rot in J B wilds Caribbean

[MBA Marine]

hi mark

 i,m puzzled as to your advice about "fill up the outboard edge" sorry i dont understand. I was just going to fiberglass in the floor supports and lay plywood with underside painted with epoxy paint? need i do more?

The hull gently curves up from the keel/bilge area heading outboard, water drains down this curve to collect in the bilge but where stringers run for and aft water can collect on the outboard side of them. If you fill up the area the water holds in then the water has no obstruction but all original strength is retained.

I would use a resin with a powder additive to make a paste to fill areas and then encapsulate that with a thin layer of GRP. 

[MBA Marine]

The hull gently curves up from the keel/bilge area heading outboard, water drains down this curve to collect in the bilge but where stringers run for and aft water can collect on the outboard side of them. If you fill up the area the water holds in then the water has no obstruction but all original strength is retained.

I would use a resin with a powder additive to make a paste to fill areas and then encapsulate that with a thin layer of GRP. 

Having looked at the pic that Strowger has flipped over I cant see any of the area's that I was suggesting to fill, still its good advice if you do find a water trap! 

Another vote here for dont put the foam back, allow air to flow under the floors, if you want to insulate then staple some of that foil covered bubble wrap stylee stuff (technical term!) tightly on top of the bearers before fixing your board down, this will keep the air space clear below.

[Oddfellow]

Do not attach insulation directly to any surface if you can avoid it.

 

Doing so will cause condensation and/or other moisture to be trapped. You should always have an airgap between such things to allow moisture to be carried away.

[raga]

thanks again folks.

 i have removed all foam and stringer/beams. it was soaked. Not a chance of it drying out! the foam actually prevented any chance of pumping bilge dry.

 i spoke to a guy who replaced floor on his caribbean, he said there was no foam at all in his hull. Where some build without foam?.

 Can I get away with not fibreglassing in the floor supports? A friend has suggested this, just bond down supports with mastic, lay plywood floor and bond it to old remaining fibreglass?

 

[raga]

Quite convoluted turning the photo up the right way after they've been posted. (The forum software handling of images doesn't allow copy to clipboard or save. )

 

 

Thank God for fibreglass hulls though. Despite the decay in the internal floor, the boat hull itself is quite sound, and still very practical to restore.

 

 

I wouldn't double up on the 18mm ply myself, I would rather glass in additional new bulkheads halfway between the existing ones.  Cheaper and much more rigid....

thank you for sorting out pic. i dont know what went wrong!  and thanks for advice.

 could i get away with using gripfill to bond supports to hull and not fibreglass in?

[Guest]

...... could i get away with using gripfill to bond supports to hull and not fibreglass in?

 

 

I have to admit that I have no professional boat building background, but if it were my boat, I would definitely epoxy the new underfloor bulkheads to the boat's hull moulding.

 

I would regard the bulkheads as part of the hull structure, rather than just a spacer to support the floor up from the bottom.

 

Although the very flat bottom to the hull makes them quite slender, they do give some support to the almost flat fibreglass hull at that point. That's why the originals were glassed in, as part of the original glassfibre layup when the hull was moulded.

 

If you can get the inside surface of the glassfibre scrupulously clean, then roughen the area with sandpaper to get a good key, then clean with acetone to remove any grease, the new plywood will bond on very strongly, with epoxy resin, rather than polyester resin.

 

Your remedial work will then strengthen the hull, as well as support the new floor.

 

I would also carefully leave semicircular "mouseholes" at regular spacing along the bottom edge of each bulkhead to allow any trapped condensation/water to run through between each section to the lowest point where a bilge pump can remove it rather than getting trapped in each section.

[650xs]

she look like like a gem good ole boot i say .....

 

is she the one at thames or bristol ...????

 

is staying there or coming hum .......????

[Oddfellow]

I wonder if the foam was put in later to act as a secondary support for a sagging floor? Stranger things have been done.

 

Any limber holes that are drilled in the bilges must be sealed with something to stop the drain water from entering the wood.

 

You absolutely must properly bond the new flour supports to the hull with GRP. Failure to do this will be a total loss of ridigity which threatens the structure of the vessel.

 

Bonding two bits of 18mm marine ply together to form new bearers is probably the way to do this. Use an epoxy resin for the bonding.

[MBA Marine]

 

"If you can get the inside surface of the glassfibre scrupulously clean, then roughen the area with sandpaper to get a good key, then clean with acetone to remove any grease, the new plywood will bond on very strongly, with epoxy resin, rather than polyester resin."

 

 

 

 

Gotta disagree, epoxy does not bond well to polyester and visa versa dont get me wrong it does stick well but not bond as one, you would want Vinelesta this bonds to either, but you will not go wrong just using Polly resin, but its how you use it that matters, prep like Strowger suggests but one step further would be to clean with styreen, make sure your matt is fully emulsified but not flooded with resin, dont just use a paint brush, fluffy 4" roller and a metal paddle roller.

 

Dont use No Nails, do it properly if your going to do it, and resin wash or bilge paint the underside and edges of your board before you put them down.

[Oddfellow]

Good advice from Mark there.

 

I'd go further; if there's any consideration that there may be dry rot present (it's highly likely), then you should seal ALL exposed edges to stop the fungus from finding a new food source. In fact, I would really recommend treating all new ply properly with wood preservative that kills dry rot becore you bond it.

 

There are no short cuts in this job. You simply do not want to have to do this again in a few years time.

[raga]

she look like like a gem good ole boot i say .....

 

is she the one at thames or bristol ...????

 

is staying there or coming hum .......????

hi 650xa

 she is in Bristol and has been here about 20, or more year. hasnt been in the water for about 10yr

[raga]

Thanks for further advice .

 i will be fiberglassng floor supports in, as the concensious says this is a must.

some people have removed bulkheads to make their Caribebean open plan. are not the bulkheads needed for structrial integrity? I will be keeping bulkheads.

 should I bond floor to remaing fiberglass floor close to bulkheads?

[raga]

 

 

Also if you can store your timber in a dry area, as you don't want to build in more damp!

Replacing your floors is not as difficult as may first seem. make sure the bulkhead bottoms are sound and still bonded to the hull, if not remove the old GRP and re-glass them in (replace bulkhead if its rotten) then work out from there 

you will have fairly small stringers running fore & aft rather than drilling holes in them to let water through them, fill up the outboard edge so that water runs over them, then you will most likely only have the off centre companionway bulkhead to limber through, and as Clive has said, seal around the holes.

 

Hi mark.

 bulkheads were only bonded to fiberglass floor, so restore to that? A friend who is helping to lay floor says dont fiberglass supports to hull, but i,m not sure this is good advice. his reasoning been its a river boat not sea going, so not under the same stress,s.

if I bond supports in, and if the boat is twisted on its props, would the bonded supports pop off?

[Oddfellow]

They might move a little if moved, but unless the boat is supported really badly, they shouldn't tear. All the real weight should be on the keel with the side supports being more for ballance than weight distribution.

 

Without that ridigity, it might be damaged during lifting or slipping; the fact that it's a riverboat and not sea-going really is not the issue.

[Guest]

.........I'd go further; if there's any consideration that there may be dry rot present (it's highly likely), then you should seal ALL exposed edges to stop the fungus from finding a new food source. In fact, I would really recommend treating all new ply properly with wood preservative that kills dry rot becore you bond it.......

 

 

Modern wood preservatives that soak into the surface and end grain do a good job at preventing rot from starting or spreading.

 

Likewise, coating clean, dry new timber with epoxy resin completely seals the wood against water ingress.

 

One needs to be very wary of using both methods on the same wood though, since the epoxy won't bond properly to treated wood until it has thoroughly dried out, over many weeks or even months.

 

With any new wood going in, I would just stay with just epoxy resin. It is a very versatile product which can be used as a clear coating on its own, or as a filler paste when mixed with "Microballoons" or "Colloidal Silica", or as a very strong joining material with glass mat or woven tape.  Some people criticise epoxy resin for giving poor results, but when used correctly, following the instructions exactly, it gives the strongest bond of all, coupled with the highest water imperviousness.

 

It's easy to misuse, like not getting the mixing ratio exactly right, or trying to "wet out" galssfibre mat with the wrong binder. The temporary binder in glassfibre mat is specific for either polyester resin or epoxy resin, and using the wrong type will prevent the binder dissolving and allowing the resin to penetrate the strands and bind into a solid mass.

 

I would disagree with the assertion that polyester resin bonds better than epoxy resin to old fibreglass. As long as the surfaces are surgically clean, epoxy is a superior bonding agent to almost any material, and is the least water permeable when cured.

 

When filling redundant skin fitting holes in GRP hulls for instance, professional advice is to use epoxy resin, silica, and tape or mat.  Polyester would have produced a much weaker plug, with much weaker bonding to the grp hull.

[raga]

Good advice from Mark there.

 

I'd go further; if there's any consideration that there may be dry rot present (it's highly likely), then you should seal ALL exposed edges to stop the fungus from finding a new food source. In fact, I would really recommend treating all new ply properly with wood preservative that kills dry rot becore you bond it.

 

There are no short cuts in this job. You simply do not want to have to do this again in a few years time.

friend has  suggested  I fiberglass  in stringers  along lenght  of boat , but use mastic on cross  beams . he suggest s  fiberglassing them in 6  months or so ,as to allow boat to settle in to shape . any opinion  on this?

[raga]

hi again .

anyone any suggestions as to matting /resin I should use?

[MBA Marine]

hi again .

anyone any suggestions as to matting /resin I should use?

You will get differing opinions but if I was doing the job, I would use 3x 600g (2 0z) chop strand mat overlapping the joints with each layer and polyester resin.

But its all in the preparation, I would take a grinder with a course sanding disk to the hull to remove any dirt, paint ect, leaving the surface well keyed up, vaccume and then clean with acetone, also slash your ply with a knife (FINGERS!!) where the mat is to me applied.

 

If you are a total novice here you could well get in a very sticky mess so hone your skill on something small, its not difficult to 'mat bash' but looking at many peoples efforts it would seem easy to get wrong, better resin rich than to dry but best if you remove any excess resin (best way is to scrape your fluffy roller on the lip of your resin bucket to remove resin from roller then roll back over the resin to draw off the excess)

 

Good luck and if you dont have enough ventilation your eyes will look like this     afterwards!

 

As for the 6 month thing, it cant hurt if you have 6 months, but not a luxury that most would have!

[Oddfellow]

Get the right tools and safety equipment.

 

Recommend 4 inch fluffy rollers for applying resin (short handle roller frames) and cheap, disposable brushes too.

 

Get a couple of paddle rollers to consolidate the GRP layers and pull the resin through. If you use a brush for this, you will probably end up stippling the mat too much and start pulling it apart which ruins the integrity of it.

 

Buy a 5 litre can of Acetone and have a number of containers to hand (that won't melt) for cleaning tools. Put the paddle rollers in the acetone when you are done with them else the resin will set and the roller will be useless.

 

Get a couple of buckets for resin.

 

Get some disposable overalls, the blue 3M ones are very good. Paper ones are pretty crap. Disposable gloves too. Nitrle are good for resin.

 

Remember, in cold conditions, resin will not go off. You need at least 5 degrees C for it to cure. So, a fan heater for the compartment would be a good idea, or a radiant heater is useful too as this can warm the area rather than the air.

 

You can't be too prepared for this!

[Guest]

Good advice there from John and Andy.

 

I'd emphasize the point about temperature though, and I wouldn't try laying up grp below 10 degrees c.

 

If you carefully follow the instructions, measure and mix accurately, and are surgically clean with the old surfaces being bonded too, it does a really good job.

 

"Tupperware" is much maligned by many boating purists, but it's a great building material for lasting with minimal or zero upkeep.

 

I did my garage flat roof with it last Summer, with a huge £600 DIY kit with 10 gallons of resin and a huge roll of CSM glass mat.

 

It turned out quite well, and should last 30 years or so....

 

 

[MBA Marine]

I must have missed Johns advice!

[raga]

You will get differing opinions but if I was doing the job, I would use 3x 600g (2 0z) chop strand mat overlapping the joints with each layer and polyester resin.

But its all in the preparation, I would take a grinder with a course sanding disk to the hull to remove any dirt, paint ect, leaving the surface well keyed up, vaccume and then clean with acetone, also slash your ply with a knife (FINGERS!!) where the mat is to me applied.

 

If you are a total novice here you could well get in a very sticky mess so hone your skill on something small, its not difficult to 'mat bash' but looking at many peoples efforts it would seem easy to get wrong, better resin rich than to dry but best if you remove any excess resin (best way is to scrape your fluffy roller on the lip of your resin bucket to remove resin from roller then roll back over the resin to draw off the excess)

 

Good luck and if you dont have enough ventilation your eyes will look like this     afterwards!

 

As for the 6 month thing, it cant hurt if you have 6 months, but not a luxury that most would have!

hi Mark. he did of course mean six months after it was put in the water. He feels the boat has been standing for so long,that if i glass the cross beams in, when e lift the Caribbean it might well twist and cause some damage. I would like to finish fiberglassinng as soon as possible! But my concern is if I DONT glass cross beams in ,but use mastic to bond them to hull, will they be strong enough when boat is lifted?

I,m a novce at fiberglassing, my last 2 attemps were so so, but i shall be extra caredul this time!

[Guest]

I must have missed Johns advice!

 

 

My apologies Mark,  yes,  I should have said "Mark and Andy".

 

If only my brain could keep up with my typing.....  

[MBA Marine]

hi Mark. he did of course mean six months after it was put in the water. He feels the boat has been standing for so long,that if i glass the cross beams in, when e lift the Caribbean it might well twist and cause some damage. I would like to finish fiberglassinng as soon as possible! But my concern is if I DONT glass cross beams in ,but use mastic to bond them to hull, will they be strong enough when boat is lifted?

I,m a novce at fiberglassing, my last 2 attemps were so so, but i shall be extra caredul this time!

I would just glass them in, I cant see it coming to any harm if its propped properly, if it was not propped up properly then its probably a funny shape by now any way and its not going to just go back how it should be because its in the water.

 

Ask yourself can you look at it and see its out of shape? I doubt it, and if it is but you cant see it then why worry, its a bath tub built for comfort not for speed unlike a car when the tracking is out your not going to notice it pulling one way or the other!

 

There is a chance if you just stick them in then when she is picked up they could well fall out

 

of cause in my humblest of opinion!

[Oddfellow]

It's a real difficult call. Glass in now and risk strengthening a twist or risk a lift into the water and glass there once settled. I wouldn't like to advise on this.

 

Whatever you do, make sure that you can see what's happening. So, if you glass in now, don't put the floors in so when she's splashed, you can check of for any cracking.

 

We're making a new roof for one of our fleet boats currently. The old one was ply and is rotten as a peach in places. Take a look on our facebook page for progress reports: www.FaceBook.com/FreedomCruisers.