2006 building logs

June 2006 Turning the Port Hull this month?

I have titled the month "turning the hull" for the last 3 months, maybe this month is the one!!

It would be fair to say that we haven't got much done in the last couple of months and that we should have been reporting, some time in May on the turning of the first hull, maybe even April if we hadn't made the silly bog mistake. I am not too concerned about it and I guess in the end (and looking back on this period of the build in a year or two or even after the launch) it will seem insignificant or as just a part of the process. I include reports of these low spots or nothing periods because they are relevant to new readers interested in all that comes with building including mistakes or periods of inaction because they can happen. Rarely in any pursuit are there no ups and downs or periods of inertia and these are just the episodes of the build, good or bad, interesting or dull, positive or negative. I have promised (to myself) to record it all. So I apologize to the readers only interested in reading the technical stuff, of which there has been little lately. I am working on learning how to link from an index to parts of a page, so you can skip all the rest of the stuff and go only to the parts of more interest. More on that when I learn how to do it. And hopefully there will also be more rapid progress in future.

3 June 2006 Not as thick as some

After my posts about my coving not being as neat as I would like and some of my coves running I had an email from Randal (Wilderness 1100) suggesting my mix is not thick enough, which reminded me of a post on this site warning that the material seems a lot thicker in the pot than it is when applied. He also mentioned that he got his coves just fine and didn't use chopped strand either and that I just needed to thicken the mix..

So today I taped the back of bulkhead 1, both sides of Bulkheads 2 and the front of bulkhead 3. None of these will be visible (buoyancy chambers) so it was a good area to experiment on. I made the filler progressively thicker until I was satisfied that it would not run, and I also decided that perhaps part of the problem was also because I was making the cove to big. I had a radius about the size of a coke can on one end of the spatula that I had been using and these coves are the ones I found would sag. The other end of the spatula is the radius of a 20c piece so I decided to use that end on these coves. I figured that the less material in the cove the less likelihood of its weight causing it to sag.

Randal also suggested that I wait a while before applying the tape to give the cove filler a chance to harden a little to retain its shape when the tape is wet on. I coved all 4 bulkhead joins and then applied the tape to the first cove, then second etc. The cove had almost set but I perhaps could wait a little longer still as it was still a little soft under the tape, but it did retain its shape a lot better. I also used a special tool designed specifically for pressing the glass into the correct positions to make sure there is good contact all over and no air bubbles. Tomorrow I will start a little earlier (I started at 12 today) in order to get a lot more done but also to allow more time for the cove filler to set harder.

4 June 2006 By George I think he's got it

The plan was to start earlier today but sleeping in got the better of me again. The first thing I did today was to check to see if the results of yesterdays work was as good as the cove I did where I sanded it smooth before applying tape. This is the benchmark cove. If I cant get my coves to look as good as that when applying the cove wet on green then I will revert to sanding them first. More work but I want a boat that looks as good as it can be.

Well these coves looked fine. Still a little bump here and there but with more practice I am sure they will look even better. And I also think more time for the cove to harden will also result in a much smoother finish.

More importantly I guess from a structural point of view (which is the most important) is that the glass is correctly bedded to the cove and uniform and smooth which will result in the best load spreading characteristic.

So I managed to tape the back of bulkhead 3 and the front of bulkhead 4. The rest of the coving will require the removal of the temp bulkheads so that I can have a continuous cove along the panel joins. I like to cove these before I cove the bulkheads so that the bulkhead coves are over the top. I find this neater. So I only have the 3 sections between bulkheads 4 and 5, 5 and 6, 6 and 7 to go.

I also finally got the wall mounted West pump working properly today and it is much easier to use than the plastic pumps on the drums. One pump up of the handle and you get the correct 5:1 mix into your mixing container. You don't have to remember how many pumps you have done (if you are making a reasonable amount of resin using the drums you might pump say 5 of each or 10 of each but you would pump 10 from one drum then 10 from the other but must keep accurate count). With the wall pump you can make as many pumps as you need and stop anytime and you already have the correct mix.

The problems I had getting it working was that I used a hose into the 200 litre drum of resin that was too weak and it would suck in on itself when I pumped, closing off the flow. I bought some heavy duty hose (washing machine hose actually) and that solved the problem. The other problem was that the hardener pump didn't seem to be sucking. In fact it doesn't suck. It relies on gravity to feed the reservoir and the pump action then pushes the hardener out of the outlet (the resin hose does suck but it has to lift resin from the bottom of a 200lt drum). I mounted the hardener drum (its only 20 litres) over the pump and that solved the problem. The only thing I have to do now is to mount the pump in a more solid and convenient place (it is currently screwed to a heavy piece of timber but the timber is not attached to anything) but because the resin drums are full I cant move them yet (they are on a pallet) so until I make the second hull and use up all of the panels along the wall that are in the way I will persevere with the pump where it is.

So all in all a good weekends work. Nice to get something done. It has been a while. I am almost ready (mentally) to finish sanding the bog (I am about 1/4 done). Once I have finished the coving and there is nothing more to be done to the hull except fair it, I will have no choice but to do it. And then once it is done and the hull is turned, I do it all again.

9 June 2006 Coving is improving

I have coved the panel joins between bulkheads 4 and 5 and the back of bulkhead 4 this afternoon. The panels were already coved and I had sanded them yesterday. I also removed the temporary bulkhead between bulkhead 4 and 5 (TBH1) and coved these last gaps where the temp had been but taped over these wet on wet. Removing the temp was of course necessary so I could tape in single lengths between the 2 bulkheads. And I like to have the panels taped first then the bulkhead coved and taped over the top. As I have said, this is a much neater finish.

The cove on the back of bulkhead 4 (port hull bedroom, the one with the door to the walk in robe) looked quite good so I am now happy with the finish of these wet taped coves. I had a little filler left when finished so rather than throw it way I used it to cove the outboard bottom (which is actually the top with the hull upside down) which will be the most visible section of coving. I will have to sand it because I didn't glass it, but I don't mind, it is a small easily accessible section, but I only did so because I didn't want to waste the filler.

I actually scared myself as I attempted to remove the first temp bulkhead, and this should serve as a caution. The coving I had already done was tight up against the temp bulkhead so it could only move down. I had attempted to lean it over rather than try to drop it down on my own but it wouldn't move either forward or back because of the filler up against the mdf. It was then that I had a scare run through me. What if I hadn't removed all of the screws before I glassed the hull. What a job it would be to remove the temp without doing some damage to either the hull or the temp bulkhead (which I need to use again on the other hull) if there was still a screw holding the temp in place. So the lessen is make sure you remove all the screws before glassing.

In the end the temp just dropped out so there were no screws. A relief. I still have 4 more temp bulkheads to remove and I am pretty sure I removed all the screws from under the glassed areas and now there are only 2 screws still in place at the edges so not under the glass but I will breath a little easier when I have removed all the temps.

I also had a little mental dilemma about removing the temp bulkheads before I have faired the hull. The temps also have legs on that help spread the load (of the weight of the hull) onto the strongback that once removed will reduce the number of legs by nearly half and I will also have my weight on the hull and into the reduced legs when I am fairing, especially as I fair the under bridgedeck side as I use the bridgedeck returns as a platform for my walking boards. So I thought to myself, damn I am going to have to sand sooner than I think. Until it occurred to me that if the temp bulkheads are pushing the hull panels out in any places that might spring back in after the temps are removed, it would be best that they are removed before I fair it, because believe me nothing would make me crankier than having to re fair the hull (having expelled so much energy avoiding doing it in the first place!) if the shape was to change after I have sanded it fair. So if there is any movement it will now occur before fairing, not after.

So having decided that little dilemma I proceeded to remove the temp bulkhead. After all, the hull would only weigh around 300kgs and there will still be 8 sets of legs holding it up while I sand it (eventually!)

11 June 2006 Coving almost finished

Yesterday and today (6 hrs each day) I have finished coving the sections between BH3 and BH4 (the port bedroom) and BH5 and BH6 (the main bathroom) leaving only the section between BH4 and BH5 (the saloon or more appropriately the halls at the bottom of the stairs from the saloon). Then once that is done tomorrow, I will have completed all of the work on the inside of the hull at this stage leaving only the sanding on the outside to go before turning and starting on the second hull. Perhaps the only other thing might be to do a quick grind off (using a sander) of the sharp points at the edges of the tapes as they can be sharp. I will also run the router along all the edges to remove the tape overhangs.

I have removed all of the temp bulkheads. There were no screws still in place and they all dropped out easily thanks to the sticky tape on their edges to prevent any glue from sticking to them. I was reminded how heavy the mdf temps are. I would guess that the temps weigh more than the hull does.

Finally you can see down the hull through the doorways and see the entire length of the habitable area inside of the boat.

A tip on applying the tapes to the bulkhead joins. Make sure you apply it with slack to the outside of a turn (against the hull panels). It will leave you with excess slackness on the inside of the turn (on the bulkhead) but this smoothes out with your fingers. If you are too tight on the outside of the turn the glass will not stretch, it will lift off the bulkhead and you will have a lot of trouble getting it to stay attached to the bulkhead. Another tip (that Randall gave me) is to brush on some resin an hour or so before you want to apply the tape and it will be tacky and help to get the tape to stick to the panels easily.

 

Once the inside is done tomorrow I will have no more excuses, I will have to start sanding the outside of the hull then apply the numerous layers of high build and sand them off again. I actually have been sanding here and there and have about a third of it done. I need to apply a little more bog and then sand those sections again. I have been exaggerating my avoidance of the sanding, but it is a bugger of a job and I wouldn't wish it on anyone. I reckon it is the sanding that weeds out the gunna's from the doers. (For those not familiar with Aussie slang, a gunna is someone that is going to do something one day but never gets around to it, as in "I am gunna do that one day").

I noticed I passed 400 man hours today. The estimate for the build is 4000 hours so I am just on 10% done. And I think I will finish the first hull this month which is about 10 months, but I think I can finish the second in 6, because I spent the first month gluing all of the panels (for both hulls) which I don't have to do again, also I have a bit more of an idea what I have to do (and what I don't have to do) which will save a lot of time and finally I lost almost a month in Feb whilst overseas and a month due to the bog mistake so that's at least 3 months less. So hopefully in January I will be ready to join the hulls.

12 June 2006 Coving all finished

Queens Birthday long weekend was a productive one. I have finished all of the coving and glassing of the hull panels and bulkheads and the temporary bulkheads have been removed. Today I managed to glass the last section, the middle section between BH4 and BH5 the main living area, known as the saloon. It is also the widest section. As it was the last bulkhead taping, I wanted to take photos to illustrate leaving slack on the outside of the turn to be sure it adheres to the panel without lifting but unfortunately I had a problem with the camera and no time (with wet tapes to finish and resin on my gloves) to fix it, so it will have to wait until the second (starboard) hull.

I now have to (probably tomorrow) trim the overhanging glass as it is sharp and must be trimmed ready to turn the hull, but before that, as readers will no doubt know by now, I have to sand the rest of the bog fair, then high build (thick sand-able paint) a few times sanding progressively finer until I am satisfied that the boat is fair to the middle of the main hull panels. No more excuses, so as soon as I get back from Melbourne (yes I am going again tomorrow night for the rest of the week) next weekend I will be onto it. So tomorrow I will trim the glass overhang with a router and generally clean up ready for the sanding.

A couple of tips I have picked up whilst doing the taping, are if you have any loose strands of glass at the edges (and you will get lots of them) resist the temptation to pull at them, they run the whole length of the tape and cause more mess trying to remove them than just letting them be, and it will also pull the wet glass away from the panel so you will need to re apply it. You can easily snap them off when the resin is set although you may get them caught in the glass roller so then you may have to cut them, but use scissors rather than pull them.

The other tip is that you have a lot more time to work with resin and filler in winter than you do in summer. You are lucky to get 20 minutes in summer when the temperature is over 25 degree (and usually closer to 30+) but in winter when it is around mid teens you have nearer to an hour before resin will be unworkable and the coving filler is even longer. Today I used some left over filler that I had mixed more than 2 hours earlier. This means you can safely mix larger batches of resin or filler and be sure to be able to use it all before it sets or goes off. A few times in summer we had much smaller batches go exothermic on us and almost spontaneously combust, but there was never a hint of that over the past couple of months.

I have been trying to get a 1 meter 3M sanding board but they are hard to find and they are super expensive (no one stocks them anymore and the price has recently gone up). They are made of a lightweight composite material and have hookit on the sanding face for attaching the sand paper. They are made in either flexible or rigid. I have decided that for now, I cant justify $160 on a sanding board so I am going to attempt to make one. I am going to use an offcut of Duflex as it is also lightweight and over 1 meter should not be too flexible but may have just a little give in it which may not be a bad thing. I will contact or resin some hookit to one face and attach handles to the other and see how it works. It is really important that it is as light as it can be as it is hard enough work without having to use a heavy board all day. I have bought 2 $6 trowels for handles and will resin and glass them onto the Duflex. On the other side (the sanding side) I will first glue down a layer of dense foam padding which I hope to get from Clark rubber. Then onto that I will glue the hookit and I should have a working torture board. More on this when I finish it and test it.

One final thought. I have spoken to some builders that weigh their glass and their resin to ensure the correct ratio of resin to glass (I think it is 50:50). I don't bother to do this for 3 reasons and 1 of them is laziness. The other 2 are good reasons I think. Firstly I have been shown (by Brett Schionning) how to apply the correct amount of resin to correctly wet out glass (and if I use the wombat, it does that for me) and I also believe that us amateurs seem to err on the side of using too much resin if anything. We are taught to constantly be vigilant to watch the weight of the boat, in other words don't use too much resin, bog, etc (too much resin does not make the boat stronger, just heavier, so long as you have not used to little). The other reason which I feel is far more compelling is, say I have weighed the correct amount of resin for the cloth I need for the job and I get to near the end of the wet out and I run out of resin (meaning I have put too much resin onto the glass already wet), what are my options? To not wet out the rest of the glass so that I don't go over my allowed resin content? I have already done that on the rest of the job anyway and I can't leave glass un-resined. So there is really no point to me in weighing the resin and the glass so long as I am sure that the glass is getting enough resin and that all the glass is wet. I am fairly confident I am getting this right.

All in all I have really enjoyed the weekend. It was great to be working solidly on the boat and to feel like I was getting something done for a change.

14 June 2006 More thoughts

I am in Melbourne for a few days and a few more thoughts that I want to report on have come to mind. Just on the coving and taping, like most things in life, I got better and faster as I progressed and you can see that progression in the tapes and probably be able to pick the order that they were done just by looking at them. Except for the very last one. It gets dark around 5pm now and I usually start around 11 and work through till around 6pm. We have fairly good lighting in our warehouse but in under the hull I need a light and have been using one of the cheap halogen spotlights. They are great, except the bulbs are super fragile and even the slightest movement when they are hot and the globe goes. The lights cost $7 with 2 globes but I have gone through 4 globes in 2 weeks, at $3 each!! Now that's not a lot of money but when you consider the small price of the light (including a spare globe) it is almost cheaper to go buy another light! But more costly than the globes is the inconvenience of blowing a globe half way through a tape wet out. The lamps run so hot, it takes half an hour until it cools enough to change the globe (and luckily I have spares!). I didn't have time to wait for the lamp to cool so I pressed on with the very last tape in near darkness with just a very weak flashlight every minute or so (I had to keep putting it down as I need both hands to apply the tape). The end result was not a terrible job but not my best work. The second last tape was the best and so on back. The moral of this story is that I am going to try other lighting methods as the halogens are not reliable enough. More reports on this as I come up with the best option.

I also want to take this opportunity to make 2 comments on emails. Over the last few days I have received a lot of really lovely emails from readers and I want to thank you all for them. They are a great part of writing this site and I love to hear from you. Please feel free to email at anytime, I always find time to answer them. Some of the emails are from fellow builders with advice and encouragement. Thank you all I very much appreciate it. It is very helpful and motivating. And some emails are from possible future builders (this also came up on the Schionning Forum) and to you all I say go for it, you wont regret it. The sooner you start the sooner you will finish.

Finally, yesterday before we left, I got a chance to start a test on a product that may be of interest (well the result wont be in for some time) to other builders. I am planning on a very lazy retirement on board our boat, so everything I can do to minimize necessary maintenance now I am going to do if it is cost effective. That is one (not the most important but important nonetheless) reason we went for the bi-rig, unstayed masts means less maintenance of rigging. To this hassle free end, we are investigating a new anti foul method called Pure Seal. It is a rubber like coating, that goes on as a paint and will adhere to any substance and nothing will adhere to it once it is cured, so the theory goes. McIntyre Marine handles the product in Australia and Schionning are an agent of McIntyre. Sam at Schionning has sent me a piece of checker plate coated in the stuff. I have hung it off our pier and will report every 6 months or so on how it is going. If the blurb is true, a simple walk along the pier dragging the piece of plate through the water should result in anything (and they claim it is almost impossible) that has managed to get a grip to fall off just by the water moving past. A yacht in normal motion would do this. So that means never having to scrub the bottom and antifoul for years at a time (they claim 10!). Assuming the stuff works, my only other concern is that the stuff seems to scrape off very easily. I scratched the stuff off the high points of the checker plate with just my finger nail so imaging what a grounding along a sandy bottom might do! I will have to investigate that a little more. Anyway stay tuned.

* I have added a picture to illustrate my point on corner coving above.

I should be back to work on the boat on the weekend.

17 June 2006 Let the sanding begin

Well today I had no choice. I started sanding the hull. Well started isn't exactly accurate. I have done some sanding. But today I started the last stage of the port hull. Once it is sanded, faired and sealed, it is time to turn it.

After chatting with another builder (Alan building an Oram 44) and because he has used and recommended a Bohler sander, I have decided to give this new electric sander a try. I noticed it a few months back and wondered if it would be an effective sander for the boat. Using an orbital sander to remove the bulk of the bog is ok but is fraught with danger because an ordinary orbital has such a small footprint that it is very difficult to sand a large flat section without undulations. So the larger the footprint the safer or more likely you are to maintain a consistently flat surface. Furthermore, any sander that rotates has a sharp cutting edge that contributes to the risk of undulating rather than flat sanding.

The difference with the Bohler sander is that it is made up of 3 rotating discs the size of 1 normal orbital disc which in turn also rotate as 1 making the sand area around 300mm instead of the usual 120mm. Because all 3 rotating discs rotate the cutting edges are constantly in motion and this minimizes the chance of the cutting edge damaging the smooth flat surface you are trying to achieve. Finally, (and I didn't know this until today) the Bohler operates at very low speeds, with each disc as well as all 3 rotating very slowly (only 100rpm). The Bohler sander is only available from Super Cheap Autos, which is not renowned for quality brand name products and as I had already killed a Ryobi sander I had my doubts as to whether the Bohler could stand up to the work rate needed to finish the hull. But to my surprise the sander works very well and seems to be able to stand up to the workload. The disc pads are a bit fragile (they sell spares) but other than that it works so far. The down side is it is slow and heavy.

I used the Bohler to flatten out the highs and lows of the bog and on the particularly high (thick) sections I reverted to the orbital, because it has a faster rotation speed it has a faster cutting action with the same grit paper. (I am using the coarsest paper I can get to start with W40). I managed to sand about half the outboard side of the hull today. So at this rate it will take me around 3 more days to finish the hull to the first stage of fairing.

The next stage is to fill the low areas (where the sander barely touches) with another thin layer of bog. Then I have to use the torture board to get a totally flat surface by sanding down the hull again but hopefully the bulk of the work will have been done by the electric sanders.

As you may know, I am making my own torture boards because the 3M ones are so expensive. I bought 2 cheap trowels because this was the easiest way I could think of to get the type of handles I wanted. In fact I searched Bunning's and couldn't find handles. I glassed them onto a 1.2 meter piece of Duflex the width of the sandpaper. I also got some dense foam from Clark Rubber to go between the sandpaper and the Duflex. I was planning to apply Hookit to the foam in order to attach the sandpaper. So far the trowels and the foam have only cost me $20 and 4 meters of Hookit (it doesn't come in shorter lengths) is $30. I may skip the hookit and attach the sandpaper with blocks screwed to each end. Either way it is still way cheaper than a 3M board.

I have marked the waterline and the line at the chine above the waterline on the outboard side of the hull. This chine is the only really important one. The rest are below the waterline and whilst I want to do a fairly good job, they are not visible (and painted over with antifoul paint) so I can afford to be less fussy. The plan is to sand to the line (on the above waterline chine) from above and below but leaving the line in place. This way I will have the line as a guide as it is very important for this line to be straight and level with the waterline. This line will be visible at around 500mm above the waterline when afloat so if it is not parallel to and straight in relation to the waterline it will show. In fact the antifoul line will be painted about 200mm above the waterline making the chine around 300mm above that.

Tomorrow I will finish attaching the foam (using resin) to the base of my board. I have done a small section to see if resin is effective with the foam. If not I will switch to contact. After that I will continue with the sanding using the electric sanders.

18 June 2006 Half Fair?

Another 6 hours of sanding today and I have now faired half the hull, the outboard side. Well almost. I still have some low spots to fill in and re sand but overall I think the bulk of the work on the outboard (and most visible) side of the hull is done. I will also build the chine in the middle of the hull above the waterline a little further so that I can fair this line properly. I have not yet hit the hull with the long fairing boards. I will do this after I have filled the low spots and built up the chine. I don't think there is much to do, it looks and feels quite fair.

A further note on the Bohler, because of its super slow rotation speed it seems to create far less dust in the air than a regular orbital, and the bulk of it goes into the dust extractor or falls to the ground. With a regular orbital, the disc is rotating so fast that it propels dust off into the air at a higher velocity than the suction of the dust extractor. Dust in the air means dust on everything because it eventually falls and settles on everything.

As I did yesterday, I took the thick high spots down with a regular orbital, then used the Bohler to obtain a flatter surface, almost fair. Here and there I have some low spots and after cleaning off the hull (with water) to see and feel the hull without the dust I noticed I still have a few higher spots too, that could do with a touch more sanding, but I will do this with the torture board.

It sometimes appears from the size of the lip caused by the tapes under the bog, that I would need extra filler but because the bog flows over the tape and basically is the same thickness all over and when the thickness over the tape is removed the hull is getting close to fair. I have taken about a millimetre off the tape but only a tenth of a millimetre from the valley leading up to it which results in a smooth transition.

There are 2 ways of achieving a fair hull. One way is to fill the void between the tapes so as to end up with a completely flat surface from tape to tape (high to high). This would be the most accurate or aesthetically correct way to fair. The other method, (the one I prefer) is to fill for about 250mm from a tape edge and feather the bog out to remove the lips. This creates in theory a slightly concave panel between the tapes. However there is only one tape that is visible above the waterline on the outboard side of the hull (the bottom tape on the upturned hull which will end up about 300mm above the waterline) and the rest are below the waterline, and the inboard side of the hull is underneath the bridgedeck and also hardly visible (except at the bow and stern). The size of the gap between the visible tape and the next tape that ends up under the waterline is about 600mm at the centre of the hull, tapering to about 150mm at the bow and about 300mm at the stern. If you fill this area so as to be level tape to tape you add a lot of bog. But the gap is so large that it is impossible to see that there is a slight concave surface and as I said the bottom of the concave panel is below the waterline. One final note is that the gap between the tapes on the middle picture above will eventually be covered with antifoul paint, which is a thick uneven paint anyway. So there is much less need to be super fussy on these sections of the hull.

The different colours in the pictures above is because some were taken after dark under the lighting in the warehouse which effects the color balance. After I had finished sanding for the day I decided to wash the hull down so that I can get a better idea of how smooth the hull is without dust all over that gives the impression of smoothness. I can also see the highs and lows that need more sanding or filling (then more sanding!).

By 5.00 I was finished sanding for the day so I used the spare time to vacuum and generally clean up. The dust is not Jo's favourite part of the job (in fact she hates it) so the less dust around the happier she will be tomorrow when she has to work in the warehouse. If you cannot stand dust or at least tolerate it for a while then you are going to find building a boat difficult.

Well it feels like I am about half way and I get to rest for a week (work feels like rest by comparison) and I should be able to get the other side of the hull done next weekend. At this point the sanding is as bad as I thought it would be. I don't like it at all. It is harder work than I would like to be doing on a regular basis (or even every now and then!), luckily you only have to do sanding for about 5% of the time (my guess) on the whole build or about 200 hours including the interior. I wonder how I will feel once I have finished the hull, maybe I will think it wasn't that bad after all, who knows? Having said that, it is very satisfying to have a smooth hull.

19 June 2006 Just a little more

I managed about an hour of work on the boat today. I started sanding at the bow of the inboard side of the hull. The inboard side has a much different shape to the outboard side, and unlike the outboard side there is more of a curve to the hull both top to bottom and from bow back as the hull flares wider. This presents both problems and advantages for fairing. The advantage is that irregularities on a curve are harder to see than on a panel that should be flat but isn't, and difficulties in that a curve is harder to fair than a flat section. This is where the Bohler is quite handy. The 3 sanding heads are on pivots and can sand curved sections (both convex and concave). I sanded the first 2 meters of the bow today and whilst there is still a bit of work, I only worked for an hour and got it fairly smooth. I still have some filling to do on sections but overall it looks ok. I may also use high build to fill as the gaps are less than a millimetre. I am not sure as to how much I can depend on highbuild to fill yet.

I have also finished the sanding board, except for adding the hookit (which is optional, as I could attach paper by using blocks screwed to the top if I wanted). I figure hookit will keep the sandpaper more taught against the board and also allows for easy changing of paper, both when worn or when changing to a different grade. At around $30 on material (including $11 for handles = 2 x trowels, $10 for a sheet of foam of which I used a 1/4, and $24 for 4 meters of hookit again using a 1/4 of it, and 500mm of glass and resin) this is a bargain when compared to what 3M are asking for a 1 meter composite sanding board at $160. The weight is around the same and I figure the use is about the same. If it works well I am thinking of making more of them in varying lengths, maybe a short one at say 40cm and a really long one at 2 meters.

I will try to get another hour in tomorrow. Maybe sneaking up on it is not such a bad idea.

25 June 2006 Full Fair?

Another weekend of solid work on the boat. Well 2 six hour days. To me unless there is a task such as glassing that must be finished in one session so therefore the session lasts as long as it takes to finish, 6 hours is about the limit. I start around noon and finish at 6pm. I know I could get more done if I worked longer hours but it is a hobby not an obsession. Besides, sanding is hard work. I also managed 6 hours during the week.

So I have now sanded the whole boat. I then filled in low spots and tape edges with more bog and used the trowel edge to scrape the bulk of the bog off so there will not be too much more sanding to do. I have also built up the edge on the main chine (the only one visible above the waterline) so that I can be sure to have a straight chine turn. 

From now on all of the sanding is with the sanding board I made. I have attached the hookit and attached the paper and the board works great. I will sand up to and down to the main chine before rounding the chine off once I am satisfied that it is straight and fair. I will also sand along each panel with the long board to be sure it is completely flat and smooth. I am hoping that the Bohler has done the bulk of the work and that there wont be much hand sanding.

I have marked a line about 250mm below the main chine. The main purpose of the line is to mark another line along the chine so as to be sure the chine is exactly straight. The method is to mark a centre line along the chine then another line 10mm above and below. You then sand to these lines, then sand the chine flat from the centre to the 2 lines then round off the 2 new chine edges. As the chine lines are sanded off I will still have this lower line to sight (and or measure) against. It is also the lowest point to which I wanted to fill so I also had a straight line where the surface rises to the high point over the tapes. I also plan to mask the hull at progressively lower points with each coat of highbuild so that the coats also feather out.

I hope to have all of the rest of the sanding completed next Saturday. Unfortunately I wont get to do any work during the week as I am off to Melbourne again on Tuesday for the rest of the week. I am fairly certain the hull is already quite fair. I tried turning the lights off and shining a torch along the hull looking for dark spots caused by high spots casting a shadow but didn't seen any. I may have some low spots. I am told that the moment the white high build goes on, any imperfection will become instantly visible. It is possible to fill again on top of the high build but the idea is to minimize this.

Another trick I have been told is to spray a fine mist of dark spray paint onto the hull and sand it off again, which will highlight the highs and lows, as the highs will sand the paint off first, but this is a last resort if I cant get the surface looking fair without it. I also haven't sanded the chamfer chine turn. This turn is concave so I need a rounded sanding block, a tip Sean gave me is to get a swimming pool noodle as a long sanding block. It is about the right radius and is long to minimize the work. I have sanded down the high points down to fair on most of the hull, except on the keel. There I left as much bog on as I could and filled the valleys. I figure 2 things, firstly this will not only be under water and therefore not visible, but also under antifoul which is not going to be fair anyway as it is so thick, and secondly I figure that as the bottom will not doubt scrape many times I want as much between me and the bottom as I can get. I know it wont make any real difference but a small piece of mind is all.

As I have said the hull is quite smooth to the touch. At this stage that is all I can go on. I have placed straight edges on to check for fairness and the hull feels smooth and flat. Once the white high build is on I am hoping the hull will then also look fair.  A reader has suggested that I need more bog because you can still see the tapes. But this is because the layer of bog is thin. It doesn't need to be any thicker than enough to remove the edges of the tapes, so that you cant feel them if you run your hand up and down the panels. I do it with my eyes closed to see if I can detect the edges of the glass. I fill and sand until I can no longer find the edges this way. As I have said I hope to finish sanding next Saturday. Then on Sunday I will give the hull another coat of resin to seal it, then on the same day, once the resin has almost set I will give the hull a coat of white highbuild.

26 June 2006 Hand Sanding

I managed a couple of hours today but it felt a lot longer. Sanding by hand with the long board is not a pleasant task and I am not as fit as I could be, so there was a lot of resting in between short bursts of work. And I am sure my shoulder muscles will feel even sorer tomorrow. Having said that, I now think I can do this. I dreaded it for a long time and the worst of it is still to come but I am getting used to it.

Before I got to work with the sanding board I marked the waterline again (so I could know what areas would be visible and those that are below the waterline) and also marked the lines on the visible chine. I started with a centreline on the point of the chine and then measured and marked a line 10mm either side of it. I have found that I have a slight incline of the chamfer, that is, it isn't parallel with the waterline. It is 4cm closer to the waterline at the stern than it is at the bow, so it slopes down from the bow. I am not sure if this is how it is designed but I doubt 40mm over 12000mm will be greatly noticeable. It equates to a 1mm drop every 300mm. It will be interesting to see if I get the same result on the other hull. If I don't, I doubt this will be visible anyway and certainly wont be obvious that one hull chine is slightly different to the other. This of course assumes that I have correctly marked the waterline. Perhaps I am out with that rather than the chine. Either way it is of little concern.

Once I had the chine lines marked I sanded the centre of the chine down to the 2 lines either side of it so that I had a flat area within the lines about 20mm wide. I then started sanding the flat panels above and below the chines. Here and there I needed to remark the lines and re-sand the chine flat as the sanding of the panel would impinge on the flattened chine area. I ran my hand along the chine whilst looking away so I could feel for any irregularities. I found 3 over the 12meters. I sanded the panels or sanded the chine to remove the irregularity. I think I have a fair chine. It will change again as I sand more of the panels flat (there are still high spots from the extra bog added but it is very minimal now) but I can adjust as I go. I am quite happy with this chine so far.

The small taste of how hard the hand sanding is a good reason to do the essential work first, the highly visible above waterline outboard side of the hull, then the less visible above water under bridgedeck side of the hull, then the underwater sections last. The reason for this is fatigue and apathy may get the better of you and it is more likely that you will have more energy and discipline at the start so best that you tackle the jobs in order of visibility. One other area not to get to concerned about is the first 200mm of the bow. You still have to make and glass on a nose cone so there is not much point in worrying too much about getting this section perfect as you will be glassing over it again anyway.

The plans instruct you to not be too fussy about the underwater sections and I can understand why. They wont be seen so why waste valuable energy on something that is not visible anyway. I am not saying you can leave it completely but I am not going to be anywhere near as discerning on the underwater and under wing sections. I may decide to use the power sanders to finish the sanding of the re filled low spots on the underwater sections, we will see how my energy and discipline is holding out. I also still have to sand the rounded underwater chines, again I may just use the orbital. Until the weekend I get to rest again at work. Who would have thought that work would be a rest from your hobby!

Time Spent: 67.00 Hours

Total build time so far: 444.00 Hours   Total Elapsed Time: 9 Months 4 weeks

July 2006 logs