Boat False Floor Progress

[BaitThrower]

Just adding a piccie of my False floor project for my oldish 4.3m SeaJay.
Went with treated pine idea suggested by a few others on this site as no welding involved and reasonably inexpensive.

Here is the frame all done. Just have to add a few securing blocks here and there.

Just got the 12mm Exterior ply sheets today. Will seal them then screw them down which should further increase rigidity.

Then marine carpet is going on top.

[dogsbody]

Looking good there BT. Does the frame need some sort of sealing?

Dave

[385EXPLORER]

looks tidy mate well done,geez she's solid,not too heavy eh?

[Breambuster33]

looks sweet so far
cant wait to see the finished project
good luck;D

[foxx510]

Looks like a solid job. If you want to save some weight, I'd consider removing a fair bit of timber from the rounded cross supports that sit in the ribs. The ply only needs a little support due to it's inherent stiffness.

[BaitThrower]

looks tidy mate well done,geez she's solid,not too heavy eh?

Not really... I probably could have weight all the pieces but I think maybe only 10-15kg all up in the frame material.

[BaitThrower]

Looking good there BT. Does the frame need some sort of sealing?

Dave

Apparently not? It's CCA treated (bloody poisonous stuff) that apparently can sit in the ground and get wet lots and not rot... so I wouldn't think so. Hopefully its not going to be continuously submerged in the bottom of my boat :P

I will be sealing the plywood floor though.

[BaitThrower]

Looks like a solid job. If you want to save some weight, I'd consider removing a fair bit of timber from the rounded cross supports that sit in the ribs. The ply only needs a little support due to it's inherent stiffness.

Hmm thats got me thinking... I could drill out a few holes in those and still maintain most of the stability... like an aircraft wing frame eh? I might just do that... Maybe three or so 2" diameter holes in each piece running across the beam to reduce weight... Good thinking!

Edit: Although, on the other hand... Drilling the holes would expose more of the timber in the heart of each piece... Could potentially lead to more water intrusion in each piece and more potential for rot (or fast decay).

[BaitThrower]

looks sweet so far
cant wait to see the finished project
good luck;D

Will post more pics as I go :)

Just trying to figure out what sort of console to put in, and where... Have a switch panel to mount for the lights and an Eagle sounder to put in... Thinking of building just a plywood box and securing it somewhere in the middle of the floor... kinda like a centre console but not as glamorous... This would hold the battery and switch box and associated wires etc and give a place to mount the sounder...

Or I could mount everything at the side somewhere in another little box.... Don't know yet... Still looking for ideas and pics for this... So if anyone has any, send them through!

Not paying mega-bucks for a pre-made console thats for sure! Not when I can build one :)

[foxx510]

Not really... I probably could have weight all the pieces but I think maybe only 10-15kg all up in the frame material.

I'd seriously look at reducing that. If it's rotproof timber, then yep drill a heap of big holes in it, it will still be strong as(and look really cool!) As a comparison, the aluminium frame that supports the floor in our tinny would weigh less than 2kg easily. You really don't need much, the ply is so stiff. I don't want to sound like I'm having a go at your work though, it's clearly beautifully built. You can probably get away with a thinner sheet of ply though with all that support.

[JayT]

Top shelf work mate,
Didnt consider say a 50ltr or plus under floor tank...?
always more deck space:)
Cheers

[CreelReaper]

Top job mate, did you notch all the timbers and seal where they meet??? I agree with Foxx510, I reckon you would be able to get away with a 6 or 8mm ply to top it off. With the spacings you've got there won't be any sag.

Shane

[fez]

BT,

Good job, very neat.

With the CCA timber I thought that once it is cut then the timber is no longer protected. The process of dipping the timber in the CCA it only is drawn into the timber in the layers closest to the outside of the timber. Once it is cut this compromises the intergity of the timber. Not 100% sure but may be worth checking out whist you still have the oppertunity to seal the timber if required.

Cheers,
fez

[stevej]

max depth we can treat to is 25mm and we sell almost 300 cubic meters of pine per month

CCA-treated timber is timber preserved with Copper Chrome Arsenate (CCA) or Chromated Copper Arsenate, as it is known in some countries. The copper (23-25%) and arsenic (30-37%) in CCA act as fungicides and insecticides, while the chromium (38-45%) fixes the chemicals into the wood (APVMA, 2003e; Greaves 2003). The chemical mixture is injected into the wood under pressure so that the wood is saturated with the chemicals.

wouldnt the copper react with the aluminium ? the product leaches for months after treatment

[juju]

It may be worth your while coating the cut (or for that matter all of the timber) with one of these products..
http://www.mabonstimberprotect.com.au/products.html
They make timber presertives, treated pine will still warp and cup when it gets wet (eg treated pine pailings...notice how many go wonky)...they make a product called cellivet (think thats the spelling) that puts a coating preventing moisture getting into the timber...great stuff....i come across heaps of treated pine that still stuffs up...this stuff stops that...not too many $$ either...

[sleepygreg]

A question about the treated pine. What Hazard level is it claimed to be treated to? For constant water immersion it needs to be at least H5-6. A Sleeper is treated to H4....but that is for in ground contact, not immersion. The timbers that you look to have used are those that you would buy at Bunnings or equivalent that would be treated to H3 at best. Definitely not suitable for the purpose you have in mind. And being a 'dry' timber they will readily absorb water, which means they will leach their treatment, it wont be enough to cause probs with the reaction with the alloy (ffs their is more naturally occurring chemicals in the foods we eat than their is in a metre of treated timber), but the longevity of the timber will be severely reduced.

A word of caution to all people who are doing underfloor mods/construction on boats.....DO NOT USE KD Treated pine...it is just not suitable. How do I know....I sell the stuff for a living and have done for 30 years. Have lost count of the number of inspections I have attended due to product failure, only to find that the product used was clearly unsuitable for the job.

I wouldnt be worried about the copper in the treatment, i would be worried about the Hot Dipped Gal screws that are essential to fix correctly treated pine to the crossmembers. (will eat through aluminium real quick).

Greg

[sleepygreg]

Sorry guys. Didnt mean to denigrate the great carpentry job done, looks bloody fantastic. But I also dont want to see a post on here in twelve months time asking how to repair my rotted underfloor frame, and 'what action can i take against the jerk that sold me the timber'.

Greg

[BaitThrower]

I'd seriously look at reducing that. If it's rotproof timber, then yep drill a heap of big holes in it, it will still be strong as(and look really cool!) As a comparison, the aluminium frame that supports the floor in our tinny would weigh less than 2kg easily. You really don't need much, the ply is so stiff. I don't want to sound like I'm having a go at your work though, it's clearly beautifully built. You can probably get away with a thinner sheet of ply though with all that support.

Well the gaps are still quite sizeable really. The picture probably a little misleading.. i.e. my foot still easily fits between all the gaps with room to spare, hence why I went or am going with 12mm ply... Anything less seems to flexible for those larger spans. I'd rather over-engineer a little than under-engineer. I drill out some of the bulk timber around the keel line though to reduce weight.
:)

[BaitThrower]

Top shelf work mate,
Didnt consider say a 50ltr or plus under floor tank...?
always more deck space:)
Cheers

Would be nice but A) can't afford that at moment, and B) wife would kill me if i even mentioned it ::)

Only got a 30HP on it so will just carry a 22ltr tank with an 8ltr backup can up front for reserve. Should do me fine for most outings. Was thinking I should utilise the space in there somehow for something... Maybe a bit further down the track... This project is really just a basic, inexpensive floor upgrade for now to get me through the next couple years until I go the whole hog and probably convert the boat to forward steer and get proper frame floor with underfloor tank etc.

[BaitThrower]

Top job mate, did you notch all the timbers and seal where they meet??? I agree with Foxx510, I reckon you would be able to get away with a 6 or 8mm ply to top it off. With the spacings you've got there won't be any sag.

Shane

Nope not yet... Its just sitting in there at the moment so nothing is permanent, but after reading the other replies here, looks like I definitely need to get some decent sealer on everything!

[BaitThrower]

max depth we can treat to is 25mm and we sell almost 300 cubic meters of pine per month

CCA-treated timber is timber preserved with Copper Chrome Arsenate (CCA) or Chromated Copper Arsenate, as it is known in some countries. The copper (23-25%) and arsenic (30-37%) in CCA act as fungicides and insecticides, while the chromium (38-45%) fixes the chemicals into the wood (APVMA, 2003e; Greaves 2003). The chemical mixture is injected into the wood under pressure so that the wood is saturated with the chemicals.

wouldnt the copper react with the aluminium ? the product leaches for months after treatment

What about pressure treated timber? I was under the impression, or read somewhere that the treatment is forced all the way into the wood under pressure? Not that I have got that timber it seems :(

[BaitThrower]

A question about the treated pine. What Hazard level is it claimed to be treated to? For constant water immersion it needs to be at least H5-6. A Sleeper is treated to H4....but that is for in ground contact, not immersion. The timbers that you look to have used are those that you would buy at Bunnings or equivalent that would be treated to H3 at best. Definitely not suitable for the purpose you have in mind. And being a 'dry' timber they will readily absorb water, which means they will leach their treatment, it wont be enough to cause probs with the reaction with the alloy (ffs their is more naturally occurring chemicals in the foods we eat than their is in a metre of treated timber), but the longevity of the timber will be severely reduced.

A word of caution to all people who are doing underfloor mods/construction on boats.....DO NOT USE KD Treated pine...it is just not suitable. How do I know....I sell the stuff for a living and have done for 30 years. Have lost count of the number of inspections I have attended due to product failure, only to find that the product used was clearly unsuitable for the job.

I wouldnt be worried about the copper in the treatment, i would be worried about the Hot Dipped Gal screws that are essential to fix correctly treated pine to the crossmembers. (will eat through aluminium real quick).

Greg

Greg, Thanks fore the info mate... Yes I think it is H3 rated. I am pretty sure actually. Hmm so where to from here... Can I still use it and seal it with a good timber sealer? I don't expect this floor to be last me 20 years... I'd be happy with 3-4 years :) Hopefully I can get that out of it.

Can I use stainless screws to fix the timber together? None of the stainless screws would be in contact with the ally hull directly... only into the wood...

[BaitThrower]

Sorry guys. Didnt mean to denigrate the great carpentry job done, looks bloody fantastic. But I also dont want to see a post on here in twelve months time asking how to repair my rotted underfloor frame, and 'what action can i take against the jerk that sold me the timber'.

Greg

Fair call... Looks like I should have done a bit more homework to start with, although I only had a small budget to work with too, otherwise it wouldnt get done at all. Hopefully a good timber treatment will help seal everything and buy me a few years of use?

[oldboot]

looks good... very similar to what I have done.

I went with 18mm luan/ meranti......I dont regret the weight....i did weigh it all and it came out to about 45Kg all up, I made the frames out of ply too.

regardles of the timber you have used you need to seal it, the cca treatment will only protect the timber from mould and insect infestation.....the water alone will have a variety of effects on the timber.

If I was doing it again I would assemble with marine epoxy and no fasteners and seal with the same.....the modern epoxies are specificaly designed for this.

Otherwise.....go with several coats of thinned varnish or uncoat so thet it real gets in.

I secured my frames in with BIG cable ties thru holes bored in the frames and under the aluminium frames....It pulled up rock solid....It would want to with 16 BIG cable ties.....I bedded the frames on self adhesive velcro loop ( the fixzzy part) tape... because I have the stuff.....I was thinking about rubber or roadcase carpet...but the loop tape was easy and cheap for me.

I used the spaces in the frames to block in some styro flotation that I cut to size on the band saw....I managed to get about 130Kg of extra flotation under the floor ( that the flotation value not the weight)

The floor sheet I scribed in on each side and it just sits there with a couple of cleats holding it down front and rear.

I put more fuzzy velcro tape allong the tops of the frames to stop squeeks and stuff......I used self adhesive rubber feet on the sides of the floor sheet to buffer off the sides.

the front and rear securing cleats go full width across the thwarts and have more rubber feet on the bottom where the meet the sheet to prevent squeeks and to allow drainage.

I am realy happy with the way it came up....solid as and drains very well....and the gaps are too small to allow a 00 sinker to fall thru.

I'll try and dig up the photos.

cheers

[BaitThrower]

looks good... very similar to what I have done.

I went with 18mm luan/ meranti......I dont regret the weight....i did weigh it all and it came out to about 45Kg all up, I made the frames out of ply too.

regardles of the timber you have used you need to seal it, the cca treatment will only protect the timber from mould and insect infestation.....the water alone will have a variety of effects on the timber.

If I was doing it again I would assemble with marine epoxy and no fasteners and seal with the same.....the modern epoxies are specificaly designed for this.

Otherwise.....go with several coats of thinned varnish or uncoat so thet it real gets in.

I secured my frames in with BIG cable ties thru holes bored in the frames and under the aluminium frames....It pulled up rock solid....It would want to with 16 BIG cable ties.....I bedded the frames on self adhesive velcro loop ( the fixzzy part) tape... because I have the stuff.....I was thinking about rubber or roadcase carpet...but the loop tape was easy and cheap for me.

I used the spaces in the frames to block in some styro flotation that I cut to size on the band saw....I managed to get about 130Kg of extra flotation under the floor ( that the flotation value not the weight)

The floor sheet I scribed in on each side and it just sits there with a couple of cleats holding it down front and rear.

I put more fuzzy velcro tape allong the tops of the frames to stop squeeks and stuff......I used self adhesive rubber feet on the sides of the floor sheet to buffer off the sides.

the front and rear securing cleats go full width across the thwarts and have more rubber feet on the bottom where the meet the sheet to prevent squeeks and to allow drainage.

I am realy happy with the way it came up....solid as and drains very well....and the gaps are too small to allow a 00 sinker to fall thru.

I'll try and dig up the photos.

cheers

Thanks mate some good tips there. I havent considered squeaking issues yet but I guess I will now... Was thinking of maybe trying to wrap the carpet over the edges of the plywood against the boat sides to prevent this, but not sure if this would be easy to do, or if the carpet has that sharp bendable properties to do this cleanly...

Yes please send through pics when you get a chance. Would love to see them.

[sleepygreg]

BaitThrower, I would be using the best sealer i could get hold of and going over ALL of the timberwork AFTER it has been finished. Stainless Steel is a good idea for fixing the timber, but unnecessary if it is totally sealed and not into the aluminium. Sorry I didnt see your original post when planning this, as I could have advised you on a number of better timbers to use that did not require this treatment. Once you cut pressure treated CCA KD pine...the warranty is effectively voided. Pressure treating (which is how it is done to H3 standard) does NOT penetrate to the centre of the timber...and that is if it it done to ASA standards....which unfortunately a lot are not. The standard to be adhered to also requires the timber to be appropriately sealed and coated....ie...not left in its original state. Which means YOU have to make sure you seal it properly and make sure all joins/fixings are within specs.

By all means use the construction adhesives that are now available....most of the brand names are bloody great...the bond will be stronger than the timber they are bonding to. As for the ply....the glues used in upper level plys are the same as the ones used in Marine ply, the difference is Marine ply does not have gaps in its inner layers (that is if it is manufactured to ASA/NZ specs), It still requires sealing, especially on the edges.

Greg

[BaitThrower]

It may be worth your while coating the cut (or for that matter all of the timber) with one of these products..
http://www.mabonstimberprotect.com.au/products.html
They make timber presertives, treated pine will still warp and cup when it gets wet (eg treated pine pailings...notice how many go wonky)...they make a product called cellivet (think thats the spelling) that puts a coating preventing moisture getting into the timber...great stuff....i come across heaps of treated pine that still stuffs up...this stuff stops that...not too many $$ either...

Looks like "Cellavit Green" is the way to go for treating and protecting the timber frame yes? Where does one buy this stuff?

[BaitThrower]

BaitThrower, I would be using the best sealer i could get hold of and going over ALL of the timberwork AFTER it has been finished. Stainless Steel is a good idea for fixing the timber, but unnecessary if it is totally sealed and not into the aluminium. Sorry I didnt see your original post when planning this, as I could have advised you on a number of better timbers to use that did not require this treatment. Once you cut pressure treated CCA KD pine...the warranty is effectively voided. Pressure treating (which is how it is done to H3 standard) does NOT penetrate to the centre of the timber...and that is if it it done to ASA standards....which unfortunately a lot are not. The standard to be adhered to also requires the timber to be appropriately sealed and coated....ie...not left in its original state. Which means YOU have to make sure you seal it properly and make sure all joins/fixings are within specs.

By all means use the construction adhesives that are now available....most of the brand names are bloody great...the bond will be stronger than the timber they are bonding to. As for the ply....the glues used in upper level plys are the same as the ones used in Marine ply, the difference is Marine ply does not have gaps in its inner layers (that is if it is manufactured to ASA/NZ specs), It still requires sealing, especially on the edges.

Greg

Ok so maybe I'll join fix all timbers together with construction adhesive... At present they are a tight fit so kinda holding themselves together anyway but some construction adhesive should make sure it is rock solid...

After that I'll seal everything, perhaps with "Cellavit Green"? and give it all several coats, including the ply floor and fix it all down, then add the carpet on top (using whatever glue or non-glue method) that will work with the cellavit coating on the plywood...

The floor will be easily removable so I can recoat with cellavit after 24 months, then hopefully that lasta another 24 months at which time I should have enough dollars to do the floor with welded ally supports when I convert the boat to forward steer etc etc :-/
Sound like a good plan?

[oldboot]

Personaly I would be avoiding carpet over ply in an exposed position.

I don't know the celavit product.....

The main issue with ply ( to start with) is not rotting, it is the opening of the grain and cracking of the finish.

Almost all ply is laid up from rotary cut veneers... as such it is full of microscopic cracks......if it is not adequately sealed the water gets into these cracks and causes the top laminate to det full of micro warps, which opens up the grain further.

I've played with plenty of ply and carpet over the years and left quite a bit of it out in the eliments.

As far as timber treatment.....for get everything that the building industry tells you and have a look at some of the marine industry information.

The frame realy isnt the big concern because it will not be exposed and will be out of the water ( mostly). The deck surface is real what you want to think about.

it is gong to cop the weather and the salt water.

I'd be going with some for of texture / traction finish.....that is what I have done I an am glad I did.

As for con struction adhesive.......I have never been a real fan of it for joinery.......Lots of people underestimate good old PVA or even better some of the better grades of PVA ( the alaphalactic resins for those who want to know....yellow PVA).......even ordinary PVA has very good water resistance if not immersed or exposed......the yellow stuff is even better.

Epoxy is definitely the best option, I was introduced to mraine epoxy about 2 years ago... and DAMN it is good stuff.......

If you must carpet... still think it is a bad idea over wood...... depending on the carpet what you can expect.........if you are using the lighter carpets there should be no problem bending it arround a 12mm edge.... but don't expect the glue to hold it, unless you have at least a 100mm overlap on the other side....then you have issues with cutting in your corners.

If you are looking at "DECORD" or the similar heavy ribbed carpets... forget it.......for a 90deg corner youneed to allow the thinckness of the material as a bending allowance.....that stuff is about 6mm thick so wrapping a 12mm sheet will be hard work.....it can be done... but you may have to beat it into submission with a block to get it to sit tight.

One other issue with carpet.....if you are planning to put it down with contact cement.....sprayable / brushable is normal.....there are adhesion problems with contact over paint....it does not stick well.

have a look over at woodworkforums .com. there are some good threads in the wooden boat section that cover some of these issues.......be carefull thought you might get hooked and want to build something.
I think I have some pictures over there..... but I am someone else there;D

OH... when dealing with sealing ply..... go after the end grain very agressivly......
for every surface coat on ply I do two on the end grain.......so one coat each side means 4 on the endgrain......

cheers

[BaitThrower]

Good info there oldboot!

What about this epoxy sealer? http://www.norglass.com.au/cgi-bin/frontcart/frontcart.pl?command=details&itemid=3

Looks alright!

Yeah I am a member over at the woodwork forums myself :-)

[sandbankmagnet]

Looks wery neat. What would it take to make some little in-floor compartments in the spaces in the frame. Some look big enough to hold a decent sized box of lures, or flares and v sheet etc.

[BaitThrower]

Looks wery neat. What would it take to make some little in-floor compartments in the spaces in the frame. Some look big enough to hold a decent sized box of lures, or flares and v sheet etc.

Probably not a lot :P Would have to make custom boxes though as I didnt really measure them to any specific size... But yes a lot of potential wasted space there true...

Project at the moment is just to get the floor done as quickly and painlessly as possible so I can actually start using the boat! ::)

[oldboot]

I am aware of both norglass and epidure.....there are sections of the wodden boat community that are very fond of either or both.

most of the blokes I talk to are more in favour of either "west system" or "boatkote". both of these products come as a two part unfilled resin product and you prepare it by adding fillers and additives to produce a range of things from a varnish like product thru to a heavy bog like product.

I've been using west system, mostly as a glue...... but next time I will probaly swing over to boatkote...... both are made in aust...west under licence by ATL composites..... and boatkote is an australian formulation made and marketed by boatcraft pacific at loganholme.

I know that carbatec and glasscraft stock west system.

It all depends on how fussy you are and how deep your pockets are.....many will say that epoxy coating your frame and deck sheet is overkill........and they may be right.......but this stuff is for keeps.

normal mortals would be happy with a realy proper 2 or three coats of good quality thinned paint....

cheers

[jerson]

Bait Thrower,
You may need to isolate the treated timber from the alum ribs, it may react, all fixings in CCA need to be galvinised when used on land. Neat work!

[oldboot]

A good coat of paint or other sealer should solve the CCA corrosion issues.

cheers

[Crestcutter]

Mate are you putting a center console in? If so now might be the time too think about how you are going to run your cables. Mine run through holes and pop out the back underfloor. I used a length of pvc so that cables etc could be replaced if need be.

[BaitThrower]

Floor is now in...

What I did was used two coats of epoxy sealer on the timber framing, followed by 2 coats of marine paint...

Did the same on the plywood floorboards, with all edges sealed with at least 4 coats of epoxy sealer and 2 coats of paint :)

Marine carpet on top (not fixed down yet though).

[Noiseworks]

How is the rest of the project going BaitThrower? Keen to see some photos and a quick update.


Cheers
Noiseworks