- Removing the Old Bow Sprit and Backing Plate - Relocating the Bobstay fitting - Designing and Installing the New Bowsprit - Building the Gammon Iron Pattern - Installing the Gammon Iron -Shaping the Bowsprit for the Kranze Iron
Bowsprit and Backing Plate Removal
This picture depicts the infamous Cape Dory bowsprit "backing plate." The Cape Dory owners website is filled with the angst of Cape Dorians that have this steel plate in various stages of rusting decay. By reviewing the forum on the website I was able to get a good feel for what I was up against. The best information on removing the backing plate came from Fred Bickum's website http://www.sbastro.com/FeNIX/. You have to look around but he describes in general terms how he got the plate out of his Cape Dory 28 FeNix. The website is accessible via the Cape Dory Sailboat Owners Association http://www.capedory.org/cdownersweb.html
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.
Before enlarging the anchor locker
Before I could removed the bow sprit and backing plate I had to be able to crawl into the locker. The locker in its original configuration was too small to do anything other than stick your head in there and see that, yes, there is the rusty backer plate. So I cut the opening larger with my jigsaw. I clamped some wood strips to serve as a template so I would be able to cut a straight line. This made the opening big enough but I still had to remove the center divider to have enough room to work. I used the skill saw and the saws-all to get most of it out. Part of it was tabbed in and I had to carefully use the saws-all to cut the tabs. Because of the tight angle between the divider and the hull nothing else would fit in there. Once I removed the center divider I was able to crawl into and wedge myself in the anchor locker. From there I removed as many of the nuts as I could that fastened hardware either through the bowsprit--stay sail boom fitting, bronze tack for the stay sail, the downhaul block for the asymmetrical spinnaker--or to the bow pulpit. Once I removed those I cut the exposed ends off the (6) 1/2" bolts that secured the bowsprit to the backing plate. There are eight bolts but the forward most two did not have nuts. Not sure why but boy was I glad they were not on there.
After enlarging the opening
Bow without the bowsprit
Getting the bowsprit off was just plan physically hard work. Despite researching how to do this and putting a lot of thought into it I could come up with no way to finesse the removal of the bowsprit. I had earlier removed all the bungs and bolts. Then using a half dozen 12-14 inch long oak wedges and a heavy mallet I drove them in between the deck and the bowsprit in a leap-frog manner. I started at the front and then worked my way down both sides. I used my Dremel Multi Tool to cut some of the adhesive around the wedges but it would only go under the bowsprit about 1 1/2 inches. I then used a small pointed handsaw about 14 inches long to cut through the adhesive from one side to the other between the front of the bowsprit to where the wedges were. Then I advanced the wedges forward and cut the adhesive up the closest wedge and continued on till I got to the base of the bowsprit. It probably took about three hours of hammering and sawing to get the bowsprit off. All but a 3x4 inch section of gel coat remained intact. The bowsprit appears to be in good shape. I was pleased it came off totally intact. It is in good enough shape to clean up, revarnish, and reinstall but my plan are to go with a different style of bowsprit. Any wood other than teak and I think there would have been a lot of rot in it.
Well here it is. The Cape Dory bowsprit backing plate. I refer to it as "the beast." You can see it's a 1/4" steel plate with rebar welded to it and it weighs about 25 lbs. The side toward you is the underside of the plate. The pointed end, facing to the right, goes into the bow of the boat. The bracket hanging down on the left side was bolted to the vertical 3/4" plywood anchor locker divider. The rebar was laid against the stem and fiberglass tape ran through the slots glassing it in place to the hull.
Once I had the bowsprit off, I laid out all the tools I thought I would need--a Dremel with a right angle cut-off adapter, a roto-zip with a cut-off wheel, a 4 1/2" angle grinder with a cut-off wheel, a saws-all with a steel cutting blade, wood wedges, a mallet, a hammer, etc. I knew backing plate was only glassed in across the rebar. It was a tight squeeze but the Dremel was the best tool. With a full face respirator on, I was able to cut the fiberglass tape off pretty easily. But the plate was really wedged in there. I couldn't pull down on it because the rebar was tight against the stem. I pounded some of the wooden wedges in between the backing plate and the mishmash above it. The mishmash is about one inch thick and it fills the void between the arched forward deck and the flat steel plate of the backer plate from the back end all the way to the bow. I beat on it with a hammer for a while and was not sure what to do. I could barely wiggle it. I determined that the only way it would come out was to be pulled straight back--not down or even side to side. So I hooked my come-a-long up to it and ran the cable back through the boat and secured it to a 2x4 laid across the companion way hatch. Then I ratcheted it as tight as I dared and beat on it some more with the hammer. I took the come-a-long off and thought I would finally have to resort to cutting it out in pieces with an angle grinder. I cut on for about a minute but could see this approach would take hours. I picked up my hammer and beat on it a couple more times and it suddenly just fell out into my lap. Simple as that. Boy was I happy.
This is what the anchor locker looks like with the backing plate out. There was quite a bit of rust that came off the plate while I was beating on it with the hammer. Probably 2-3 cups worth of flakes. Some pretty big. Note the mishmash. I think I'll leave it in there. There is a very smooth layer of fiberglass cloth on the bottom side lightly tabbed to the hull. It is a little ragged on the aft end but I think I will sand it smooth and add a nice fillet of epoxy there and leave it to reinforce the deck. I'll need to do some grinding to smooth out where the vertical anchor locker divider was tabbed in as well as the backing plate.
Installing the Bobstay Fitting
It was time to glass in a new backing plate for the bobstay after removing and discarding the original aluminum plate last year during the destruction phase. This is another one of those weird Cape Doryisms--bronze bobstay fitting, SS bolts, and an aluminum backing pate. I don't understand that why they did that. Nonetheless, I started out with final sanding on the backing plate for the bobstay fitting that I cut from some G-10 yesterday. I used my Bosch Jigsaw and a carbide tipped blade. The carbide blade is critical. G-10 is very hard stuff as I had learned when I cut the backing plates for the through-hulls last summer. I cut the backing plate 17 inches long and about 2 1/2" wide. To fit into the narrow part of the stem of the boat I had to cut a bevel on each side.
Beveled edges on the bobstay backing plate.
G-10 Bobstay backing plate glassed in.
I cleaned up the edges with the bench top sander, and then used a sanding block with some 60 grit to scuff it up on both sides. I rechecked the fit. I also sanded the stem area with some 40 grit, vacuumed, and did a thorough acetone wash down. Next, I mixed up a bunch of epoxy and thickened it to peanut butter consistency with colloidal silica and some 404 High Density filler that I am trying to use up. I toweled it into the stem area and on the backing plate and pressed it into position. I cleaned up the excess with a plastic squared off stir stick.
Next, I drilled the holes yesterday after installing a new G-10 backing plate a couple of days ago. I moved it about 13 inches lower on the stem than it was originally installed. This was necessary to get a better angle on the new longer bowsprit. I got all the hardware together but found it was difficult to get the bolts to go in. Not sure why since I didn't have any trouble with it yesterday when I did a quick test fit. So, I just kept at it and with a little tapping the bolts finally went in. I went up in the boat and installed the washers and nuts and used a ratchet to tighten the nuts down to make sure everything fit properly. Then I climbed back out of the boat and got the camera to take a picture. As soon as I looked through the view-finder I noticed it looked funny. The thing was on upside down!! A very professional job. Well that explained why the bolts were hard to install. So, I had to go back up into the boat, take off the nuts and washers, and then reassemble. This is not the final install though. After the boat is painted I will make the final install with caulk and bronze, vice the original SS bolts.
The 1/2" X 4" silicon bronze bolts for the bobstay fitting arrived today These will replace the stainless steel ones that originally fastened the bobstay fitting to the stem of the boat. When possible, I'd like to keep bronze with bronze. It was hard to find bolts with shoulders that I could buy individually. Others I found had to be purchased in a box of 25 or something like that. What would I do with 25 1/2" bronze bolts? . . . and they are not inexpensive. Each bolt will have a washer, lock washer, and two nuts. These are also the extra heavy duty nuts.
Designing, Building, and Installing the New Bowsprit
Building a 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.
The first step is to build a mock up bowsprit to see how it will look and to see if I have the skills to build one I will be satisfied with. A few days ago I bought four 10' long 2X8s at Lowes. The straightest, least expensive, wood I could find, and it was all pitiful, was #2 Southern Yellow Pine . . . lots of knots. Anyway, after working on the tiller this morning I jointed one edge of each of the 2X8s and ran them through the planner to mill them down to about 1 1/8" thick. Next, I ripped them to 4 3/4" wide on the table saw. Next, I laid them out so the grain would be running in opposite direction to even out the tension of what will be a four plank laminated "post" that will serve as the blank for the bowsprit. To save time and money I used regular Tightbond yellow glue. Nothing fancy . . . this is a through away after all. Finally, I glued them up across a couple of saw horses and threw on an assortment of clamps.
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.
The next morning I unclamped the blank for the bowsprit. I knocked off excess hardened glue then did the best I could running it over my 6" jointer. I don't have a lot of in-feed and out-feed tables so this was a tricky undertaking with such a big heavy piece of wood. I got it close as close I as could then loaded it in the truck and headed over to base wood shop.
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 first in a series of mock-up bowsprits.
"This is like deja vu all over again." After deciding that the first bowsprit was a little light in design I glued up another one today. This one will be 5" square at the widest point where the sprit passes through the gammon iron. Everything else will remain the same. I glued this one up pretty much the same as the last one. Wednesday I'll take it to the base hobby woodshop, run it over their jointer and through the planer. Then I'll draw the pattern on the blank and cut it out using the big bandsaw. I need to get the design nailed down now so Port Townsend Foundry has time to cast the gammon iron.
Another blank for a second bowsprit mock-up.
After the glue on the bowsprit was hard, I unclamped it and took it to the woodshop on base and cut the pattern out with a bandsaw. I decided to make the widest part 5"X5" (where it passes through the gammon iron). I also made it a few inches longer just to experiment though I think 36" forward of the stem will be about right. Anyway, it is much bigger than the old bow sprit though it is only one inch wider on each side. Take the cross section of the widest dimension of the first sprit I made for example: 4x4=16 sq inches of surface area. Take the second one I made: 5"x5"=25 sq inches. That's a difference of more than 9 square inches which makes the second one more than 50 percent bigger than the first one. That means it can handle much more compression, all things considered equal. But, it is also heavier. The first sprit weighs 23.5 lbs, while the second sprit weighs 35.5 lbs.
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.
The second mock-up bowsprit blank next to the first one.
A spar makers 7-10-7 guage.
I spent most of the next day making the bowsprit 8 sided in preparation for rounding the tapered part of the spar that projects forward of the gammon iron. I wanted to do this with only my jack plane and smaller block plane to improve my skills. I also used some chisels since I don't have a spoke-shave, though I have one on order. Though it takes longer to do this with hand planes I have more control plus the shaving go on the floor instead of all over the shop like they do when using a power planer.
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.
The mock-up bowsprit.
Image:
The 5" X 5" square sprit trimed down to 4.75" X 4.75" square.
A few days ago, after building the second mock up bowsprit around a 5"X5" loom I thought I had the right size. But I kept looking at it and it seemed a little too big. This was after I built the first one at 4"X 4". So, I decided to experiment. I basically took it down 1/4" so the sprit is, at it's widest point 4 3/4" X 4 3/4". It's only 1/4" but it made a big difference. The tapered part of the sprit is a little more slender. The whole thing looks better. In the top photo the sprit is 4.75" X 4.75" and the photo below is the sprit at 5"X5". It's a little hard to tell the difference in the photos but if you look closely, especially where the round taper begins just forward of the square part of the sprit, you can see the difference.
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.
5" X 5" square.
It takes a lot of effort to go out to the SRF on a day like today. 100 degrees. It's just plain hot . . . anyway you want to describe it. Recently, there have been no visions in my head of sailing in the clear sun bathed waters of the tropics . . . instead I'm sailing north through a green sea, reaching along the coast of Ireland. "It's was crisp and cool this morning. We ran the refleks heater to take the chill out of the cabin. Breakfast was oatmeal, toast with marmalade, fruit, and a steaming cup of coffee. But the sun is up now, bright in all his glory." Whatever it takes to keep going.
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.
Practice on the mock-up bow sprit.
When I shaped the mockup bowsprit last fall I drew the taper out and the "step-down" shoulder for the kranze iron (I didn't have a kranze iron at the time, so I made a "SWAG." I used a band-saw to make those cuts and then used a 7-10-7 gauge to lay out the lines for shaping it to 8 then 16 sided. Then, I spent some time sanding to make it round. I used the sprit to get the dimensions for the gammon iron that I made a pattern for and then had cast in bronze. Click here for more info on the gammon iron.
What I wanted to accomplish today was to practice how to taper the end of the sprit to accommodate the taper on the inside of the kranze iron. The opening is 2 1/2" wide at the aft end and tapers down to 2" wide over the 4 3/4" length of the kranze iron. I used my calipers to determine the diameter of the sprit where the aft end of the kranze iron would ride on the sprit and did the same for where the front end would ride. I used a compass to make a circle on the front of the sprit to serve as a reference point as I shaped the forward 8" of the sprit. Next, I clamped a wood straight edge to my back-saw to control the depth of the saw cut. Next, I made two cuts: one for where the back of the kranze iron (wider diameter) and one for where the front end (narrower diameter) would sit. From where the front edge of where the kranze sits to the end of the sprit I made a series of vertical cuts all the way around the spar with the depth controlled by the wood straight edge on the back saw.
Next, I used a chisel and mallet to remove this excess wood, thinning down the sprit forward of the Kranze iron. I then used a rasp and file to smooth the initial shaping cuts on the forward most part of the sprit. I just kept working it till I could slide the kranze iron over the tip. I put the kranze iron on backward to help me determine when I had removed just the right amount of wood to that part of the spar with the front edge of the kranze iron would lay on the sprit. Then, I carefully began to rasp from this smaller diameter back to the step-down, or shoulder, where the aft end of the kranze iron would sit. The best tools seem to be a carpenter's rasp and a 10" file. I ordered a "pattern makers rasp" from Lee Valley tools earlier in the week but it had not arrived so I went with what I had on hand even though the rasp was much more aggressive than I would have liked. I used a small straight edge to make sure I was getting a straight even bevel over the length of the taper.
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
19 Feb 11 I spent the last two plus weeks building the pattern for the gammon iron. Since I have never built a pattern for a bronze casting this was slow tedious work. The result was a daily battle of inches instead of miles. So, I decided to wait to post the project to the website until it was complete.
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.
All that is left to do is add the styrooam peanuts, the top slotted wood panel, the styrofoam top, tape it up and mail it to the foundry.
The gammon iron arrived yesterday. PTF did a nice job. Looks just like the pattern I mailed in early March. I wasted no time getting started. The fairing has to be complete, before I can paint the boat. It looks kind of big sitting out on the end of the boat all by itself but it will blend end once the 4-5" high bulwarks are installed. Here is the sequence I followed (pictures posted in the photo-gallery below):
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 . . . .
Second, I heavily waxed the bottom and edges of the gammon iron with paste wax to serve as a release agent.
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.
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11 May 11 I was able to work on several projects today. I am pressing to get the boat ready to paint. The summer heat will be here in a few more weeks and that will complicate the painting.
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.
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Today I used Interlux Water-Tite fairing compound for the first time. Saves a lot of work since it is pre-thickened. It's also a 1:1 ratio so its quick and simple to mix up. The nice thing about it is I can use as little as I need. I use the pump system with West System and sometimes I need a lot less than I can get with one pump.
Installing the Bowsprit
This is the latest picture of the bowsprit modification. The sprit is just a mock up made from lumberyard pine glued up with yellow glue. The real spirt will be made of laminated doug fir glued up with resorcinol adhesive. It will also increase the width and height of the sprit by about 3/8" to fill up the gammon iron. This was not an accident but intention when we made the pattern for the gammon iron. I felt the cross section needed to be a little larger. I decided not to use a sampson post as I just did not want to cut a 6"x6" hole in the deck. The bronze heel-cup will be through bolted to a G10 backing plate that will be laminated to the underside of the deck. I think the heel cup fits with this style boat better than a sampson post. In the picture the windlass is sitting on its mounting plate in its final position but is not bolted through the deck. I'll do that later. I have had it sitting there for a couple of weeks just getting use to it. I like the way the sprit and the windlass look together. I designed the sprit and the windlass to work together as a system with the chain locker directly below the windlass down pipe.
