Sunday, 26 February 2012

Fun with a pressure washer

There are those that say you should never use a pressure washer on a boat. It can damage the paint, tear off mastic around fittings, and cause leaks. I say if the paint is so easily damaged, and the mastic not tough enough to withstand such treatment, blast it off!

The one downside of keeping my boat at Old Mill Creek is that in winter, there are about 3 months when the sun never touches the boat. To the south of the boat is a hill covered in trees. The trees form a horizon which very closely follows the path of the sun across the sky. One day, you've got the sun all day. A few days later, the sun is just below the trees, all day. Old Mill Creek enters it's shady season.

During that time, the dew often stays on the boat all day, and work outside is rarely pleasant. Painting and epoxying is hopeless. Best to forget about the outside, and watch the boat turn green.

But now, the sun is back! Hurray. I'm the owner of half an acre of plastic covered in green slime! A day with a pressure washer transforms the boat. Still not pretty, but you can see where there is work to be done.

I'd made the cockpit and the aft platform from panels of foam sandwiched in polyester and glass. The panels were laid onto beams, screwed and epoxied down, and the joins glassed over with tape and epoxy. I'd hoped to be able to paint gel coat onto the joins, and phoned the manufacturers (West) to check whether this might work. I'd found conflicting stories on Google. West advised me that the get coat would stick fine, so long as the epoxy was entirely cured, sanded, degreased and so on. I followed the advice. Here is one of the joins, after the pressure washing:

So even after the most careful attention to detail. the bond between the (textured) gel coat and the epoxy has failed.

I'll paint over such places with epoxy primer when the weather is warm enough.

I'm pleased to note that none of the mastic I used around deck fitting or the windows was damaged at all by the pressure washer.

The pressure washer doesn't send a constant stream of water out of the nozzle - it sends pulses. I noticed that the sound it made on the deck changed occasionally, and realised these were areas that had been damaged and there was some delamination. Some of these places, I could see cracks in the gel coat when I looked closely, and it seems that something hard and heavy was dropped onto the deck in these places. Before I paint the deck, I'll pressure wash it again, and note these places. There were only 3-4, and just small areas, so they won't take long to fix with a grinder and a bit of epoxy, glass and filler.

Next time I consider buying a dirty boat, I might offer to pressure wash it for the owner first. It's been quite revealing.

Thursday, 16 February 2012

Dealing with fibreglass water tanks

When I built the lockers in the cockpit that can be used for holding fish, I found there was a food grade polyester resin. It was around twice the price of normal resin, but it doesn't give off styrene when it is cured, and so wouldn't taint the fish.

 If my water tanks had been made from this resin, perhaps my water wouldn't have tasted foul, despite fitting a new carbon filter. Although since the plumbing to and from the tanks consisted of standard transparent hose, I guess the water would have been tainted anyway. A good way to pollute your drinking water is to use transparent hose, to let some light in. Algae then inevitably grows and starts a food chain allowing other little beasties to reproduce. The hose solution is obvious though - use normal household plastic plumbing pipe. It's cheap, easily available, flexible to some extent, and doesn't impart unpleasant chemicals or flavours into the water. Why anyone would use hoses and jubilee clips is a curiosity.

 I considered dumping the tanks, but I like the size of them:


They're as big as they could be fitting between a couple of bulkheads under the beds, and shaped to fit close to the hull. I measured them - 150 litres. This to me is a huge amount of water. Last summer I sailed alone from the Azores to the UK in 8 days. I had plenty of water on board, and made little effort to save water, but used just 25 litres. At that rate, with two of these tanks aboard, I could easily manage for 96 days. Perhaps if I caught rainwater from the coachroof, I could go on indefinitely. So even on an ocean crossing, I doubt I'd ever fill the tanks. It's just too much weight. But if I am going to spend a long time at anchor, or explore less habited areas, having the capacity to have so much water on board makes it no problem to do laundry and take showers.

When I bought some water tolerant epoxy to seal around the holes in my deck, I enquired whether there might be an epoxy that I could use to seal the insides of my tanks. There is, and it is called (amazingly!) AQUAPOX. Google that to find a supplier.

But how to paint the epoxy onto the inside of the tank? The stuff is quite expensive, so I wanted to do a proper job, and also, I really did want to drink water without styrene in it.

The tanks were gel coated on the inside. The gel coat would need removing first, as the epoxy couldn't stick to that very well at all. The only way to do that was to cut the tanks open. I had to do this anyway to work on them, as they are bigger than the doors.

So, I cut them in half with a grinder using a thin metal-cutting blade. I then ground off all the gel coat, and painted the insides with Aquapox. I took them back into the cabins for reassembly. I held the halves together with tape, and stuck strips of glass at various places to hold the halves in the right position. Then I took the tape off, and wrapped the joins with several layers of glass tape and epoxy (epoxy sticks better to old polyester resin than polyester resin does). With a bit of stretching and the use of a small mirror, I managed to fill some gaps in the joined are with some more Aquapox.

The Aquapox needs 8 hours at 40 degrees to cure. I managed that by inverting the tanks and covering them with a duvet, and using a hot air gun with a thermostat propped up, blowing warm air inside.

The tanks don't look pretty on the outside, but there was no point painting them, so I reinstalled them, gave them a quick rinse and started using them.

I now have water that tastes as it ought to, and no longer have to apologise to guests for the funny tasting tea.

Still, that was a lot of work which produced no visible signs of improvement! It helps to write it down!

Monday, 6 February 2012

A radical toilet

The original toilet.
The toilet that was installed when I bought the boat was awful. It was badly installed, but other than that, it was the usual bit of kit. The toilet itself was a Lavac, which uses seawater to flush, and it could be made to flush directly into the sea or into a holding tank. The holding tank could be pumped out either into the sea or out via a deck fitting to a pumpout in a marina. These pumping options were provided by one pump, 2 three-way valves and miles of piping. Have a laugh:

Sorry, it may be a little confusing. I took this photo before I had the idea of the blog. I didn't think much about photographing it through a dirty mirror. Anyway, it gives an impression of 'before'. Not quite the whole picture though. Notice the brown area I've labelled 'bulkhead'. Behind this area was the holding tank, which was kept in place by being embedded in expanding foam - the builder's variety I'd guess. A water heater that had been installed above this area had leaked around the chimney, and the water had saturated the foam. Quite a stinking mess to remove! This had penetrated the bulkhead, causing it to rot. That brown area you see is where I have replaced the lower half of the bulkhead with a piece of epoxied ply.

What's wrong with the usual system?

Through hulls. Through hulls are holes in the boat, and I prefer not to have holes in the boat wherever possible, but especially below the waterline. Through hulls need regular servicing - taking apart and greasing. Otherwise they'll become seized or just leak. I thought my through hulls were OK. When I decided to remove the original installation, I got as far as removing all the pipes and an urgent phone call took me off the job. A family crisis kept me away from the boat for a month. When I got back to it, the port hull had over a foot of water in it. One of the through hulls had had a slight leak. You never know if your through hulls will leak or not until you need them not to! Anyway, I got back to work with more certainty that removing all this stuff was the way to go.

Storage. How big does a holding tank need to be? The bigger it is, the less frequently you'll have to move to go and pump it out. On the other hand, valuable boat space is wasted, and you are storing a whole lot of unpleasantness. My holding tank had been empty for 5 years so I didn't suspect it was the source of a sulphurous smell at first. But that was where the smell was coming from, despite the tank being vented through a carbon filter, and all the pipes being in good condition and tightly attached.

Complexity of plumbing. My setup was very similar to this, but I didn't have the LectraSan electric pump. And I had one extra 3-way valve. But you get the idea.

It's complex. All those pipes, valves, tanks, and sea-cocks amount to quite a bit of expense and weight, something we're always trying to reduce with a multihull. And you don't want any of it to leak. And that deodorant is smelly in itself. Maybe a carbon filter is better, but it doesn't last that long, and doesn't retain all the smell.

Liability to blocking. Dealing with leaks is a bit unpleasant, but once you've found the leak, you might get away with fixing it just by tightening a jubilee clip if you're lucky. There's not much luck involved in dealing with blockages. I once spent a day prising apart a toilet pump in a Lavac system to undo a blockage, and then replacing the valves (which needs doing periodically because the rubber valves harden and become less efficient) only for a new guest on the boat to block it up the next day with a tampon. I hardly knew the woman - getting down and dirty with her used tampon wasn't a good start to our acquaintance.


Porta Potti.
No plumbing involved. Some unpleasant chemicals, and a requirement to empty it fairly frequently. If you go this route, you need a way to fasten the thing down in the boat. I've had the most unpleasant experience of trying to do my business at sea at the same time as trying to stop the thing I'm sitting on from sliding around on the floor. No way you can read the paper under such conditions.
Here's a model I like because of its name:

Thetford Porta Potti 165 Elegance :)

A bucket.
Again, no plumbing involved. It's easy to build into a small cabinet that supports a seat. I went for this option on my last boat, but you need to empty the bucket right away. Not good at all in harbour. Which means in port, you've really got to get over to the harbour facilities to do what you need to do.

A compost toilet.
All the rage these days. Sailing forums are full of people delighted with them, and saying they'd never go back to the old system. The catch? The price.

However, I'd been through this loop before, considering a composting toilet for a small room in my house. Commercially available compost loos are expensive. Then I came across the Humanure handbook. And once I'd read the book, I built this:

and we've been using it now for three years. No problem at all. People prefer it to the normal toilet. It doesn't smell. And produces excellent clean compost we use on the garden including the vegetable beds and even the houseplants! As it happens, I did get a degree in microbiology a long time ago, so I am aware of the possible dangers, but anyway, our composting arrangement works just fine.

But never mind the compost part. We're talking boats, and we don't want to produce compost. We just want to get rid of the waste. Cleanly.

Something that struck me when I built the toilet in the house was how amazingly efficient damp sawdust is at removing smells. Dry sawdust doesn't do it. But damp sawdust works amazingly. A thin sprinkling is all that is needed.

Still, my domestic system is basically a bucket where you sprinkle sawdust over your leavings. Everything goes in, solid and liquid, and that mixture happens to produce the right carbon/nitrogen mix that causes the stuff to really get hot (and kill the pathogens) on the compost heap. We don't want that on a boat. Really, we could do with getting rid of the liquids - they could go straight overboard (because it is basically sterile anyway). There are some compost toilets work that way, like the toilets made by Separett.

Something that surprised me was how complicated some of these toilets are. Some have screens so you can't see the contents - when you sit on the seat, the screen moves away. Some have handles that turns a mixing paddle so you can stir in your latest contribution to the old stuff. And they have extractor fans that continually draw air through the toilet and send it outside.

I'm not squeamish. I can manage without a screen. And I don't believe there's any benefit in turning the mix. People have an idea that compost needs turning (and also that lime needs adding). It doesn't. My heaps compost down to a fine black tilth without any turning or additives (the explanation is in the Humanure book). So what is this business about turning the mix inside the compost toilets all about? I think it's about nothing more than pandering to that mythical requirement, that what you need to do to compost is turn it. I think it works at a psychological level. If you mix it, it must be compost. Because you don't mix poop. And the mixer adds complexity to the whole thing - it puts you off the notion of... making your own! After all, take away the screen bit, and forget about the mixer, and what are you left with? A seat, a container and a fan.

A seat that sends liquids down one way and solids another is available on ebay. £28.89 plus postage. Quite a bit for a simple piece of moulded plastic. But it does the job, and I don't know of anything similar and didn't fancy trying to make my own. A container? A bucket, of course. And a fan? I found 4 in the attic - 12v fans ripped out of old computers. Nice and quiet. And the one I have now installed uses 0.15 amps. No problem. (Since I installed that fan, I found yet another, but this one was attached to a variable resistor - a speed control. I regret missing the option of installing that one, so that when you are using the toilet, you can turn the fan up to high speed when necessary!).

A further thought before I go on to describe my current installation. If the liquid is kept separate and the poop just sits there on a bed of sawdust with air continually drawn over it, it isn't going to compost, it's going to dry out. Poop is usually 75% water. If that is evaporated away, you don't have any issues with weight. Or smell. Ever seen those mummified dog turds in summer? They don't look nice, but they don't smell either. Most of the bacteria are killed by the drying. Most of the rest become dormant as they dry out, sometimes becoming spores. That's not entirely safe to handle, but since it is bacterial activity that produces the smell, when they become inactive, there is no smell. (Sorry, it's the microbiologist in me!)

I think those waterless compost toilets aren't compost toilets at all. They're more desiccating toilets. So I worked out a simple way to improve the dessication.

The new installation.

OK, two buckets, but still, it's not that complicated! The inner bucket has lots of small holes in the base to allow air to pass through. The outer bucket is connected to a standard 40mm waste pipe - cheap, and the bends and fittings are also cheap and easily available. The pipe leads to a small box attached to the top of a small lateral bulkhead that separates the heads from the anchor locker. A 12v computer fan is housed in there. In the anchor locker, the pipe leads down to a hole in the bottom of the anchor locker.

Before using the toilet, sprinkle a thin layer of sawdust in the bottom of the bucket, and afterwards and just enough sawdust to cover your deposit.

So how does it work in practise? Much better than anticipated! The fan continually sucks air down the inner bucket, past your deposit, through the sawdust and it is vented outside. Not only doesn't the toilet smell, but it doesn't even smell while you're using it! Currently I'm working on the boat, so I'm not there all the time, and I don't have the solar panels connected up right now. So I switched the fan off, I expected a bit of a whiff when I got back, but there was none! I realised that even without the fan running, the air passing under the bridgedeck sucks air out through the outlet anyway. You only need the fan when there is no wind at all. Any wind is enough to create suction over the outlet courtesy of Mr Bernoulli so that the smell is taken away continually. Turns out the fan is an optional extra, used only when you want to entirely eliminate smells on days when there is no wind.

Liquid goes down a tube into a 4 litre bottle, and this is easily removed to be emptied over the side, or more discretely, through the cockpit drain.

Downsides? Well, I've only tried sawdust, which I have anyway by the trailer load for my house compost toilet and my chicken house. Separette says to sprinkle soil over it. That might work. I doubt sand would be as good, as it might be too fine to allow the air to pass through easily. Seaweed might be OK. Anyway, I'll take a big bag of sawdust with me when I start out and see how we go. I have a LOT of locker space (because I kept the big fish lockers in the cockpit) and I don't mind filling them up with anything that is light weight. I don't think it'll be a problem.

When the bucket is full, it can be emptied into a bin liner and later be disposed of out at sea. At home, I'll bury it in the middle of my compost heap, where the heat will kill most of the pathogens, and the composting process will deal with the rest. It'll be ready to use on the garden in 2 years (or 3 years, just to be sure, if the heat didn't consistently build up to 60 degrees C). A bin liner, which is several buckets full is still light to carry - just as light as a bag of dry sawdust, which it mostly is.

So far, I'm very pleased with my toilet setup. It cost around £40, and will never leak. All parts are easily replaceable. And the toilet is now where the holding tank used to be (quite a bit of room under the lid for a few bags of sawdust) - which leaves even more space available for washing or taking a shower. Not a bad bathroom/toilet for a 9 metre boat!

A little more painting around the floor and a bit of titivating, and it'll be job done.

a cheap marine composting toilet


After 4 months cruising with the toilet in use all the time, I can report that finding suitable material besides sawdust is easy. Pine needles, dried sea-grass from the beach, leaf mould - anything organic that can be used to cover the solids and allows the air to pass through is fine. A bucket of such material can last a month.

But I have had problems with smell - pretty mild, but noticeable. The smell is usually under the bridge-deck, and is only noticeable when tying up the dinghy at the back. That could be acceptable,  but it's no way to greet a guest. And sometimes, fluky wind blows the smell from under the bridge deck into the front window if it is open. The answer I'm sure, is activated charcoal. The obvious place to put it is in the space between the two buckets. I haven't found any yet on my travels, but the problem isn't urgent.

Other than the occasional smell, the toilet is working out better than anticipated.

Even later:

I have found some activated charcoal at last (pet shops, used as a filter medium in fish tank filters). It was too expensive and the packet too small for me to put it in the space between the bottoms od the buckets. So I put some into a thin sock, and dropped it down the air pipe. Now, there is no smell at all! The air flow through the system is less than it was, but still sufficient. The charcoal I have used this last month is still in place, and completely effective - so my little packet could last for years.

Dealing with holes through a foam sandwich deck

I'd noticed one or two small leaks where deck fittings came through the coachroof. And I saw that there were patches of mould growing in odd parts of the inside of the coachroof, usually beneath a deck fitting. This suggested dampness in the foam. I took a screw out of a foam sandwich bulkhead and was surprised that a little stream of water flowed out. I drilled a hole through the first layer of glass lower down on the bulkhead, and another little stream came out. I drilled a series of holes, one below the other, each draining a little water out, until I drilled one, and found the foam behind it dry. No more water.

You hear horror stories of foam sandwich boats where the foam is saturated with water, and it loses strength as it is stressed when the hull is driving through waves, leaving you at some point with two thin layers of fibreglass no longer connected to each other, only a little stiffer than wet toilet paper.

When I was thinking of buying the boat, I'd heard of a survey having been undertaken for a prospective purchaser, and I bought a copy of that for £300. It seemed a bargain. The survey was rubbish. There was no mention of several problems that were evident to me after a quick inspection. Potential problems were merely hinted at rather than investigated. Vaguely, it said the design was good, most of the boat was good, but parts were shoddily built and needed attention. Rather than kick up a fuss at the waste of money, I thought perhaps I'd leave things as they were, and if I bought the boat and it fell apart, perhaps I could claim against this lazy surveyor. Maybe that was just me being lazy, ducking out of making a fuss.

I decided I'd have to rely on my own experience. It was after all my 6th boat. And nearby, I had a friend who was actually born on a boat, lived most of his life on boats, and had built a few himself. I persuaded him to spend an afternoon with me tapping everywhere, listening for a dull thud, looking for signs of delamination. We found no signs of that, and no further problems that I wasn't capable of fixing myself. On the basis that the boat was structurally sound, and that there were no problems that I wasn't capable of dealing with myself, I bought it.

With water in the foam in some places, but not others, I wasn't sure what to think. How could water get into a bulkhead at all? Certainly not through the deck. Why was there water in an upper section, but none below. And did water in the structure not mean delamination was likely? What does a dull thud sound like anyway? If I'd heard one with all our tapping around, I'd know I'd found a problem. But what if I had failed to recognise the difference in sound when you tap a solid laminate from one that was delaminating. And even if there was no delamination - how could I go about fixing these leaks, how to get the water out of the foam. Was it perhaps, time to panic?

I did. I decided to call a proper multihull surveyor. Someone with a bit of form. Someone the experts called on. Someone I probably couldn't afford, but who I also couldn't afford not to call in. I called Rob Feloy, who conveniently lives just up the road. I told him I didn't want a full survey. In fact I didn't need him to give me anything in writing, as the advice I wanted wasn't for insurance purposes nor in any way legally binding. I just wanted him to come and look at what I'd found and advise me on the way ahead. No holds barred. If I was wasting my time, he wasn't to say nice things about my boat in order to not hurt my feelings! He understood, and showed up at Old Mill Creek at the appointed time with his magic moisture meter.

First, the mystery of the bulkhead with water in the top half, and none below. Rob explained that the bulkhead was made of contour foam - that is, foam with cuts in it that can be bent to make curves in all directions. Not what you'd choose to make a flat bulkhead, but if there was some contour foam left over from building the hulls, no harm in using it.

contour foam

If the cuts aren't filled entirely, which is often the case, any water that gets through to the foam fills the voids left by these cuts. My bulkhead had a few unsealed screws through it (to hold a piece of timber in place on the other side), and leaks in my hatch guttering allowed water to drip past these screws, eventually finding its way into the voids in the foam. The reason the bulkhead was dry below a certain level was that often big panels of foam sandwich are made from several pieces of foam, which are glued together before lamination. The line of glue between the pieces of foam acts as a barrier, preventing water that has penetrated part of the foam to enter the whole of the laminate. Using his moisture meter, Rob was able to easily distinguish that part of the bulkhead that had become wet. That was neat. He tapped around just as I had, and heard no unpleasantly dull thuds. This was much more reassuring - a report of no dull thuds from a man who'd heard many a dull thud before, and knew exactly what one sounded like.

Later, I drilled a plug out of the bulkhead, and I was fully persuaded that the glass had remained firmly attached to the foam on both sides.

Rob's magic moisture meter revealed moisture in the foam in the coachroof, downhill from several deck fittings. My heart was preparing to sink, but Rob didn't seem to regard this matter as serious. Again, it would be water in the voids of the contour foam. And there were no signs of delamination. Clearly, the water would have to come out - but that's easy, with a small hole drilled through the inner layer of glass at the bottom of an area that the meter designated as damp. Rob didn't think the residual moisture was significant. If the drain hole was left open, and the source of the leak stopped up, it may eventually dry out, but either way, not too important.

I knew how a hole for a bolt through foam sandwich should be created, and it became clear that none of the holes in either the coachroof or the deck had been made correctly. Here's the right way, a way that seals the two layers of fibreglass around a hole, and provides a robust collar that will absorb some of the strain imposed by the compression applied by the tightened nut and bolt:

A hole through glass/foam/glass sandwich

Use an Allen key attached to a drill to remove a few mm of foam

Close the bottom of the hole with tape, and fill with epoxy.

When cured, drill a bolt-sized hole through the epoxy

But how could I seal a hole this way when the foam and glass is already wet? Rob recommended I contact the Matrix Composite Materials Company who could supply me with some epoxy that sticks to wet stuff! Epoxy that sticks to wet stuff! Of course! I got some, and it did! I tested a bit on a piece of wet firbreglass, and it stuck. Magic! (Matrix has many specialist epoxies - and I found good use for one of these with another job, to be described in a future posting).

A detail - when sticking tape over the bottom of the hole before filling with epoxy - sometimes it leaks. The solution is to put a small circle of mastic around the holes first, and press the tape over that. Also, add a little filler to the epoxy to increase its strength, but not too much. It needs to fill all the voids. Aim for runny honey viscosity!

A tip - if you drill through the epoxy, but don't have time to refit the deck fitting, you can fill the hole temporarily with expanding polyurethane wood glue. This also sticks to wet stuff. It expands to fill a hole, and being foam, is easily drilled out when you want to refit the deck fitting.

Another tip - apply mastic only to the deck fitting - not to the backing plate under the deck. That way, if the mastic on top leaks, you'll know about and and can redo the job. Applying mastic to the backing plate might hide the fact that the deck fitting is actually leaking, and who knows where the water might seep to?

Clearly, fixing all these holes would be a long job. Would I need to call on Rob again to check that all the holes I fixed had solved the problems? I decided I'd better have one of those magic moisture meters so that I can verify for myself that my work to remove moisture and seal up holes really was working. It was expensive, but I think it might be a worthwhile investment for anyone with a foam sandwich boat.

Thursday, 2 February 2012

The intention

My boat was in poor condition when I bought it, having sat in a boatyard for 5 years with quite a bit of rainwater inside. Some parts of it were badly built too, and some aspects of the boat (though not the design) I considered poorly thought out. I'd done the minimum amount of work to get the boat sailing and have a shot at the commercial fishing idea. I've tried the fishing. As an experiment, it demonstrated a lot, and I guess in that sense it was successful. Unfortunately, it demonstrated that commercial fishing from a sail boat in the English Channel would never be anything but a hobby. However, part of the reasoning behind the fishing business was that if it failed, at least I'd end up with a boat! Which is more than I have been left with after some previous enterprises.

So, time to go cruising again. South. Somewhere warm and sunny.

This is my first catamaran, but my 5th or 6th(?) cruising boat, so I know what I want in a boat fitted out for cruising. The first part of this journey will be repairing and adapting the boat in preparation for blue water sailing. It may be of interest to others preparing a boat for an adventure, or contemplating a similar enterprise. I think it might help me too - I have already done much of the work that was needed yet the boat still looks like an abandoned wreck! It'll be helpful to document the improvements, because so many of them are invisible and easily forgotten, and so when I ask where did the time go, I can look back and see what has been done.

Here's the boat in Google maps street view. One of the improvements I made previously has paid off. I fitted some oak/epoxy/glass shoes to the hulls so that it could take the ground without damage (more on this in another posting). Instead of paying a fortune to keep the boat in a yard, I can put it on this river beach. The boat floats only on spring tides. Usually I can back my car right up to the boat, making it easy to transfer tools and materials. Excellent place to work. Nice and quiet, with kingfishers and buzzards and other birds of prey a common sight. But in December and January, the sun never hits the boat, and it is always cold and damp. Nicer then to try to find something interesting to do indoors, nice and warm! A blog, maybe...