Assembling and Fitting the Daggerboard Trunk Casing
Make sure that prior to placing the daggerboard trunk into the boat you have it assembled and have fully sealed the daggerboard trunk casing with the appropriate resins, reinforcing the seams with fibreglass tape.
There are two different plans/methods for the daggerboard trunk. One daggerboard trunk option is slightly wider and involves cutting through the mid-seat frame. The other design, is simply placed between the two frames. The advantage of placing the daggerboard slightly forward, is it allows for better upwind handling. The larger width, also means it is possible to slightly reduce the aspect, and therefore draw less water. The second option is easier to install, and allows for more forward legspace.
The downside to installing the trunk through the midseat frame is that it can be tricky, as it involves cutting out a small section out of the frame already in the hull for the trunk to pass through. In addition, it also takes up more room and leg space, although it can make a convienent forward seat
Both plans are included in the zip files - The first step in either option is to assemble the casing. However, before assembling and installing the daggerboard casing in either case is to select a resin system, and fibreglass cloth.
Choosing Your Resin
The first thing you need to do is decide what type of resin/taping method you want to use on your hull. The good folks at Industrial Paint and Plastics were great in providing sound advice. These guys really provide great customer service and help, and have been instrumental in helping with previous projects over the years including a restoration of a 'Stratford style' Dory and a wooden Sabot.
Industrial Formulators', 51Cure is an epoxy system for people who are looking for the performance of popular epoxy systems that mix at 5 parts resin to one part hardener and want epoxy performance at a lower cost.
Industrial Formulators Inc. is one of the major suppliers of epoxies for industries like construction, electronics, marine, automotive, sporting goods, and hobbies. Their formulations have been used to solve problems and are used regularly in pulp mills, submarines, dams, museums, railroads, and research labs, along with more conventional uses like boat building.
There are several basic polyester resins on the market. While not as strong or as durable as epoxy it is considerably less expensive. Fibreglass resin generally comes in two types, waxed and un-waxed. We used the "unwaxed" variety for greater paint adherence. We used Industrial Paint and Plastics IP140 General Purpose resins which exhibits a moderate exotherm temperature and cure to allow for thicker laminate applications.
Choosing Your Cloth
The next thing you need to do is choose a fiberglass cloth and/or tape. You could buy larger sheets of fiberglass and then "strip" it into 4" or 6" width lengths to be applied as tape. We chose to buy fiberglass "tape" which ran about $1.50/CDN per yard to save the labour on stripping a larger sheet. It took about 18-20 yards to complete the project. There are basically two types of cloth available, chopped strand mat and woven. Chopped strand/surface mat is a material comprised of chopped fiberglass of various lengths randomly dispersed to provide equal distributions in all directions, held together by a resin soluble binder. Chopped strand is commonly used in laminates due to ease of wet out, the good bond provided between layers of woven cloth is comparatively low in cost. It can be hard to fit around corners, but does provide a smooth appearance as the fibres "melt" into the resin. This is commonly used for "all fibreglass" projects as a fiberglass laminate or as a reinforcement in-between layers of gelcoat. I find chopped strand hard to work with, as the "strands" are generally held together by the resin, and can pull apart if you try to "stretch" it across a surface. Chopped strand is generally categorized by "weight per square foot". It is commonly available in a 1oz x 4" Tape or 1 oz x 6" tape.
Assembling the Daggerboard Case
Regardless of the epoxy/tape system your chose, you will need to make sure that your case is well assembled. It is a simple matter of cutting the two sides of the case and then using ample resin, wood screws and glue to hold it together. A little fibreglass tape on the outside of the seams, will also help to seal and give it strength. Basically a 1" x 1" piece of lumber separates the two halves of the daggerboard.
Basic Daggerboard Trunk Assembly
Make sure that prior to placing the daggerboard trunk into the boat you have it assembled and fully sealed. There are two different plans for the size and location daggerboard trunk.
Cutting the Daggerboard Slot
Method #1: Fitting the Daggerboard Trunk Through the Mid-Seat Frame
The trick to the daggerboard slot is to make sure that you place the daggerboard trunk in the boat, and check your fit before you cut through the bottom of the hull. If you plan to cut through the midseat frame using method 1, then measure the middle of the midseat frame and draw a line from the top to the bottom of the hull. Then measure the case, and draw a line on the end of the case from top to bottom along the middle. Match the middle of the case to the middle of the midseat and draw an outline of the daggerboard case, from the bottom of the hull upwards onto the midseat frame. Use a small handsaw to cut out the portion of the frame required to fit the case. You may need to cut along the bottom of the frame, and sand or file any excess material from the bottom of the frame, in a method so as to have a nice clean opening for the daggerboard trunk to sit. Periodically check the daggerboard trunk to the hull, and make sure it makes a flush fit with no gaps.
METHOD 1: Cutting through the midframe
Method 1: Mounting the daggerboard case through the midseat frame.
Make sure before the case is permanately attached to the hull, that you cut a slot.
Cutting the slot - for both daggerboard methods
The next step is to cut the slot for the daggerboard to pass through the hull. The easiest method for cutting the slot, is to trace around the daggerboard trunk, and then make an inner slot based on a 1" gap between the halves. You do this by marking a measurement on both sides that is 1/2" distance from the outer diameter, and on each end, marking a measure measurement that is 1" from the outer diamter. Then you link the measuresments together by tracing a retangular slot onto the bottom of the the hull. After the daggerboard slot is cut, you will want to fair it up with a flat file and some sandpaper.