Removing Constructional Stretch

Constructional stretch occurs as a byproduct of the splicing method. When you open the weave to bury the tail, you also cause the line to shrink in length. When tension is applied to the line, this looseness in the weave will work itself out in the form of stretch.  

It may seem that a new stay is stretching like crazy, but this is all due to the splicing process. Removing this stretch before installing the stay will greatly decrease the amount of time it takes to setup new synthetic standing rigging. 

To begin, you need to stretch out all your newly spliced stays and line them up end to end. You will tie the end of the last stay to a strong anchor point, the other end to a strong pulling device, all the stays in between will be tied to each other.  

I like to use a massive tree with a strong root system as my anchor and a heavy truck as my pulling device. With the stays tied between the truck and the tree, I can create a lot of tension on the stays to remove most of the constructional stretch. 

Once everything is setup, the process of removing the stretch is very straight forward, simply drive away from the tree and have the synthetic rigging stop you.  The truck I use weighs around 7,000 pounds, so stopping it requires some serious force. This strong yank will quickly remove any stretch that might still be present in the splices.

The process of removing the constructional stretch is very straight forward, but knowing when you are done is a little less obvious. There are a few ways to check and see if the constructional stretch has been removed, some are more obvious than others.

The first way is to milk the splice from the eye splice into the stay. If there is constructional stretch present, the outer weave will begin to bulge. Working these loose strands into the stay will greatly remove constructional stretch. If you can't get the outer weave to bulge, most of the constructional stretch has been removed.

Another way to remove the stretch is to push up and down on the stay while it is pulled tight by the truck. I push the stay down with my foot in the middle of the length where my force will induce the most tension. If there is constructional stretch present, the tight stay will become slack when I release my foot. If it becomes slack, move the truck forward to tighten the stay again and repeat the process.

Both of these methods involve close inspection of the stay, and a lot of walking. Walking from the truck to the splices and back to the truck over and over takes a lot of time. Instead of all this walking, an easier method is to simply drive the truck forwards and backwards repeatedly. The sharp yanks induced by the truck will remove the stretch in a very short amount of time. After a few yanks, you can feel free to do the first two steps and evaluate if any stretch is remaining in the stay. 

The easiest way to evaluate if any constructional stretch is present is to look at the thimbles. A new thimble that has never been loaded will have an opening near the throat. After a thimble has been loaded with a lot of tension, the throat will close and the ends of the thimble will touch.

After a few pulls with a truck, you will see the thimbles starting to close. Simply repeat the process until all the thimbles are closed, then evaluate the stays by milking and pushing down in the middle. If all the thimbles are closed and there is no remaining stretch, the stays will remain tight after testing them with your foot (pushing down in the middle of the stay and releasing to see if the line goes slack). If there is any stretch in them, simply do a few more pulls with the truck and re-evaluate the stays.

Long Days

Maddie and I have decided to set sail for the Caribbean during 2017, this means that Wisdom needs to be ready to go by then. Being ready to go means that the long list of major projects I want to finish need to be completed. This should not be a difficult task as all of these projects fall well within my comfort level, the problem is finding enough time to carry out all of these projects.

I work during the day as a dentist, when I get home to the boat, I begin working my second job as a rigger. This work will carry on into the night until I go to sleep. As you can see, there is no time available for the boat projects that need to get done.

At the moment, I am re-rigging an Islander 36 as well as doing smaller jobs on other sailboats. As soon as I am finished fabricating the rigging for this yacht, I can resume work on our boat projects that need to be accomplished.

In the mean time, Maddie sees me in the morning and late at night when I get home. The long hours in between are consumed with work. Maddie and I have discussed the lack of time that we spend together and we are in accord with the situation. We both know it is temporary and for a good cause. Once we set sail, we will spend all our time together because we will be cruising once again.

The rigging jobs take priority over the boat projects because the rigging jobs bring in money while the boat projects cost money to finish.

My longest day occurred on a Thursday, when I started my day at 5am with installing a clients in-mast furling mainsail, then I went to the dental office to see patients. When I got home I continued to fabricate the stays for the Islander 36, finally finishing my work at 10pm. It was a very long day, but a very productive day. Knowing that this schedule is temporary helps me make it through these kinds of days.

Whoops!

So, the faying surface of the keel was not square to the keel sides. The stem however was cut into the keel set parallel to the keel sides. The result is a wonky frame in need of a change of plans.

I could either cut a new stem with an offset finger that would connect into the finger joint and keep the bow plumb or I could cut the bottom of the stem off and attach the stem to the keel on the same faying surface as the frames (and inline with the frames). 

If I cut the bottom of the stem off, it would be best to set the bow at a slight angle that way the force is better transferred through the knee and with less strain on the stem. This option allows me to keep my current stem and not need to remake the stem. 

I am able to do this because the stem was cut much longer than necessary, allowing me to cut off the bottom portion and set the stem at an angle on the keel. Since the stem is being pushed back, I will need to reshape the knee to fit in front of the first floor. 

The advantage of building a dinghy is you can change your mind about things as you go, as long as you cut your timbers longer than you need. It is very easy to cut off excess, but not as easy to make members longer.

Since I will not have a finger joint anymore to support the stem, I need to wait for the bronze fasteners to arrive that I will use to connect the stem and stern post to the keel. These large 4 inch lag bolts will tie the wooden structures together and resist corrosion over the hard life of the dinghy.

Dinghy Assembly

Now that the frames are glued and screwed to the floors, it is time to assemble the backbone and frames.

The floors are fastened to the keel via bronze screws along with Titebond III to secure the floors to the keel. After everything was set and finished, I noticed that Station 4 was setup backwards on the keel! While the glue was still wet, I loosened the floor screw and rotated the floor, re-tightening it once the station was oriented properly.

To make sure the floors are set square to the keel, I rested a square along the side of the floor and the perpendicular along the length of the keel. Keeping everything square, I drove the bronze fastener all the way down, tightening the floor and squeezing the excess glue out of the interface between the faying surface of the floor and keel.

The stem was also glued in place along with the knee using no fasteners. Fasteners would interfere with later cutting and shaping that will occur in these areas, so they are forfeited for the time being. After the final shaping is completed, the stem and knee will be fastened securely using bronze fasteners.

The next steps will be to secure the stringers which will strengthen the frame up significantly and begin to transform this project from a whale skeleton into a boat!

Frame Fastening

The dinghy will be finished bright, meaning that all the wood will be varnished and oiled and no paint will be used. This means that all the small details will be visible for years to come and won't be hidden away under a coat of paint.

The floors and frames, along with their interfaces will all be visible and therefore needs to be finished in an aesthetic way. The frames and floors were all cut out and test fitted, making sure that the flare on them was appropriate. Now the sanding begins!

The frames and floors are first run on a belt sander to take off all the saw marks and pencil lines. Once the surface is smooth and flat, I transitioned over to hand sanding where I was able to round off any hard points that will project into the hull. The faying surface that will face the planking and keel was left sharp, as these areas will be adjusted later as the build process continues.

The frames and floors were lined up in the squares and pilot holes were drilled through the frames and into the floors. Bronze fasteners were also driven in to verify proper alignment and fitment.

Once everything was dry fitted and tested, it was all disassembled. The faying surfaces had a liberal amount of glue applied to them and the frames were then screwed on. Clamps were not necessary as the force from the screws provided enough clamping force squeeze out any excess glue and intimately mate the faying surfaces. Glue was also placed down the screw holes, further locking the fasteners into place.

For finishing touches, all the screw heads were oriented vertically. There is a debate about the proper orientation of the screw head, if the slot should be vertical or horizontal. The argument for vertical and against horizontal is that the horizontal slot can collect and hold water, where a vertical slot will let the water run right out.

This is very nit picky, but I chose to orient all the screws vertically. More important than the orientation of the slot is that they are all uniform. When the screw heads are all haphazardly arranged, the entire construction looks disorganized and chaotic. Orienting them all in the same direction makes everything flow better and feel more at ease. It also looks like the craftsman took the time to make sure all the details are covered. 

Excess glue was wiped away and allowed to cure. Now the floors and frames are united and ready to be mated to the keel. Construction of the dinghy is progressing quickly!