Crate construction


This crate is for the Shamrock V with a 89-3/4" LOA and the added AMYA 2" to the keel.
1/4" plywood, sanded on one side, 5 sheets
3/4" or 11/16" square pine stock, 108 feet
3/4" quarter round or triangle corner pine stock, 32 feet
1 x 6 rough, 32 feet
2 x 4 rough, 7 feet
1" drywall screws, less than 50
1-5/8" drywall screws, less than 50
2" drywall screws, less than 50
#6 x 5/8 flat head sheet metal screws, 128
1/4-20 steel threaded inserts, 26
1/4-20 x 1" Phillips SS round head machine screws, 42
1/4" standard diameter SS washers, 42
1/4-20 SS nylock nuts, 16
2" metal right angle braces, 4-holes, 32
6" four-hole handles of your choice and machine screw sets to suit, 4 sets
A good quality Polyurethane glue, 8 ounces
30-minute Epoxy glue, optional, bet you have some?
Formica and contact cement, optional
If you are painting:
Exterior primer, 2 quarts
Exterior color, 1 gallon (3 coats)
If you are building a J Boat, you will have the stuff needed.

About the Crate Design
A monocoque concept of frames and stringers was chosen to control alignment and weight of the crate. If care with measurements are used and the frames built in corner clamps, little, if any racking will be needed. The critical set up is that of the four quarter round stringers. However, wood is awful now and some care should be given to selection and cost. The skids will hold the cradle away from the skin of the crate and thereby, provide some crush protection.

However, it was determined that the handles needed to be on the end pieces and this consideration was vacant in the planning. These handles must be on the end for back management, the crate is too wide. The crate was designed to 93.5" inside to provide a buffer of 2.75" combined at the stern and the bow. This was felt to be minimum for 2" foam over carpet at both ends. This ultimately would produce a 96.5" LOA for the crate with the handles included and a task for the 8-foot bed of a truck or anything. Here, the stern end cap will be removed once loaded in the truck to close the gate. Now you was Murphy's Law.

Boats here live in crates wherever they are and then used for shipping when needed. This allows protection to the boat and the convenience of stacking. The Formica is a nice touch if you don't mind the expense. The steel inserts will give good service if Epoxied in place and the fasteners only snug. That is all that is needed as the crate is not waterproof anyway. When you take the time to build a crate, you will wonder how you ever did without one.

Note: This design, crate building and the photos taken was without a hull or boat present. The cradle and crate were built from J boat plan drawings. This was the only safe means of getting the hull from the East Coast to the West Coast. Corrections will be edited here if needed.

The top and bottom pieces are 25-1/8" and the side ones set inside the top and bottom. They are 23-7/8". Make 16 each from the square stock for the 8 frames. The 2" right angle braces were from a major building supply and will be secured with 6x5/8 flat head sheet metal screws. Assemble these in corner clamps to insure they are square.


Crate Skins
5 sheets...sorry, there is a lot of waste. (Build an EC12 crate with the leftovers.)

The bottom is 25-5/8 x 93.5" and will overlap the sides. Cut three this width, however, leave two at the full 96" length. One will be cut into three pieces for the top sections and one will be cut in two pieces for the ends. The sides are 25-3/8 x 93.5" and should be flush with the sides of the frames.

The Skids
From the remaining 1/4" ply, cut two 4" wide strips and one at 14 inches wide.

The Process

Starboard Side
Mark the 25-3/8" side as such and where forward and up is. Mark the starboard side for the frames. The frame alignment will begin flush with the bow then on center at 10, 20, 30, 63.5, 73.5, 83.5 inches and finish flush at the stern. It is suggested that you make a dry run by clamping on all the frames and checking the measurements on both sides of the plywood. Mark both sides of the square stock against the plywood to place the glue and align the frame. You will need to block the bottom side off the floor or table for clamping. Glue and clamp in place. The open center section of the crate is to access the boat in the cradle at the frames of the cradle. This is the only place that foam support should be placed, as it will press downward on the boat where the molded keel can support the pressure.


While this is curing install the 4" side skid plate. Measure from the stern to and cover the #20 frame (about 73-5/8"). Cut two of these. Then cut four pieces 7-1/2" long from the remainder. These will be the backing plates for the lifting handles. You might as well cut the 14" wide skid piece to the same length while you are at it. Determine the height of the widest part of your cradle, including the 1/4" ply skid base, and measure up from the inside of the frames at #30 and #63.5. This will be the center of the side skid. Cut three pieces of square stock that will fit longwise between these frame and against the side skin. Glue one on center to support the side skid and the other two spaced outside this to support and stiffen the side skin.

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Prepare additional square stock on the top and bottom of the side between the frames. These are to support the top and bottom skins and provide a place for the top screw inserts. Glue and clamp all these in place.

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Meanwhile, prepare the skids with Formica if you are going to use it. It was found here that one coat of contact cement sealed the plywood and another provided the bonding surface. One coat on the Formica is fine. When these are shiny dry bond them. You may like to have a helper here to guide on the Formica to the ply. This is not a countertop so if you are off a bit, no problem. However, sand off the edges of the Formica so they will not be abrasive.


Install the 4" wide skid with glue and weight it down for curing. Remember, from the stern forward to and over the #20 frame. Allow all this to cure before proceeding.

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Prepare 4 pieces of 1" quarter round or triangle corner stock that will run the full length of the crate at the inside four corners of the frames. These will give longitudinal support to the structure and align the crate. Cut one to fit at the frames where they are cured to the starboard skin on the bottom. Clamp it and mark on both sides where the frames are. Place glue inside the mark lines and carefully lift it up to the other side at the #30 or #63.5 frame. Align the loose frame to the same marks on the stringer and clamp it. Now go to both ends and align it flush and clamp. Align the rest and clamp. Repeat this process for the other side. Now, glue in the stringers on the starboard side where the frames have cured to the skin. Allow all this to cure.

Port side
Mark the side as such and where forward and up. Complete the process above for the port side skin. Allow all the new parts to cure.

Additional Items
Also glue in a piece of square stock to what will be the top, inside of the wide section on frames #30 and #63.5 and clamp. These will allow support for the center top section and a place for the screw inserts.

The sides can have three 6x1" drywall screws counter sunk from the outside of the ply at each of the frames, if you like. Sand all external places where the glue had beaded or ran.

Bottom side
The bottom piece is the same length as the side. Align carefully and clamp on the ends. Mark the frames on the plywood for gluing. You will need to block the bottom side off the floor or table for clamping. Run a dry test of what procedure you will use. If you can borrow four to six 36" bar clamps, life will be easy.

Squeeze on the glue and carefully align the crate onto the bottom side. Your roommate could be helpful. Clamp the ends. Weight down the crate onto the blocking till the bottom side is flush and mating to the side. Use bar clamps if you have them. Fret with this till all is well.

Glue in the base skid centered over the frames from the stern. Weight this down also. Allow this phase to cure.

The Ends
Cut the bow and stern pieces to fit from the eight foot 25-5/8" sheet that you previously prepared. The measurement is from the top of the frame to the bottom, including the bottom skin (about 25-5/8"). Remember, the top sections will overlap the end pieces. If you have maintained measurement control of the frames and used cabinet corner clamps to assemble them, no racking of the box will be needed. The end opening should be square. Clamp the cut piece on and mark the inside. fuss with this till you have it where you want it. Use these markings to line the piece with square stock on the inside. This will assist in straightening the plywood. A ¼" inside those marks will be good to fit inside the main crate structure. Mark which end is which and the top of each. Glue and clamp the square stock and allow curing.


The crate is ready to close and finish

Install the Ends
Note: Some of the photos here will show the end screw points on the top of the frame. This was determined not to be a good location. This was corrected on the EC12 crates being built at the same time. Hence, you will see some with screw points on the sides of the end frame. This position is far more satisfactory.

Clamping to the top piece of the frame square stock, align the ends to fit. Mark the outside on the sides to show where the 1/4" ply skins are and the square stock glued to them. This is to determine a dead center shot with the drill for the inserts into the square stock. Measure down from the top of the frame 2-3/4" and mark on the sides. Measure up from the bottom, including the bottom skin, and mark at 3"on the sides. These measurements will cause you to miss the angle braces on the frames. The care here is that you want to drill through the ply skin into the square stock so that when the insert is installed it will be centered in the square stock. Okay. Drill a pilot hole at the four locations. Try to get this as square as possible with a hand drill. Four drills were used here finishing with a 5/16" bit. Remove the skins. Was it centered? Good.

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Now, drill the square stock with a 11/32" bit. Tap the hole with a 7/16-14 tap. Install the insert flush with the wood. Loose test installing the end skin with fender washers. You want a nice loose fit so the screws can be started by hand without much tension. Tighten the ends and see that you have a nice seal.

Top Sections
The top sections are cut from the eight foot 25-5/8" sheet that you previously prepared. The reason for three sections is two-fold. You generally need access to the center sections more often than the others. Smaller sections will fit better with less warping of the ¼" plywood. You will have access to whichever sections wanted.

The bow section will cover the end piece and over the #30 frame. The stern will cover the end piece and over the #63.5 frame. The center section will be in between and over the cripple square stock you installed. Measure and prepare the sections with a minimum gap between. It is suggested that you cut the bow and stern sections first and then the center.


Clamp the end sections in place overlapping frame #63.5 so they will overlap the top of the end skin and fuss with this till it is right. Carefully remove the end skin and clamp the top section on the end like you did above. Mark the sections for the fasteners and don't forget the ¼" ply on the sides and the overhang on the end. Like the end caps, mark as needed to dead center the square stock and miss the steel angle braces. One fastener is aligned for the four corners and one on each long side for each section. Pilot drill and work up to a 5/15" bit. Remove the sections and drill the square stock with as above for the insert. Tap and install the inserts. Install the screws and washers. Mark and line where the center section will be. Mark the inside of the sections so that you can line them with square stock later just like you did with the end skins. Remove the outer top sections. Center the center section between these lines and clamp it down. Install the fasteners as above.

It was decided here that lining these top sections with square stock would be arduous and not likely worth the while. It was found that with six screws in each section they mounted quite flat and in time might form without the stiffeners. This may be true of the ends as well but the job is done at this point.

It was also decided to use standard size washer rather than the fender style. The larger washer overlapped the edges of the sections onto each other...oops.

Close the crate with all sections fastened. Prepare a belt or palm sander with 60 grit and go to it. Remove fasteners as needed to do the job. Oil stain or prime for painting. Stain or paint all the sections on the outside that are removable off the crate so there will be no sticking. When all this is cured hard, paint or install labels and markings to the shipper.

Note: If there will be any contamination onto the inserts during this process, the inserts may move by action of the screws. It is suggested that you keep the areas around the inserts clean to prevent any binding of the screw action. If you feel this is a problem, then when finished with the staining or painting, remove the inserts, clean and reinstall with Epoxy on the threads.

6" handles are installed with additional ¼" ply backing where thought needed. The backing could have some glue to adhere to the location. It is suggested that machine screws be used rather than sheet metal screws. These should be backed with fender washers and Nylock nuts installed. The thought is that lifting a crate, with a Shamrock and its ballast within, will approach 120# as a total piece, including the pallet add-on. Lots of handles and strong connections are advised.


Forklift Friendly
Many shippers other than Greyhound require a crate to be set up for forklift movement. The following process is designed so that you can remove the gore when not in use. Likewise, the materials are not finished, generally low-grade and considered to be sacrificial and replaced as needed.


The crate is placed upside down on the table or floor. Three pieces of 2x4 are prepared for the width of the crate. Two pieces of 1x6 are cut to 93-1/2" and aligned over the 2x4s. 2-1/2 drywall screws are used to attach these together. The unit is rotated onto the bottom of the crate and clamped in place. The unit is screwed into the crate at the two frame locations either side of the center 2x4 with 1-5/8 drywall screws. Be carefull not to choose a screw location over an existing fastener. Screw in two more 1x6s over the 2x4s to finished the pallet like structure.


Pick-Up Truck and the Shell
Close but no cigar! The missing thought was the slope of the Leer shell. Oh Well... When the crate returns with the new hull, the pallet will be removed and it will be modified so the window gate can close. This Shamrock needs to be transported to regattas in this crate and this truck. Otherwise, it will be a $42,000 boat! Stay tuned.

For those familiar with the EC12. That is an EC12 crate inside. I cannot print the expletives stated when this photo was passed around.