrend=1990" rel="nofollow - 1988 BFN-sold "It's a Livin' Thing...What a Terrible Thing to Lose" ELO |
Posted By: ryanowen
Date Posted: April-09-2009 at 10:37pm
Doesn't the hull provide support on both the top side and bottom side of the stringer due to the fiberglass wrap over the top? I definitely think your method would be stronger than factory either way though. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=3284 - 1988 Ski Nautique |
Posted By: JDiggs
Date Posted: April-10-2009 at 5:35am
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I said that backwards. The stringer needs no lateral bracing on the tension face. Lateral bracing of the compressive face increases the beam strength against buckling failure. A beam or column will never "buckle" under a tension load.
Either way, its braced on the bottom by the hull and at the top by the floor. The fiberglass on the stringer at the top makes it stronger in the weak direction, but doesn't brace it. I consider it braced only if the bracing object is much stronger/stiffer than the object being braced. Im not sure it matters either way, Im sure something else would break before the stringers fail that way. IMO the stringer system is stronger when a plywood floor is used in lieu of a foam floor. However, I think that foam makes the hull sturdier and stronger. Im a structural engineer, therefore I see everyhting in free body diagrams and moment and shear diagrams. I can't help it. |
Posted By: eric lavine
Date Posted: April-10-2009 at 11:56am
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the discussions have always been about rot, not boats snapping in half, I think the hulls have the strength built in and the stringer systems adds to an already strong hull ------------- "the things you own will start to own you" |