Fairing, Roof, Sheeting points

Just too hot.

Posted by Paul

Steel sheds have a fatal flaw for boat building in our ever warming climate. They trap heat, no amount of whirly birds on the roof can dissipate the heat fast enough, and the elevated position of the boat is such that the higher up on the boat I am working the hotter it is.

As I showed with the digital thermometer last month, if it reads 38 degrees at floor level, it is 10 degrees hotter on the boat roof. And it is so hot that pots of bog must be small or else the plastic container is hot before I am finished mixing it and the surface I am applying it to is super heated so that the bog is starting to exotherm as it goes on. And the thicker the mix the faster this all occurs. I have had countless pots start smoking on me.

So work speed is frantic so as to get bog down before it spoils and this leads to overheating of my body which results in lots of sweat and little achieved and short working days. I can only stand 3 or 4 hours of it. Last week I was feeling heatstroke and had tunnel vision for about 10 minutes.

But I am not complaining.  All of that was just to say, progress has been slow. Not much to show for the 3 weeks of the year so far.

dust tracks

Before we get to what I have been able to achieve, no-one noticed what was in the background of some of my pics last month. The guys I share the shed with got the contract to repair 2 of the Extreme 40 cats that had raced in Sydney in the final round of last season, before they ship off to Singapore for the first round of next season first weekend in Feb. They had 2 weeks to fix the various dings and respray 4 hulls (2 cats), one white one navy. (I have a fine coat of navy dust all over my boat as a result and found these curious tracks in them in the above pic with my footprint for scale. My guess is a lizard). For those that dont know about Extreme 40’s google them and check out the youtube vids, they are like the formula one of sailing races, not quite Americas cup but close. I could not mention them last month but now that they are gone I can.

xtreme 40 1 xtreme 40 2 xtreme 40

Extreme 40’s are a one rule field of about 15 teams with boats designed to fit into a 40 foot shipping container, even the masts are 2 piece so as to fit inside. There are about 10 rounds each year in different locations around the world. Teams include Red Bull and Alinghi and the crews and helmsmen are the who’s who of Olympic and AC sailing. Flying hulls is not accidental at this level, it is strategy.

So as not to get my dust all over there work I took a couple of weeks off while they were in the shed. Jo and I spent a wonderful week in Hawks Nest on Port Stephens. I spent a day snorkelling at Nelson Bay and hand feeding the bream in the marine park there. Less than 5 meters from shore in waist deep water, hundreds of plate sized bream and other species. It begs the question what came first the marine park status protecting the fish that were already there (and if so, would this protection if extended to other areas result in fish there too) or do the fish congregate in such numbers because they are protected there. Either way I have no objection to the new marine parks being proposed all over the country (but opposed by vested interests). Port Stephens is definitely on my list to explore once the boat launches.

After a week of wishing the boat were finished in such a beautiful setting it was back to  the reality that it isn’t.

grinding back fairing compound grinding back fairing compound 1

I left off having glued the sheeting point arms and legs in but not yet glassing them in. First task was to remove the fairing compound so that I could glass to the underlying glass. In places the bog was 4mm deep, which is helpful because it means that the glass I lay down wont cause too much of a lump that has to be faired back out again, the smaller the lump the less bog and fairing required. There will still be some lump, because I laid down 5 layers of glass, 4 x uni 1 x double bias but because I tapered the layers it should fair out ok.

As the pic shows, I fanned the uni out so that the layers met on the face of the sheeting arm but splayed out over a wider area of the roof. This keeps the height of the glass down and spreads the load out onto the roof and also helps with the directions the loads might go as the boom works through its arc and is sheeted at various angles during the various points of sail. There are also 3 layers of glass on the underside of the arm and inside of the leg. The are has more glass than the leg by about 3 layers overall. I also tied the layers of glass together with a tape wrapped around the arms and legs like a bandage to contain the uni. All in all another 5mm of glass rounding the arms and legs out to 50mm. I peel plied them rather than try to bog them wet on wet, its just too hot in the shed to work that long, but mostly because I plan to glass steps in so bog would just need to come off again for the glassing, easier in this case to peel ply then bog it all later once the steps go in.

I had cardboard templates of the steps I wanted. The top step is the sheeting arm itself. The middle step fits between the sheeting leg and the cabin side and I didnt want it to protrude aft of the sheet arm profile so the only consideration in creating the shape was the curve at the front and that was also constrained by the window so it pretty much set itself. The bottom step mirrors the middle step shape but had to end by about the middle of the sheet leg because any further aft and it would interfere with the fall of the sheeting line to the deck. It does extend further forward than the middle step though so it ends up about the same size.

I experimented with a narrower bottom step so it did not protrude into the walkway as far and would have a smaller underside wrap and look much smaller but in the end I favor a really easy footfall and the feeling of having the entire foot fall on the step. The middle step is glassed on 2 edges so it wont need any bracing other than that, but the bottom step will need either webs or a wrap around, most people go the wrap around as it looks so much neater and although it looks like more work is actually less.

roof steps glassed in 1 roof steps glassed in roof steps glassed in 2

To create the underside wrap I made a cardboard template. After a few cuts to trim it down to the size and angle that I liked I had my shape. It is almost symmetrical but the curve is subtly different top and bottom so I marked which curve was which when I transferred the shape to duflex. I cut kerfs into the inside of each one. I forgot that there is a flat area in the middle and kerfed all through the first one, which made shaping it a little difficult. To remedy this I glued a flat block back in to retain the flat area and did not kerf all through the middle on the second one and it fit much easier.

roof step underside template roof step underside template 1 roof step underside kerfed duflex

I spread a wet glue mix into the kerfs, buttered the top and bottom edges (which had been bevelled to shape during the dry fit) and glued and glassed the wrap arounds in. Because I screwed the tread to the wrap I could not bog on wet glass I had to peel ply, then when the glue is set I can fill the screw holes, round the edge and glass it and bog it then.

roof step underside dry fit roof step underside dry fit 2 roof step underside dry fit 1

roof step underside glassed roof step underside glassed 1

I am running out of Qcell and will have to buy more, but in the meantime I still have some west fairing compound. I prefer the qcell because it goes on smoother and created far less pin holes, and now for a third reason, it seems to have a longer pot life using the same resin. But because I have it I decided to use it as a first layer. It builds good volume and is very light weight and sands ok (if you sand it within a couple of weeks of it curing, I have some older bog that has been on the boat over a year and it is hard as rock!) so other than having to make much smaller pots to avoid smoking it, it will be ok.

In winter, the rule of thumb with this stuff is to mix it until the gloss is off the resin mix so it looks like peanut butter, but in summer you cant add that much powder without the heat starting through the container before mixing is complete on all bu the smallest pots. I have a bunch of 4 litre ice cream containers thinking if I can mix more each time it means I get the job finished sooner, with 2 litre pots I might mix 5 or 6 on each job, so with 2 litre I might get away with 2. Not in summer, I threw 3 smoking pots out with a quarter of my mix still in them. So I lost about a litre of resin and powder. No great loss but very frustrating to feel it gelling on the trowel and hardening in the container as I desperately try to slap it on the job as fast as I can, sweat dripping into my eyes which I cant wipe because I have bog all over my gloves……ah stop complaining already, no-one said it would be easy.

sheeting point and steps first bog 2 sheeting point and steps first bog 3 sheeting point and steps first bog 1

sheeting point and steps first bog sheeting point and steps first bog 4

Actually there is one advantage of summer heat. Bog is hard enough to sand next day. In winter you might have to wait 3 or 4 days for it to be ready to sand. I am not yet fairing, I am still what I call shaping, so I used an orbital sander to get the top off the bog, then a long board to blend the new bog with the existing high built faired areas. I do have a little height where the layers of glass overlap and have build some height to the glass so I will need to widen the area of the second bog run to feather that height out to an imperceptible edge. Of coarse with so many angles and nooks I could only use the orbital on the larger flat areas. The rest was hand paper or the very thin small board. There are also a few very low areas that need more fill rather than more sanding.

sheeting point first bog sanded sheeting point first bog sanded 1 sheeting point first bog sanded 2

sheeting point first bog sanded 4 sheeting point first bog sanded 3

There are areas under the arms right up against the cabin and under the middle step that still need to be sanded and many areas on edges that need more bog so I ran the second coat today using just Qcell. I also took the opportunity to fix the top of the starboard window that had a few minor and subtle kinks in the top edge, so I ran a thin layer of bog over it again to try and clean that up a little more.

sheeting point second bog 1 sheeting point second bog 3 sheeting point second bog 2

As you can see from the 4 pics above, it is already almost faired back to the original roof profile. Of course with all bog and sand, it takes a number of runs to get it right and I expect I have a few more to go before I can reapply the high build and make it all look the same.

I am pretty happy with the sheeting arms overall. Yes they are ugly protrusions that spoil the boats sleek lines, but they are necessary to the bi rig set up regardless of what sail type I go for. And the steps work better than I had originally anticipated. You can climb up and down facing the direction you want to go. I was worried that one might have to come down the steps backwards but they work like normal steps, we will see if that changes with a pitching boat.

Still no word at all on the wing sail idea but the idea (of soft wing sails) seems to be gaining momentum so I am still hopeful that this idea will work for me. Another thing I have learned is that the sheet loads of a wing sail compared to a similar sized regular sail is much less (also much less load on the masts) so that reassures me that the sheeting points I have just installed are capable no matter which way I go.

The heat doesnt look like letting up for weeks yet so dont expect too much progress until March!

You May Also Like