The team came back from spring break ready to cut and place the styrofoam blocks to fit in each end. According to the rules and regulations, the flotation must be within 3 feet of both the bow and stern. The foam block was created by cutting several cross sections in plan view and securing them together. The pieces were first cut using the workshop’s band saw and shaved down using a rasp to fit into the shape of the canoe. Finally, a cross section piece was placed on the inside to act as a smooth wall going from the bottom to the top of the canoe. To place the foam down, a thin layer of our mix was placed on the canoe where the foam blocks would be installed. The foam was then covered by concrete and the reinfrocement was tied in on the top. Lastly, more concrete was added to cover the reinforcement and create a smooth finish.

The team began the construction phase this month before Spring Break. The epoxy-coated mold was prepared by covering a layer of carnauba wax to allow for easier removal of the finished canoe. A total of 5 mixes were made using a wheelbarrow, a hoe, and measured out materials in 5-gallon buckets. A trough was made in the middle to where 2/3 of the required water was poured. Once mixed, the rest of the required was poured in to complete the mix. Each batch required about 15 minutes of hand-mixing.

Once the concrete was ready, the team used gloves and trowels to place down the concrete starting from the middle of the canoe towards the ends. The team placed down a 1/4″ thick layer followed by the fiberglass mesh and finally another 1/4″ layer on top. The thickness of the layer was checked using a marked nail with a 1/4″ and 1/2″ lines.

The total process took about 6 hours to complete. The team covered the canoe with wet burlap and a tarp to maintain the moisture throughout its curing process. The team will come back to cut and place the foam ends and cover it with concrete.

Bobby contacted the foam company to order a laser-printed, styrofoam, female mold. The company used the CAD drawing exported from the FreeShip model of the final hull design to cut the shape into several blocks of styrofoam. The turnaround time for the mold, once ordered, was 2 weeks to make the mold in Ohio and 2 days to ship it to TCNJ. Bobby and Jeremy picked up the mold in the Decker Mail Room on February 27th. The mold came in two wrapped bulks as seen below.

With the help of a TCNJ maintenance worker, we loaded the mold into a TCNJ van and made two trips to deliver it all to STEM where the canoe will be constructed. The mold was unpackaged there and was reconfigured to the actual shape as shown below

The team is eager to start the construction process and begin mixing the final concrete design

Before the end of the fall semester, we spoke with Mike Steeil about what materials and supplies we needed to transfer over from the Armstrong lab to the STEM building as Armstrong hall will be closed for renovations. Over winter break, the team discussed the plan for the spring semester and more specifically about the construction of the canoe. We compiled a list of what we already have and what we needed to order. We needed to order a bag of type I cement, elemix, carnauba wax, fiberglass mesh, and other miscellaneous supplies to start construction. Insulation foam was also orderd to be fitted into the ends of the canoe for flotation. The materials were ordered to the Ewing Home Depot for pick-up. While the team waited for mold to be delivered, we began practicing our final mix design in the mixing bowl to ensure the right proportions.

Jeremy has been in the process of performing a structural anlysis of the canoe under the most critical loading condition to find the maximum compressive and tensile stresses. These stresses will help determine the design strength of the final concrete mix that the mix design team should achieve. The critical condition consists of 4 paddler loads conservatively assumed 200 pounds each acting at 20%, 35%, 65%, and 80% of the canoe’s length. The self-weight of the canoe and the bouyancy load is parabolically distributed with based on the changing width and geometry with respect to the length of the canoe. From this loading condition, the shear diagram was developed to determine the moment diagram. The moment diagram was found by integrating all of the shear equations between each of paddler loads. The maximum positive and negative moments will be analyzed and used to find the maximum compressive and tensile stresses.

The Mix Design team has come closer to a final mix over the past month. With their most recent trials, they have achieved multiple mixes that float in water. Mix 8, 9, and 10 have proven to be the most successful in terms of floatability. It is important to note that all of the mixes are in compliance with the 2019 ASCE Rules and Regulations, especially the use of 25% aggregates, discluding microspheres and cenospheres, and mineral fillers.

Mix 8 has an average compressive strength of 252 psi, with a specific weight of 60.11 pcf. This design is very close to the specific weight of water and proved to be more risky and difficult when placing the cubes in water. The team believes a slightly lighter mix will increase the floatability while maintaining the integrity of its strength. Mix 9 was significantly below the specific weight of water, with its own specific weight of 51.11 pcf. It has a very low compressive strength of 68.67 psi. This mix is extreme, and the team can afford to make it heavier in order to fulfill the need for a higher compressive strength.

Mix 10 is still curing in the water bath but was measured to have a specific weight of 55.8 pcf. However, there were major air gaps seen in some of the cubes when removed from the mold, which can make the specific weight appear less than it is in reality, and decrease the compressive strength. The cubes did float in water, so recreating this mix and further testing would be needed to determine more accurate properties. The team has high hopes for Mix 10 in regards to increased strength when compared with Mix 9, as Mix 10 was made to mimic Mix 9, with the addition of the cementitious material Silica Fume, a cement that increases strength.

As the team narrows down their design, modifications to the past few mixes, particularly Mix 8 and 10, will be made in order to determine an accurate specific weight, and maximize both strength and floatability.

The Hull Design team has been conducting research in hull design shapes and softwares for the canoe. All of the shapes of the canoe used in the past competitions were outlined including straight or flared tumblehome, flat, shallow-arch, or round rocker, and stern or shallow v-hull.

Another aspect of research included which software to use in order to design and analyze the stability and resistance of the canoe. The software will allow us to test different designs and see which would have the most beneficial properties. A total of ten softwares have been analyzed by comparing their positives and negatives. From the softwares, we have selected Free!Ship.

The research found on past winners of the ASCE National Canoe Competition in the past few years will serve as testing grounds for us to see which is the most ideal software to use. Bobby and Jack plan to analyze several hull designs in order to provide variety and see which has the most beneficial aspects.

Two weeks after the Mix Team let the cubes cure, the team went in to test their strengths. It was predicted the second mix would have the highest compressive strength, as the first mix’s aggregates were too large for the mold, making it difficult to fill with the other materials and multiple aggregates, and the third mix’s aggregates were run through a #4 sieve and would have less strength.

The three cubes for Mix 1 had a compressive strength of 845 psi, 821 psi, and 831 psi, leaving that at an average of 832 psi. Mix 2’s cubes resulted in compressive strengths of 738 psi, 643 psi, and 655 psi, with an average of 679 psi. Lastly, Mix 3 had an average strength of 639 psi, with individual cube strengths of 634 psi, 666 psi, and 616 psi. The team concluded that Mix 1 was the strongest due to the larger aggregate sizes.

In the upcoming week, the Mix Team will be testing cubes using various admixtures and researching possible lightweight materials, as the mixes previously made, although strong enough to support the team members, would not be able to float in water. Less dense mixes will need to be tested in order to narrow down the design process.