appologies Gary,

I certainly didn't mean that carbon boats don't have a great 'life expectancy' in comparison to the timber boats, care and maintainance of either goes one hell of a long way to the life we can expect from either, we've all no-doubt seen timber mozzies in a almost non-recoverable condition due soley to being parked out in the weather for years on end..... neglected !! .... Twice Shy was certainly a borderline boat, wreck or restore was a tough decision at the time, I'm glad I made the right choice

The full carbon parts I have here are all sun damaged and much like the neglected timber mozzies, all have been "left out in the yard" with no care taken what so ever to protect them from the ravages of the weather.

I honestly have no idea as to how long a full carbon boat would stand up to being left parked out in the weather without any form of care or without being maintained in any manor.... hence my query as to will a full carbon boat last 5 years let alone 40 years, I seriously don't know.....

Carbon composites such as carbon kevlar etc as you have said are doing well at the 20yearish mark, I guess we have to wait and see how a pure carbon hull does do, hopefully they too will still be around in 40 years time too, not that it will do me any good, I'll be in my 90's

main deck area gutted.... almost





inwhales removed along with the original hull stiffeners...
New replacement inwhales just the right of the hull

really gutted now ...... or is it

The rear deck surface is under no real downward load, so I think I will side with the boatbuilder on this one.

After removing the 2 ply plates, you are going to add stringers, beef up the area where you have just removed the support and if you do as you have with your boat, going to add glass as well?

I'm not trying to be smart, but I did read overkill there somewhere..

Hi Kingy .
Your making some great progress there. It would be interesting to know the weight of just the shell, are you going to weight them and before you replace old for new will you weigh the new foam, ply and other materials.

I'm very much interested to see how close you can get to 55kgs.

See I'd argue if the rear section needs such a stiffener to prevent a foot cracking the hull then why aren't there several more of them down the main deck area as well ???
That and the fact that the plate was only a couple of inches from a major structural support tends to make me think you'd want to be fairly accurate on exactly where you put that foot on that screaming reach...
I'd also argue if, as your suggesting, "The rear deck surface is under no real downward load" then why did the original plate extend out under the deck as far as it did down the hull side ???

further more for downward load on the deck..... where do your hands go when your clearing a lump of seaweed from the rudder or trying to un-jam a stuck rudder blade, on the rear deck obviously, but only where the ply plate was which in reality is just behind the alloy beam, you couldn't place a hand any further back because it offers zero support from there back.




The 2 plates are long gone along with the crazy amount of resin they'd been glued in with, resin must have been dirt cheap back then going by the amount that's been liberally applied throughout the boat, the weight or the 2 WRC (western red cedar) 10x14 stringers, the small piece of 40gsm cloth and the 2 WRC tags I'll glue in for the foot strap screws wont weigh as much as the ply plates and chunky resin that was there..... I'll also gain deck strength for when that heavy mit is placed on it.

As I said earlier, I'd have retained the plate IF it had of been further back towards the transom, this would have increased the foot supporting area and better assisted the rear deck aswell.... hell I'd have left it there if it had of atleast made the front edge of the hatch hole but to be only a couple of inches back from the rear beam there's just no advantage for it at all.


Always good to see how others think that a particular thing should work, I'm not always right but I try and make the best of a structural **** without going overboard, I can clearly see where your thinking is and I do to an extent agree with the ply plate design, just not its original location .... had it have been 6" from the back beam it would still be there and with a 2" lightening hole through the guts !!

As for the weight we've removed....

so far one and a half wheelie bins
of that 5 vacuum cleaner bags (and counting) of cwrapy rubbish from years gone by


oh..... & that wheelie bin load doesn't include the old foams, they're still floating around in the shed ..... bonfire time ??


Our aim is to get it as close as possible to the 65kg region, and as a guideline she was way over that to start with.

I glued in the new inwahles tonight and the teardown is now 99% done, its just about assembly time for all the new stuff....
as for an exact weight, might scale it tomorrow night for ya

For the record two blokes could lift the fully rigged platform
With a bit of grunting (a lot) haha
Considering how heavy it was i still managed to
Be reasonably competitive at local level.

FYI Kingy.
Rear inspection ports on 1827 are offset (to the outer gunwale) with a single central stringer (12mm x 10mm), in the vertical orientation. I inserted 5" ports compared to 4" on 1765. I ensured there was sufficient space between the gunwale and the stringer as the latter was fitted. With the larger holes and their offset the ease of access is incredible. I have no issue with trapping on the transom, even with the inspection ports' location. Trust Photos tell the story.



The extra ply ring is planed flattish, thinned to zero in the middle, to reduce the curvature impacted on the plastic ring and improves tightening,sealing and removal.



Main beam inspection port, offset also.

its still on a very strict diet, more weight came out tonight and there's more to shed

half a wheelie bin got put out tonight & I still have the timber mains decks, the internal stiffeners, and the foams in the shed....

you do ofcourse know this means you'll need to shed as much as the boat does....

Just being fair here

Love the idea Phillip, even less weight with that design

but I'm a bit old school and being in the construction game I like things symmetrical, so I don't know if I could visually except the offset hatches.
Yeah I know ->

As I see your design the actual hatch is a structural component in itself, the side load on the hull is being pushed not only through the deck ring but through the plastic cover aswell... The plastic hatch ring and cover are far stronger then the ply that supports it so yes its structurally very strong across the actual deck line.

This is where the secret lies for lightweight structural strength, its a matter of spreading the load in the right direction, but more importantly knowing which way the load is being sent so it can be correctly dispersed

Phill (Al's dad) and I have had several long conversations on how we should tackle each situation, we're actually way ahead of ourselves at the moment but we're solving each issue fairly easily & way before we need to.
We hit a bit of a wall tonight regarding the way the stringers are to be set in with what we want to achieve (mind you the foams aren't ready to go in yet), but now I've had a coffee and the house is quiet I think I have a whole new plan, Phill's gunna be peaved



The reason I do these threads is mainly for feed back on what I'm doing or thinking but to collectively share different ideas on how to best tackle a design that's light but strong, hopefully others can use the ideas they see from not only me but form others like yourself that add vital info

cheers for that

To share more info. Two stringers in foredeck, 3 in main deck. As previous 1 in rear deck. All 12 x 10 in the vertical. Foam b/heads have a 10mm topping, glued and filleted to the gunwale, glued only onto the foam, no fillet. Ply frames have 1 'topping' glued to the side of the ply. Study photos.






I shaped the deck curve into the toppings, then ran a 10mm router bit through them to cut the housings for the stringers. Set up a 'straight edge' for this operation, finished in 20 minutes, all sections, both hulls. Stringers dropped down into their housings to the correct level, no levelling required except for minimal sanding with a torture board.




The photos show breather holes at the top of the frames, particularly for the foredecks' foams. My experience is the moisture condenses under the decks and airflow is improved if gaps for flow is up where the moisture is. Bottom moisture flows out through the limber holes and can be sponged out, the condensation remains.
Another reason for moving the holes up to the deck, I discovered the polystyrene foam lost it side strength with holes in their centre and they flexed in when compressed; and when one considers these forward foam bulkheads are there to stop the hull sides flexing and pumping. I have found the forward flat sections of the hull much stiffer on 1827 than 1765.
On foam; closed cell polystyrene foam is better then open celled rigid polyurethane. A coat of epoxy (It is compatible) will seal the styrene and with it being closed cell and sealed, will not take up moisture. Urethane will only seal with a layer of glass and the resin as with the foam sandwich hulls.
I used 'medium density' polystyrene foam, 25mm thick, light being too soft (popular with sign writers), high being too heavy.
Always willing to share my thoughts and experiences.

Many thanks for the pics, some really interesting work and thought has gone into that build and the end result looks fantastic.....

Agree fully on the condensation issue, it's certainly a major part of the deck failure as we've all witnessed with TwiceShy's decks.
Any water in the hulls turns to a vapour and condensates on the highest point.. the decks... With the older build styles, the decks weren't sealed in any manor so the moisture attacked the timber decks from the inside, this in turn softened the ply and more importantly around the glassed areas where the foam supports sit, this then allows a small amount of movement of the deck / foam joint....
Once the decks move a little bit the foam is allowed to come under more load and slowly begins to compress under a sailors weight, the decks also move downwards which pushes the hull sides apart during this time, and that then places the strain on the foam to hull side connection, that's where the foam fails and the hull sides now move in and out slightly, this in-turn lets the decks come down even further crushing the foam even more as it goes and again the foam breaks it's contact with the hull sides further down....

It eventually gets to the point where nearly the entire foam / hull connection fails and the foam becomes nothing more than a loose piece of buoyancy hanging around in the hull...
With the foams having failed, the load then goes directly into the stringers and as they are now completely unsupported they now fail rather dramatically by cracking or splintering, once the decks have reached this stage the load then falls directly on the ply and it's life expectancy is very short.... The most noticeable thing at this stage is small splits in the paint work or small bulges in the ply specifically directly under where the beams are mounted.. So if you see a boat with a bulge or cracks in the paint work in that area there's a fair chance the decks are in need of attention.

During this whole process that condensation is working away at the foams and the timber and as each small fracture is opened that moisture makes it's way in further which speeds up the process even more.

With the ply support plates I do and the ones you've put in on top of the foams, the loads are spread out more evenly through the foam so the chance of a foam failure is minimal.

I'm really pleased with the lighter decks I have now, especially the fact that I can put my entire weight into the ball of my foot, stand on the decks and they don't move at all, with the 40gsm cloth glassed in on the underside of the ply the moisture has no starting point with which to start attacking the decks either, the up-side of the classed underside is the added strength for a very minimal weight addition.....

When I lay Scorpian's decks I'll also do a sample of the glassed ply and video it being loaded up, anyone that's seen me demonstrate this has been amazed as to how much strength is achieved....


In years to come others will find even better ways to do what we're doing and with even lighter and stronger materials..... I have so many different ideas I'd love to try out to get the fat off, maybe them old hulls might one day have a thread of their own...

time for some new foams

one set cut and the 2nd set about to be

trial fitting of the new foams

at this stage they are very close to a perfect fit in the hulls, the deck line although hasn't been cut properly so they are in rough-out shape at the moment..

looking forward from the rear beam....



and

looking forward from the front beam



its really not a hard thing to do to get the holes to line up

The 2 foams between the front beam and the case slots have extra long holes cut in them, this allows very easy access to all the bits inside the hulls that may need unbolting etc

and as I said earlier, the keel line cut outs have been increased in size dramatically

ounce by ounce the fat is trimmed

those rotten inwales are long gone and its time for the new ones to be fitted, the question became ..... how ??

at first I thought I'd scarf them in but as you can see....
that wasn't going to happen


the rot had gone much further than I thought

plan B



dug out the old inwale completely from under the beam blocks right down till I had original glass work...

the new inwale gets cut to fin in the recess