This post picks up exactly where this post http://yikes.com.au/2012/09/16/catwalk/ September last year left off. You know, some stuff happened in between but we are picking up where we left off on a number of these unfinished jobs. As the Sept 12 post mentions, I made the rails and rungs for a ladder that will sit in the trough of the catwalk (under a lid most of the time, the lid being the real catwalk). Its primary purpose is to swing out onto jetties whenever we nose into a jetty rather than back in, as the base for a gang plank that sits under it when stowed but is over it when deployed and swings out on the same hinge (the hinge being a 20mm stainless steel rod that is also the axle for the front anchor roller) and sit on the ladder to form an entry plank for the bow. Or if we nose into a beach for an afternoon ashore (another thing we did on the same boat that would nose in to our local jetty and we would have to climb up and out a meter to board) we can deploy just the ladder down to the beach rather than having to wade up to our waists and enter from the stern steps that are in deep enough water to float the boat back off. Highly unlikely but I guess also possible would be as a swim ladder at the bow, perhaps if I dive on the anchor I could theoretically climb back onto the boat up the bow ladder, but it would be far easier to swim to the sterns and climb up the rear steps.
So, last September I made the ladder rails and rungs and left them sitting there waiting to be glassed into a ladder. You know how it is, it is a relatively easy job so it kept getting put off. I am still waiting on the rudder bearings (the guy builds bearings the way I build boats!) so here is another little job that I got a bit more work done on.
So first job was to trim the parts to size. The sides not only cut to size but cut into the shape of the bottom of the D section it abuts at the aft end and similarly the forward end abuts the forebeam which a similar but slightly different shape. Then each rung had to be cut to size for the width of the span it would fall at (it starts out 400mm wide at the front and widens to 500mm wide at the deck).
In order to do that I had to space the rungs. I did this twice. Why it took me 2 goes was because I changed my mind once I had it set out the first time. What I decided was that as I mentioned above, the likelihood of ever using the ladder in deep water was unlikely and the spacings that I had the rungs with a bottom swim rung was 350mm which is a little further than a usual ladder. Most ladders have step spacing of about 300mm maximum. Both the ladders in the shed had 290mm spacings. So in order to close the spacing down the bottom step is now about 300mm off the bottom rather than about 50mm. This would put it at about water level rather than about 250mm below surface level. When you try to climb a ladder from the water it is much easier if you can get a first foot on below water and start climbing rather than trying to reach a first step on or nearer the surface. But as I dont think I would ever use the swim ladder function, having the closer steps figured as a better option. (The top rung could not be moved, because of the hinge that has to span the forebeam the top rung has to be as high as possible on the ladder because as it is, it will hang about 400mm from the top of the beam, any lower on the ladder and that top step would be too far to climb over.)
The 2 images below illustrate the change in the rung position. In the first set up the bottom rung was a bit too close to the bottom and contributed to the decision to move them. I could probably still put one more rung back in, in the space it would have been in the first pic, the spacing would be slightly less than the rest of the rungs but that is not an issue. I just dont think I need it. So I had to re jig the rungs which meant they would be a few mm too wide when moved up the ladder so they had to be trimmmed, again no biggie, 30 seconds on the radial arm saw. It didnt take long but its another of those jobs I did twice instead of just once. Never mind.
Whilst clamped on the table I glassed each rung from above it onto the ladder sides using 2 layers of 50mm double bias (450gsm) and let that set. The next day, just for the heck of it, I tried climbing the ladder with just the top of each rung glassed to see if it would take my weight. Risky I know. But not a creak or a grumble. Just a slide because of the slippery base only being about 5mm x 25mm each side. Yep I fell off. No damage done. Anyway, the good news is that with just the top glass the ladder is plenty strong but of course I intend to glass from below as well, including using blocks to further reinforce the rungs.
I have offcuts of duflex or ply below the ladder so that I cut it to the correct length 20mm off the catwalk to simulate the thickness of the gang plank underneath and also a plank above to simulate the lid on top to simulate the finished job. (I cant wait until I dont have to simulate any more). The lid, when I get to make that, will be slightly curved so as to have any water (waves) that may crash onto it roll right off again. The bottom of the trough will have drains because I wont be sealing the lid but the bulk of the water will roll over the catwalk sides because the lid is slightly raised, and overboard between the catwalk and the tramps.
The ladder is glassed but still needs to be cleaned up: sharp edges rounded, glass tapes feathered out and ladder faired. I an not going to go overboard with the fairing of the ladder. It just needs to be safe, so no jagged edges or fibres, and painted so that it cannot degrade (epoxy is not UV stable) and then I will apply non slip to the treads.
Next job will be to figure out a hinge. I will make that out of glass. I originally thought that perhaps stainless steel would be better but I dont think it would be any stronger. It needs to perform in a number of ways, it must be strong when hung from both vertically (when climbed from below) and horizontally (when used as a gang way) so the catwalk has to be able to swing all the way over the beam and hang from it. Still not sure if I have made the plates glassed to the forebeam big enough to enable the ladder to hang. I think I have but not 100% sure until I try it. I will make both sets of hinges (ladder and plank) and then I will make the plank and attach it to the hinge and attach the ladder to its hinge, then finally the lid. It too will be hinged, to the side of the catwalk. There will also be a narrower lid over the anchor chain trough hinged to the other side of the catwalk so that when at anchor, both lids can be down for a full width surface and an uncluttered deck (the chain will to below the lid and down through the catwalk and a bridle snubbing the chain (the chain is slack and the bridle takes the weight of the boat). A rope will attach to the bottom of the ladder for pulling it back onto the boat. When aboard but at a public jetty pulling the gang way back aboard will make the boat more secure (uninvited guest cannot just walk aboard as they may be able to if the boat was backed in to the jetty).