DIY front hatch & bulkhead.

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Owen
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DIY front hatch & bulkhead.

Post by Owen » Mon Jul 13, 2009 4:53 pm

I thought some of you might be interested in this.


Following on from the end of this thread.
http://www.ukriversguidebook.co.uk/foru ... 5&start=30

I decided I need to get on and do the front of my Anas Acuta. To find the position of the front hatch. I just took the end of my footpegs added a couple of inches and marked it for the bulkhead then added another eight inches. Then I drew a twelve inch diameter circle and cut a big hole in my kayak.

Image

Also I made a disc in fibre glass about fourteen inches in diameter, I cut the hole in the middle to fit the hatch rim.

Image

And then stuck the two together with Tradeweld (Methylmethacrylate).

Image

Then I made a bulkhead, I pushed the disc and hatch rim as far up the bow as I could and fitted the bulkhead,

Image

Glassing that in was by far the hardest job to do. I very nearly wrote myself off with the fumes. Crawling in through an ocean cockpit to work on that side of the bulkhead was really hard. Getting at the other side wasn't easy either. Next I bolted the disc into place.

Image

And blocked off the back of the gap between the disc and the deck with modelling clay.

Image

Then made up some resin and filler and started building it up in the gap.

Image

Finally I added a coloured flowcoat.

Image

Not the most smooth finish I ever done. Next I need to sort out the deck layout.

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Ceegee
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Re: DIY front hatch & bulkhead.

Post by Ceegee » Mon Jul 13, 2009 10:28 pm

Not as tidy as the rear hatch you did mind! Presumably you could loose the screws now, fill the holes and get to work with a bit of wet'n'dry? Should come up a treat.

Anyhow, looking good so far.

Steve
Cheers,
Steve C. G.

rockhopper
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Re: DIY front hatch & bulkhead.

Post by rockhopper » Wed Jul 15, 2009 1:16 pm

Crikey Owen.. your brave !
I haven't even started to strip off the old paint from one one I got hold of. Just the thought of what I might find underneath gives me the heebi-geebies. I guess fibreglass work is sooner or later going to have to be another skill to add to my quiver !!

I look forward to the next instalment......

Rog.

Owen
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Re: DIY front hatch & bulkhead.

Post by Owen » Wed Jul 15, 2009 2:39 pm

Rog,

What ever is under that paint is there, you'll find out sooner or later, no point in hesitating. Fibre glassing isn't hard, but getting a good finish is proving to be. Just rubbed it down to start again. Some of the terminology can be mind blowing if you need help just ask.

Steve,

I put the bolts in because I wasn't happy glassing to the underside of a very old deck. I had visions of thumping the hatch cover on and everything parting company. With the disc holding the hatch rim and the deck bolted together there shouldn't be to much flexing to break the bond. I intend too glass over the nuts so that they don't rip my dry bags to bits.

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Jim
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Re: DIY front hatch & bulkhead.

Post by Jim » Thu Jul 16, 2009 1:17 pm

That will certainly work, bombproof job!

There is at least one way to get a neater job but it involves making up some intermediate bits (which could be used again in the future), whatever method you use though, there will always be a seam between the old and the new that is difficult to disguise or make invisible.

Just wondering - did you consider making up a 12" dia flexible tube (I'm thinking from mylar or something) that could have been used to push the filler back into a straight vertical wall around the opening and left in until it had cured? It would have been fiddly but might have been feasible - the drawback with that would be that you might create a pond around the hatch, at least with your filleting the recess should drain as the boat rocks from side to side.

Steve,
The rear of the AA is easy because it's flat, you just have to cut the hole and fit the hatch, with the front you have to make a flat area to fit the hatch to :-) Most boats have that issue both ends!

Rog,
Fibreglass skills are not something to be scared of - if you don't want to learn on your boat try making a flat panel first and then practice cutting bits out of it and bodging bits on. To make a flat panel you need a smooth shiny board and some mould release wax, wax the board (follow the instructions on the tin, you need several coats first time), then just make fibreglass directly onto it (with or without gel coat), when set you will need to trim the hairy bit round the edges but you will have a fibreglass panel and an idea of how much oversized you need to make parts to allow for trimming. If you want to join 2 surfaces to make a mould, use modelling clay (or plasticine) to make a radiussed fillet between them (smooth out with your finger), then the part will release, the plasticine will probably be stuck to it but when cleaned off you should have a smoothish rounded corner (if you try to get a sharp corner the glassfibres won't go into it properly so you get a void, and if you do get the fibres into it, it won't release).

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ChrisS
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Re: DIY front hatch & bulkhead.

Post by ChrisS » Sat Jul 18, 2009 11:09 am

Jim

Would it be a viable alternative to bolt a flat disc (same diameter as the rim) to the deck, with spacers where needed to keep it level, then filling the voids at the sides and mounting the rim onto the resulting flat surface?

Chris

Owen
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Re: DIY front hatch & bulkhead.

Post by Owen » Sat Jul 18, 2009 12:17 pm

Chris,

I take it you mean having the hatch above the deck instead of under it. That would work but might look a bit odd.

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ChrisS
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Re: DIY front hatch & bulkhead.

Post by ChrisS » Sat Jul 18, 2009 1:34 pm

Yes, that's what I mean.

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Jim
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Re: DIY front hatch & bulkhead.

Post by Jim » Sat Jul 18, 2009 11:45 pm

Chris, that would be feasible, but like Owen I think it would look a little odd.

The method I prefer (never actually got to try it but was considering it for upgrading an old Nordkapp) is to take a mould off the deck, then build it up much as you describe (building onto the mould surface will create a recess on the moulding), and then take a moulding from that that can be spliced into the deck. Obviously this requires a bigger cut out in the deck but leaves you with straight relatively easy seams to make good. If you make the mould plenty oversize in the first place you can use it as a guide/former to help you get the splice section level with deck.

As I say, I haven't done this with a kayak deck, but I have done something similar with canal cruiser decks - for the shorter boat we used laminate the front and rear portions of the deck from the mould for the longer boat and then splice them together using a short portion of deck mould we had made up. It was never quite invisible, but we did have a diamond non-slip pattern to line up!

The main thing to bear in mind is that you need at least twice the amount of materials compared to Owens method and in engineering terms is no better, just a little neater.

Jim

Owen
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Re: DIY front hatch & bulkhead.

Post by Owen » Sun Jul 19, 2009 4:18 pm

And finally.

Image

The finished hatch.

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Simongelder
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Re: DIY front hatch & bulkhead.

Post by Simongelder » Thu Sep 04, 2014 10:53 pm

I am about to embark on fitting bulkheads, hatches, deck lines etc to an early 1980s Nordkapp HM. Looking at the various other posts I will probably laminate my own bulkheads using CSM and polyester resin. However I would appreciate advice about what to use to glass the bulkheads into the fore and aft of the hull. Should I buy glass tape or have people managed ok by cutting strips of CSM for the join. Previously I have found it messy and difficult to get the wetted out CSM to stay moulded into corners. Perhaps this is because the CSM was too thick and heavy? I will be ordering all materials required afresh rather than compromise with what I happen to have already in my garage.
Thanks in advance for any advice!
Simon

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Jim
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Re: DIY front hatch & bulkhead.

Post by Jim » Fri Sep 05, 2014 1:21 pm

If possible, make the bulkheads with a flange all round (the flange will go on the cockpit side) and use a suitable flexible marine adhesive like Sikaflex 291 (there are cheaper alternatives with the same approvals and no shelf life printed on the cartridges).

If you don't want to use flexible adhesive (really it is better than hard laminating bulkheads in) you will find it a lot easier using tape or strips of woven fabric to fis the bulkheads in place. Each strand of glass fibre is actually thousands of tiny fibres held together in a bunch by a chemical binder, in CSM the same kind of binder is all that holds the mat together. When you wet the mat out the binder dissolves in the resin and helps it penetrate between the fibres so CSM quickly becomes a soggy mush. With tape or cloth, because the strands are woven they retain much more structure when wetted out, which means you can wet them out on the bench and then carefully lift them and place them in the boat. An advantage of tape over strips of cloth is that the weft (or is it the warp?) is continuous backwards and forwards and stitched along the edges to keep it doubled back on itself - if you cut strips of cloth individual strands of both warp and weft can come adrift whilst handling. A disadvantage of SOME tapes is that the edge thread and doubled over continuous strand stops them laying down flat and smooth, which you can do with strips of cloth. I have found no way of telling when I buy a roll of tape if the edges will behave or not!

Lastly, neither CSM or tape not cloth will take a 90 degree sharp bend, there will always be a corner radius, you need to make a fillet first when glassing the bulkhead in (resin + filler powder) or when making a flanged bulkhead use some plasticine to make a smooth fillet between the vertical face and the flange of your mould - plasticine is resin proof and eaisly cleaned off if it sticks to your finished bulkhead, it's what fibreglass moulders use for smoothing joins in moulds (in bulk packs of grey rather than multicoloured)! 1/2" or 12mm radius will be fine, you may get away with less but larger radius is always better. If you don't make a fillet you will get a void (air pocket) under the tape/cloth at the sharp corner and resin will drain out of the weave before it cures leaving it porous.

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Simongelder
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Re: DIY front hatch & bulkhead.

Post by Simongelder » Fri Sep 05, 2014 11:11 pm

Thanks Jim, that helps a great deal.
I am now wrestling with how I would go about making bulkheads with flanges. I figured that I would laminate sheets which are slightly larger than needed and cut to size using a cardboard template taken from the appropriate part of the inside of the hull. To make flanges would you cut to the correct shape than apply the fillet of plasticine around the edges and then the tape/cloth before fitting to hull? If I do this I don't know what to do with the void left after removing the plasticine other than using filler paste.

Think the rear bulkhead(s) will be relatively easy but I am dreading the forward bulkhead. I have an ocean cockpit and even adjusting the footboard is hard work. This could be even worse as I may hold of trying to fit a forward hatch for a while due a combination of the technical difficulty and the fact that I am unlikely to do anything other than day trips for so time yet. It would be slightly easier to get to the bulkheads whilst there are holes for the bulkheads.

I was thinking of fitting either a drain plug on the deck for the front tank or a 10cm screw deck plate (fitted off centre). This would only be for access at home to vent tank or drain if any seepage.

I definitely need at least one rear hatch. I am still pondering whether to fit two bulkheads in the rear so I can have a day hatch. This may have extra beneficial effect of giving a bit more hull stiffness although is extra work. Have read the thread re day hatches and am not 100% sure what to do yet. The boat weighs a ton already so maybe I should keep extra fittings to a minimum.

Fund are not unlimited and looking at the price of minicell foam I think it will be cheaper to make laminated bulkheads. However foam bulkheads could be easier to cut and fit.

Thanks again
Simon

Owen
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Re: DIY front hatch & bulkhead.

Post by Owen » Sat Sep 06, 2014 11:10 am

If you are thinking of fitting a front bulkhead with an ocean cockpit beware of the fumes. As for using CSM or tape, I've tried both and there isn't much difference between them, it's a fiddly job either way.

Chris Bolton
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Re: DIY front hatch & bulkhead.

Post by Chris Bolton » Sat Sep 06, 2014 12:54 pm

Jim wrote:If you don't want to use flexible adhesive (really it is better than hard laminating bulkheads in)
I don't like to contradict Jim, as he knows far more about laminating and vessel design than I do (and he's a friend), but this is not undisputed. It's one of those issues where theory and practice diverge.

It's undoubtedly better not to have hard spots in the hull, but it's also better to have bulkheads that don't leak, and I know several people who have been unhappy with flanged bulkheads. Flexible adhesive applied to clean surfaces in factory conditions is very good - but I don't think I could do a good job with it on an existing boat, that's had some use, on a bulkhead in front of the footrest. I could, however, manage to laminate tape round a flat bulkhead in that position, using a brush on a stick.

I have a boat that has rubber gaskets on flanges, and have had a leak from cockpit to day hatch, presumably due to hull flex. I've sealed over the rubber with Sikaflex, which was relatively easy as this bulkhead is easy to reach. Since there was also another leak through a deck fitting I can't say for certain that the bulkhead was leaking - the point is that I've tried flexible sealant and it's not something I'd like to try in areas I can't reach directly.

Chris

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Mikebelluk
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Re: DIY front hatch & bulkhead.

Post by Mikebelluk » Fri Sep 26, 2014 10:52 pm

Here's a link to my retro build hatches to my cedar strip boat.
http://bluggery.blogspot.co.uk/2012/02/new-hatches.html
Now I have nice big waterproof hatches I am happy, but it was a pig of a job, which would have been easier if done during the initial build.
If anyone is considering retro fitting hatches I recommend using epoxy rather than polyester resin to give you extended working time, as well as extra strength and flexibility to the work.

Additionally I have just repaired a fairly new boat where the bulkhead behind the seat had parted from the hull as a result of a roof tile landing on the outside seam. Although the bulkhead appeared to be well glassed in, it had simply separated from the hull as result of the shock, and the owner was at a loss as to why his day hatch was always wet; epoxy and a reinforcement of 2 x 2'' glass tape has cured the problem.

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Simongelder
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Re: DIY front hatch & bulkhead.

Post by Simongelder » Sat Sep 27, 2014 10:44 pm

Mikebelluk wrote:Here's a link to my retro build hatches to my cedar strip boat.
http://bluggery.blogspot.co.uk/2012/02/new-hatches.html
Now I have nice big waterproof hatches I am happy, but it was a pig of a job, which would have been easier if done during the initial build.
If anyone is considering retro fitting hatches I recommend using epoxy rather than polyester resin to give you extended working time, as well as extra strength and flexibility to the work.

Additionally I have just repaired a fairly new boat where the bulkhead behind the seat had parted from the hull as a result of a roof tile landing on the outside seam. Although the bulkhead appeared to be well glassed in, it had simply separated from the hull as result of the shock, and the owner was at a loss as to why his day hatch was always wet; epoxy and a reinforcement of 2 x 2'' glass tape has cured the problem.
That looks awesome! How many layers in total did you use in order to make it strong enough to withstand placement and removal of the hatch lids? Did you just use carbon fibre or did you mix the layer materials under the CF? This was not how I envisaged doing the recesses for my Nordkapp but it may be a game changer now I have seen your method.

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Re: DIY front hatch & bulkhead.

Post by flat earth sails » Sun Sep 28, 2014 8:02 am

I'm triying to find time to start my 1st striper, iv got the milling done, iv got the stations and strong back ready to be set up, I'm liking the b
Hatch method, I will be yousing the same on mine , I think both the carbon and the wood will look good together.

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Mikebelluk
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Re: DIY front hatch & bulkhead.

Post by Mikebelluk » Mon Oct 06, 2014 7:58 pm

@ Simon, I used 2 x layers carbon fibre and 5 x layers 200gm glass cloth with black tinted epoxy resin.
The hardest part was glassing the surrounds from the inside to the boat working blind, so I used a few cheap mirrors and lights to see what I was doing. As the hatches are the biggest ones available, I probably overdid this part, but vital to get the inside of the hull well roughed up so the resin sticks well

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Simongelder
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Re: DIY front hatch & bulkhead.

Post by Simongelder » Wed Oct 08, 2014 10:23 pm

Mikebelluk wrote:@ Simon, I used 2 x layers carbon fibre and 5 x layers 200gm glass cloth with black tinted epoxy resin.
The hardest part was glassing the surrounds from the inside to the boat working blind, so I used a few cheap mirrors and lights to see what I was doing. As the hatches are the biggest ones available, I probably overdid this part, but vital to get the inside of the hull well roughed up so the resin sticks well
Many thanks Mike. That layup certainly won't flex!

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