Bowsprit and Backing Plate Removal
You can see some light rust on the plate in general but if you look all the way forward or down on the rebar you can see heavy rust. Also, if you look forward you can see the bolts sticking down without nuts. For me to have peace of mind before sailing off-shore I wanted this thing to come out and either be replaced with a stainless steel or bronze plate . . . or I may go with a completely different design and then a reinforcing backing plate won't be needed at all. Cape Dorys are well built boats. But, I don't see the logic in using mild steel in a place that is going to be exposed to saltwater, especially located in a place that you can't inspect or perform maintenance. In fact, water had entered this compartment via the hull deck joint under the bowsprit that was sealed only with 5200. This seems to be the one real major engineering fault for this boat.
Installing the Bobstay Fitting
Designing, Building, and Installing the New Bowsprit
Other than removing the engine and filling in the propeller aperture, changing the bowsprit design is the most radical change to the boat. My plan is to incorporate a more traditional bowsprit--square on deck between the sampson post and the gammoning iron then round and tapering to and slightly beyond the kranze iron. The new bowsprit will put the tack two feet further forward than the original 18" platform style bowsprit, which I never liked. I thought the original was ugly and looked like it was an after thought. The new design, which I worked on last spring, will add about 45 sqft of sail area. It will move the center of effort one percent further forward of the center of lateral plan. The percent of CE forward of CLP is referred to as "lead." My references for undertaking this somewhat frightening task is Skene's Elements of Yacht Designs and Chapelle's Yacht Designing and Planning. As I have mentioned before, the advantages of moving the tack of the headsail forward will be to reduce weather helm; add sail area improving light air sailing performance; and reduce the sheeting angle for the headsail.
I ended the day with a call to the Port Townsend Foundry and talked to them about kranze and gammoning iron options. They walked me through what I will need to do to help them get the castings right.
First, I ran it across a 12" jointer and then through a 24" planer taking it down to 3 7/8" X 3 7/8". I left it 10' long for the time being. Next, I drew out the design of the bow sprit on the blank. Because the sprit only projects forward of the stem 3 1/2' I want to make sure the proportion is right to the eye. If I make it 5" X 5" it will look huge and out of proportion for it's length especially given the somewhat slender line of the Far Reach. But, it has to be strong enough for the job. I have done some reading regarding column compression loads for different species of wood to better understand the engineering requirements. Based on my research, combined with what I have sketched out, I think the right dimensions will be around four inches on each side (at the gammon iron). This size will keep the bowsprit below the bulwark which will improve the profile of the boat. An added benefit is my windless will straddle the bowsprit without the need for adapter plates.
Because I want the sprit to follow the sheer of the topside, vice be parallel to the water, I first I cut a 2" taper on the bottom of the sprit between the butt and where the gammon iron will be located. A parallel sprit looks good on some boat styles but I think it would look odd on the Far Reach. Because the deck is arched up, the center of the deck gets progressively higher relative to the sheer as one moves aft of the stem. In fact, at 4' 4" aft of the stem the centerline of the deck is 2" higher than the adjacent sheerline. So, I either must elevate the front of the bowsprit or lower the back end for the bowsprit to follow on the same line as the sheer . . . thus, the tapered cut on the bottom side of the sprit. The max dimensions of the bowsprit occur right at the stem, where it passes through the gammon iron. Starting just forward of the stem I cut four tapers and carried them forward 36". From that point forward, about 12", I cut a straight four sided 2 1/2" square projection--this will eventually be rounded to serve as the sleeve the cranse iron to slide over. For this design I plan to leave the bowsprit square between the gammon iron and butt but will round the taper from the gammon iron forward, to include the sleeve for the cranse iron.
In the picture to the right I let the aft end of the sprit run wild. If this were to be the bowsprit design, it would be cut about a foot shorter. To support this bowsprit, a large (5X5?) sampson post would extend down through the deck and be bolted to the forward side of the bulkhead that separates the anchor locker from the forward cabin. The sampson post would have a mortise cut into it and a tenon would be cut into the aft end of the sprit. The sprit would "float" in the gammon iron and the crase iron would "slip" over the forward part of the sprit resting on shoulders cut into the taper. The advantage of this style of sprit is it sits about 1/4" above the deck so air gets under it. The only holes in the sprit are for the anchor rollers, so it is less prone to rot. Because there are no bolts securing the sprit to the deck it can be easily removed for yearly maintenance which reduces the likelihood that rot will go unnoticed. It remains to be seen if this is the right design for the Far Reach.
So far I am pleased with the design. It may be that after I round the taper that it will look to small. But that will provide me information I did not have before.
The next thing I did was to make a larger "spar-makers" 7-10-7 gauge. I described this tool in an earlier post when I made a round handle for my carpenters tool box. But a quick recap is that the 7-10-7 stands for ratios that essentially use the formula for a Pythagorean triangle to allow a square sided spar to be marked, then shaped, into an eight sided spar. From there it is simple to shape to a 16 sided spar and ultimately sanded round. One angles or cocks the gauge until both outside pins are against the spar. Then you pull the gauge along the spar leaving two pencil marks the length of the spar. You make these marks on all four sides. If you build the gauge correctly all the lines are an equal seven "units" of distance from the edges of the spar. Then you use a bock plane or power plane and take the corners down level to the adjacent lines. At that point the spar is eight sided. After making the gauge, I ended the day by marking the spar for shaping tomorrow.
I started off by working on the nose of the sprit. You can see the progression of work in the photos below. The hand planes will only go up the loom of the spar to about 2 inches or so from the lip. I have to use chisels for the last three inches of the main sprit and the nose part. This is where the spoke-shave would help. The idea is to plane flat the corners between the lines, made with the 7-10-7 gauge. I checked to make sure I was planing flat by laying a ruler across the area being planed. In the photo you can see the gap under the lower portion of the straight edge. That means the upper part has to be taking down further. After I worked the nose I moved to the main part of the sprit to be smoothed. It took about 40 minutes per side. With more practice I am sure I could do it in half the time. I reaped the benefits of having spent a few hours during the summer "tuning" the bottom surface of the planes as well as the irons on Japanese water stones. They were cutting very nicely today. I used a coping saw to cut some "scallops" to refine the edge at the juncture of the tapered part of the sprit and the square part that will be positioned in the gammon iron. When I finished with the rough work I took the bowsprit up to the boat to see how it looked. This particular sprit is 39" long from the stem of the boat to the location of the cranse iron. That is 21 inches further forward than the original 18" on the Cape Dory 36. I have discussed how I came to this number in other posts now located in the "bowsprit" project. I should have made more progress today but I had to take time out to go to the store to buy more coping saw blades after the only one I had broke while cutting the "scallops." I was amazed at the amount of shavings produced. The planing was not difficult and was in fact very enjoyable, though my shoulder is sore tonight.
Tomorrow, I will 16 side the sprit then start sanding it round. I will not spend a lot of time sanding since that is not the purpose of this task. This is just a mock-up to see if this is the design I want. I need to get the basic dimension right so I can build the pattern for the gammon iron to be cast in bronze.
In the top photo I placed my windlass on the sprit and took a 6x6 scrap (which is much bigger than the actual sampson post will be) and set it at the heel of the bowsprit just to get and idea how everything would fit together. It looks right to my eye. Once 4" tall bulwark is installed, the stays fitted, the anchor is installed, and other hardware is in place it will blend right in.
This morning I emailed some photos of the sprit and a drawing depicting my thoughts for a gammon iron design to Port Townsend Foundry in Washington State. I then called and spent some time talking with Pete Langford about the design and he described the process for casting a custom gammon iron. He was very helpful and encouraging. He said he would send me some photos of various patterns depicting what I will need to do if I want to make the pattern myself. Pete said it is somewhat complex but he would walk me through it if I wanted to attempt to make the pattern. Otherwise, I would make a series of templates and they would make the pattern. In the meantime, I will contine to work on the interior.
To escape the heat I decided to spend the day working on the bowsprit in the coolness of the air-conditioned wood shop. The overall shaping and tapering of the mock-up bow-sprit was pretty straight forward when I did it last fall. Click here for more info on tapering the spar itself. However, this was my first attempt at shaping the end of the spar to fit a predetermined taper--in this case the taper on the inside of the kranze iron.
It was not very pretty work but it was a good opportunity to learn the basics of the required techniques. It's a little rough in some places and the knots in the #2 yellow pine I used for the mock-up caused some difficulties. But the fit seems to be pretty good. I used a mallet to drive it on. The real sprit will be Douglass Fir and will of course be completely clear of knots. Plus, the pattern makers rasp will be less aggressive than the carpenter's rasp I used today and of course I will be more patient for the final product, with more sanding, etc. I think I could also wax up the inside of the kranze iron and slater some thickened epoxy on the area where the kranze iron will go and then drive the kranze iron on to made sure I get a good fit. This would make sure there are no voids or uneven spots. It's something to consider. In the meantime, it's time to get back into the boat, 100 degree heat or not.
Building the Gammoning Iron Pattern
The pattern will be used by Port Townsend Foundry to cast a custom designed silicon bronze gammon iron (or gammoning iron if you prefer). The gammon iron is a metal fitting attached to the deck at the stem head that the bowsprit passes through. Usually, the tack of the staysail is secured to a tang on the top of the gammon iron. That is how this one is designed as well. The gammon iron is essential to mounting a removable and more conventional and slightly longer round tapered bowsprit. The original plank style bowsprit was bolted through the deck and could not be inspected without a huge and often destructive effort. In fact, the original bowsprit was through bolted in eight places to a mild steel backing plate (another one of those odd Cape Doryisms that defy reasonable explanation). The backing plate was pretty rusted due to water intrusion through the bolt holes and through a gap in the hull-deck joint at the top of the stem. I removed the bowsprit and the backing plate in the early phase of the rebuild. Click here to get the background on that project. The new bowsprit will start off square with the heel set into a solid wood sampson post about 4 1/2' abaft the stem-head. As the bowsprit passes through the gammon iron (at the stem-head) it will become round and taper to the end where a bronze kranze iron will be fitted over the end. The head-stay, bob-stay, and whisker-stays all terminate at the kranze iron. The new bowsprit will be relatively easy to remove and be about 18-21 inches longer than the original bow sprit but weigh about the same. The new gammon iron will allow the terminal end of staysail stay to move forward the same distance the headstay moves forward. The longer conventional style bowsprit will provide a better mount for the manual windlass, a proper lead for the anchor chain, help to reduce weather helm, increase sail area, and slightly reduce headsail sheeting angles.
As I said, I have never built a pattern for a bronze casting . . . and this one was complicated for a beginner. It was slow going. Pete Langley, founder and owner of PTF, was wonderfully generous with his time patiently walking me through the many steps and monitoring my work through pictures I emailed to him. The type of casting that will be used to make the gammon iron is called the "loose sand, method. This type of pattern is called a "split pattern." One side is called the drag while the other side is called the cope. A very brief overview of the steps are explained in the text associated with the below photos. For more information about pattern-making and metal casting click on the pdf file to the right. The document was produced by Port Townsend Foundry.
In between work on the gammon iron I applied a couple of more coats of varnish to the cabin sides. One of the coats came out poorly and I had to sand, and sand, and sand to fix it. It was quite a bit of fun. The most current coat developed very tiny bubbles shortly after it was laid on. This is only on the cabin sides and not the staving. Not sure what is causing this. I have done some research and there are lot of different views. It's not the wood. It started with the fourth coat. It is definitely not the brush or roller. I don't think it is the temp. I vacuumed the night before, did an alcohol wipe down that night and again the next morning. I led the application with a good quality tack rag. Hmmmmm . . . . this is a mystery. Epifanes says it sounds like dust. I am not so sure but I have some time to sort it out. I changed mineral spirits though (I add a capful to 10 oz of varnish. So maybe I should go back to the other mineral spirits.
Installing the Gammon Iron
First, I checked the fit of the gammon iron. I want the bowsprit to follow the sheerline of the boat. That means it needs to tilt up about 4 degrees--the same angle as the last 6 feet or so of the deck as it runs up to the stem. The old plank style platform rose at about 1 degree. I never liked the way the original bowsprit "stuck out" nearly horizontal to the water while the sheer swept up. Did not look pleasing to me. Of course the new sprit is longer than the original by about 2 1/2' for a total of about 42 inches forward of the stem. Of course the real advantage to this gammon iron is the sprit will not be bolted to the deck so the chance of rot should be greatly reduced. But, I digress . . . .
Third, I sanded off the old primer with 40 grit on and RO sander where the fairing needed to take place so the new epoxy could adhere to the older epoxy laminate and previous fairing, vice hooking on to primer. The heavy grit will improve the mechanical bond of the new fairing.
Fourth, I mixed up two batches of West Epoxy heavily loaded with 404 High Density Filler. I added small amounts of 407 silica to improve its ability not to sag. The 404 fillers are mineral based and according to West Systems serve as a better "heat-sink" than straight 406 and reduce the likelihood excessive exothermic heat that could damage the epoxy. As Tim Lackey pointed out to me, the bronze itself would also help dissipate the heat. Once I mixed up the thickened epoxy I spread it out on a fairing board to reduce the heat build up and give it a little more pot life.
Fifth, I trowled it on to the deck and stem of the boat.
Sixth, I pressed the gammon iron down onto the bow and braced it into position with a purpose built 2x4 braced between the center post on the boat shed that separates the two "barn doors" and the gammon iron to hold it in position.
Seventh, I spent about 20 minutes fairing in the epoxy "squeeze-out" and another 20 minutes wiping up epoxy dribbles and smears with an acetone soaked rag.
Once I was satisfied the gammon iron would stay in place, I ran some errands. This evening I took my dead blow and tapped on the gammon iron kind of gently testing to see if it would come loose. It popped right off. There are two small voids. Overall, I am very satisfied with this first step. Tomorrow, I'll wash off the amine blush and continue fairing probably switching to 407 micro balloon.
After working on the gammon iron I applied pipe-dope to the two scupper sea cocks that had been just lightly screwed together. I also cut the scupper hose to fit between the cockpit scupper drains and the tail pieces on the seacocks. I ran out of time so I'll continue to work on them tomorrow.
This morning wiped off the release wax with a rag soaked with Interlux 202. I used the two rag system: one rag soaked with 202 to wipe across the wax and a dry rag to wipe it up. Interlux 202 is very strong stuff with naphtha and other nasty chemicals so I wore my full face respirator. Next, I scrubbed the whole faired surface with water and a 3M medium maroon scrub pad and wiped it dry with paper towel. Then, I applied two coats of thickened epoxy as part of the fairing to support the gammon iron. I used West Epoxy with 407 and a little 406 stirred in to make it non-sagging. I think it is starting to look like it belongs there. As I mentioned yesterday, the bulwarks will make all the difference in the world. I applied the first coat and about and hour later, when it was firm but not hard I applied the second coat to fill in some of the dips and hollows. After it cured later in the day I repeated the water and scrub pad wipe down and then sanded the whole thing. It will require a little more work but with luck it will be finished tomorrow afternoon.
Installing the Bowsprit
The rest of the time has been spent installing some small pieces of trim and the final shelving in the port locker. I have been working through a short check list of items to accomplished. I ordered bulkhead mounted compass for zone one-- A Richie BN 202 Navigator. I learned that you can by a separate globe for different world zones for about 2/3s the cost of a new compass. Then, you just swap out the globes. The new mast will be ready for pick up next week. I'll have to pick it up (an interesting adventure in and of itself I suspect) then prep it for painting. As soon as we have the mast painted and assembled with the trysail track, whisker pole track, and all the fittings we will start taking down the boat shed. While we are working on the mast I will start splicing one end of the standing rigging. We plan to splice the other end on the boat after the mast is installed and lined up with the halyards. There is a lot to be done for certain but with the exception of the sails the Far Reach could be ready for the water in about a month. I think we will wait for final deck fitting installation after the rig is in the boat so we can see where best to locate some of the fittings. The final list of things is not too bad . . . I continue to add a few here and there but I already plan to cut the list off as soon as the boat is ready for launch. We will finish some things later. I need to go sailing . . . and soon.