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.
