Friday, December 21, 2012

Short days, long nights...

 

December, as usual, is a tough time to get a lot done. Short days, long nights, and a plethora of social obligations conspire to keep me from the shop. However, I've steadily plugged away, a strip here and a strip there, and I'm down to the last three pieces. I'm very ready to be done with the planking and looking forward to getting a workout with the flexible long board I just spent half my life savings on. I spent the other half on epoxy and 6 oz glass cloth.

 
A final decision had to be made regarding the transition at the chines. The bottom is 3/8" thick, but the side planking is only 1/4" thick. Additionally, the angle varies at each station, so a rolling bevel is required at the chine. My solution was to add a 5/16" thick strip, with the rolling bevel on one edge, to the bottom. The other edge of this strip is square. This approach assures no compound angles are required where the planking intersects the bottom.

 
The planking gets a little easier to apply at bottom as the strips get shorter. However, one must be very careful when cutting to length as the strips must fit snugly to avoid any gaps

 
View of transom with all strips applied. She's really starting to look like a boat.
 


Next up, fair the hull and add the skeg.
 
 
Happy Holidays!

Thursday, December 20, 2012

One strip at a time...

 

The Hull Truth


One thing I love about the melonseed is, aside from the flat bottom, the boat is all curves. While I love the look of a lapstrake boat, I wanted the hull to be smoother and more flowing. A smooth hull should enhance the subtle curves that make this boat so visually appealing.This is the major reason I'm going with strip planking. I also wanted a boat that looks good but doesn't require the level of care a traditional wooden boat would. So, I'll fiberglass the hull inside and out, paint the outside, and leave the interior bright.

October 2012


I'm ready to start planking at last. Most folks start at the shear and work back to the bottom. I'll do the same. The first strip is square on one edge with a cove on the other. This puts the cove pointing upwards which makes glue application easier. I'm using Titebond III which has a slightly longer set time then the traditional formula. I found the longer set time helpful when the weather is hot and I'm scrambling to get everything in place before the glue goes off. Also, Titebond III is the most waterproof of the Titebond formulas.

It is a common practice to use staples or brads as temporary clamps until the glue dries. This approach allows for quicker application of the strips but has some drawbacks. Foremost, it creates a vast number of holes that must later be filled and leveled. (a big waste of time) The filled holes will be visible under a bright finish. (ugly!!!) So I decided to keep the holes to a bare minimum. My intentions were complicated by my choice of wood, mahogany is much stiffer and more difficult to bend than ceder. As I've mentioned before, I worked professionally as a cabinet maker, so I have a fairly extensive collection of clamps. This project has taught me you never have enough when it comes to boat building. As I began planking I knew there would be clamping challenges.

One of my other hobbies is guitar making, also known as lutherie. Guitars, like boats, have a lot of curves and therefore present similar challenges during assembly. Over the years I've learned the value of bungee cord in guitar assembly. The nature of bungee makes it very useful for providing clamping pressure in a very controlled way. It is soft and will not damage the wood. At some point it became clear to me I could use bungee cord instead of staples or screws. I acquired some 1/2" poplar dowel rod which I cut into 4" pieces. Then I drilled holes in the stations, inserting the dowel rods through the stations so there is about an 1 1/2" of rod on each side. The dowels are used to secure the bungee cord and will be relocated as needed to provide clamping pressure in the appropriate places.

The first strip establishes the shear line so I decided this would be a good place to use temporary fasteners. I used #8 pan head wood screws for this job. One screw at each station should keep things in place until it's time to glass the hull. I quickly developed a routine for strip application. First, a bead of glue in the cove, not too much, just enough to get a little squeeze out. I start at the stem because this is where most of the twisting occurs and therefore requires the most attention while clamping. I secure the strip at the stem with a spring clamp and work my way to the transom using the bungee cord and other clamps as necessary. I keep a wet rag on hand to wipe away the extra glue. Care must be taken to make sure the strips remain tight to the stations as planking progresses.

 
The bungee method is a bit slower initially, but saves time in the long run. And, no ugly holes! A cabinet makers spring clamp at the stem is just the ticket.

 
This angle clearly shows how the dowel rods are used to secure the bungee cord.

 
Very little pressure is required at the transom.

 
As planking progressed it was necessary to add a few temporary fasteners at station 1. Lots of clamp pressure is required here as the strip twists towards the stem.

 
On work days I would try to get at least one strip glued on each side. Hopefully more on the weekends. At the end of October I was almost to the halfway mark.
 
 

Building the Centerboard


The centerboard for this boat is roughly 18" wide at the pivot end, tapering to around 7", and is 45" in length. The plan calls for 3/4" material covered with glass. I'm using mahogany again, surprise! I created the blank from 18 - 1 1/2" x 46" x 3/4" pieces laminated with marine epoxy. The centerboard will be weighted with about 5 pounds of lead to keep it from floating. I purchased the lead online from Roto Metals. The lead will be melted, poured into a slot in the centerboard, and covered with a wood lid.

 

November 2012


More strips and more creative clamping.



 
 
The bevel on the stem changes as you approach the bottom. Some builders suggest it is a best practice to wait and adjust the bevel as you go, I agree.
 
 
Two pieces to go and some interesting angles to deal with.


 
More on the way....
 
 
 

Wednesday, December 19, 2012

Getting started...

Welcome! My name is Tim Crawford and I'm building my first boat. The boat is a 16' version of the melonseed skiff, originally designed for duck hunting in the 1880's. The melonseed was first documented by historian and boat builder Howard Chapelle in the 1930's. Chapelle plans can be purchased from the Smithsonian for $15. http://americanhistory.si.edu/csr/shipplan.htm  I'm working from plans drawn by Marc Barto and available for purchase at the Wooden Boat Store.  http://www.woodenboatstore.com   Barto offers two sets of plans, a 13 1/2' version based on the original boat, and a larger 16' version. Both plans include full size mold, stem, and transom patterns, eliminating the lofting process. I chose the 16' version as I expect to use the boat for two person overnight camping trips and such.
 
 
The smaller boat uses a sprit rig as pictured above. For the larger boat Barto specifies a stayed gaff rig, with 90 square feet of sail.
 
I picked the melonseed primarily for its size, classic looks, and reputation for sailing capably in stiff winds. My wife Annette and I live on the east slope of the Rockies and will be frequenting high altitude lakes and reservoirs with constantly changing and often unpredictable winds. The sail plan calls for two reefs and I suspect I'll be using them. Another reason I chose the melonseed is she rows well. I'm not into motors and I'm also lazy, so easy to row is an important attribute. Lastly, but not least, she drafts about five inches and should weigh in at less then 350 pounds.
 

Fall 2011

 
Our boat building journey began after a trip to Washington state in the fall of 2011. We spent a few days in the San Juan Islands and then headed south to Port Townsend, home of the annual Wooden Boat Festival. We missed the festival by a week, but many participants were still in town and we enjoyed walking the docks and gawking at the beautiful boats. The possibility of building our own boat was not something we had ever discussed, however, it was soon apparent we were bitten by the boat building bug.
 

When we returned home I began the process of picking a boat. An old friend suggested the melonseed and I liked it immediately. In fact, I had seen a superb example of the 16' melonseed in Port Townsend without realizing it. This was the 'American', an impeccably crafted lapstrake version built by Dave Toner. At the time I had no idea I was looking at a melonseed.
 

 

Spring and Summer 2012

 
With plans in hand I began the process of making room for the project in my garage. I was a professional cabinet maker for a number of years and already owned most of the basic tools required for a project like this. I also had some 8' x 5" square beams, an essential in the cabinet shop, on hand. I used four of these beams to create a very solid strongback. The strongback is not a place to skimp as it provides the foundation for hull construction. It should be very solid and straight. I used metal horses to put the strongback at the right height so to work comfortably while assembling the hull. Comfort = productivity and general well being. I've seen folks working on the floor, but they are young have yet to destroy their knees and backs.
 
The Barto plan set includes full sized plans for the molds. The shapes provided are a half section of the boat. My plan was to create half section templates from 1/4" material and use these templates to fabricate the actual molds, assuring the molds will be symmetrical. I used transfer paper, available at my local art store, to transfer the plan lines to the 1/4" sheet material . The material I used was a combination of plywood and MDF, whatever I had on hand at the time. If you must purchase, MDF is the least expensive. I band sawed the shapes and smoothed the edges, carefully checking my results against the drawing. This is not the place to hurry as the accuracy of the molds will determine how much work will be needed later. For the molds I used 3/4" material, whatever I had in the shop. I cut each mold slightly over sized with my jig saw, then I screwed the half section template to the mold and routed the final shape using a flush trim bit. This boat requires 12 molds placed at 14 5/8" intervals.
 
 
The strongback was carefully leveled before attaching the molds. Mold placement is critical! Check and recheck.

While fabricating the molds, I also worked on the stem, transom, and bottom. The stem for this boat is really two parts, an inner stem and an outer stem. I chose to laminate these pieces using Honduras mahogany. I had some 8/4 mahogany on hand and I love working with mahogany. I created a solid jig to bend against. I don't advocate the approach I've often seen used, multiple blocks set at intervals. This technique too often yields lumpy results. Take the time to make an accurate and solid jig.
 
   
I used marine grade epoxy, thickened appropriately, on the stem parts. There will always be some spring back when the piece is removed from the jig. Compensation for spring back is often built into to the jig, how much is largely a matter of experience.

 
 
I laminated the stem parts in two steps, using wax paper between, so to avoid the more common practice which requires band sawing the pieces apart afterwards. The completed inner stem was trimmed to length and temporarily screwed in place.
 

The transom, like the stem, is Honduras mahogany. I used 5/4 material to finish at 7/8".

 
The plans specify marine plywood for the bottom or keel plate. I opted again for Honduras mahogany instead, laminating 3/8" x 13/16" strips to create the blank. The bottom is over 13' long, so I first had to scarf the pieces together to obtain the required length.
 
 
The bottom was hand planed and scraped to its finished thickness before shaping.
 
 
Bottom shaped and ready to go.

 
The bottom is attached to the stem with a half lap joint.
 
 
Western red cedar is the preferred wood for strip planking small boats. It is very light, rot resistant, and easy to obtain in the Rocky Mountain region. On the negative side, red cedar is brittle, soft and splintery. I don't enjoy working with it. By happy chance I found a local source offering 4/4 Honduras mahogany in 7' and 8' lengths for only $4.99 per board foot. This mahogany was light in color (not an issue) and light in weight (a big plus). At that price I could hardly resist. Honduras mahogany is a pleasure to work with, stable, strong, and it finishes beautifully. One of my favorite woods! The limited length meant I would have two scarfs on most pieces. Lots of extra work but worth it in my opinion. The hull will weigh more, but that really isn't an issue for me. 
 
The process of scarfing and machining 86 - 16' long strips was quite a chore. Most folks use a bead and cove to accommodate the curve of the hull. In my opinion this is way preferable to the rolling bevel approach because it allows for much easier alignment and 30% more glue surface.

 
Machining the bead and cove. 

 
By the end of August I was almost ready to begin applying strips. The last phase of preparation for planking involves fairing the molds. This turned out to be a major chore. The molds are 3/4" thick and must be tapered appropriately based on the location and taper of the adjoining mold. I spent quite a few hours on this and I'm glad I did. This essential step assures smooth results when the planking is applied. Use a batten to check your work and remember time spent here will save time and grief in the long run.

Fall 2012

 
September arrived and it was time for a break. We headed back to Port Townsend for the 2012 Wooden Boat Festival. The festival was a gas and quite inspirational. So many boats, so little time. We returned home with renewed enthusiasm.
 
 
More to come soon....