Brainstorming
Vessel Restoration
Before design was attempted on the adjustable oarlock block itself, the boat which would serve as the test vessel required several repairs and alterations in order to become seaworthy. This phase of the project was crucial, as the effectiveness of the repairs would determine the dinghy’s ability to properly test the model. The design of the test boat would provide several details for the construction of the adjustable oarlock block. Although the block will be designed to function regardless of make or model, the model will be especially well suited to the test model, as the dimensions will taken from the existing oarlock sockets of this model in particular.
The vessel was provided free of charge by Fair Haven Yacht Works. The dinghy had laid along a wall for two decades, overgrown with weeds and covered in accumulated dust. A quick survey of the exterior revealed a small hole in the fiberglass hull, which could potentially compromise hull stability. Aside from minor cosmetic spider cracking and the aforementioned grime, the vessel seemed to be in serviceable condition, at least for the needs of the project. Once removed from the wall, a closer inspection revealed faded a registration tag on the left side of the bow, revealing the boat to have originated in New York state. A sticker on the right section of the stern proclaimed the boat to be a product of “Skimmar Aeronautical.” A search of iBoats.com, using the make and approximate dimensions, reveals the vessel to be a mid-to-late 1970’s “Scalawag.” The “Scalawag” model has appropriate equipment to be rigged as a sailboat, but can be adapted for a variety of uses (iBoats.com). Standard oarlocks enable quick conversion into a rowboat, and provided motor mount permits the use of a small outboard engine. On the test dinghy, oarlocks on the starboard side had been replaced and refitted, presumably due to some damage in the vessel’s history. The wooden motor mount had long since rotted away, destroyed by the passage of twenty years. Clearly, however stable the boat appeared, work was required in order to provide for the fitting of an adjustable oarlock block.
The original state of the vessel (Fig. 10) demonstrates the condition as received. Within days, supplies were gathered in order to affect repairs on the boat. The original rub rail was removed, as dry rot had rendered it useless. The hull was then powerwashed, to remove the set-in grit and grime that had sunken deep into the outer gelcoat. The hull cleaned up quickly, and the difference was quite noticeable (Fig. 11). After drying, the vessel was flipped upside-down and fiberglass repairs were affected to the rotted areas. Epoxy resin was applied to the bottom of the vessel, (Fig. 12) sealing the area entirely. Once dry, the process was repeated on the oarlocks which had been earlier replaced, to better seal them against the elements (Fig. 13). Another oarlock, on the port side, was filled in with marine-grade sealant (Fig. 14), in order to match the final oarlock, still in ideal condition (Fig. 15). At the same time, a large cut of maple wood was stained and sealed, in preparation for addition as a bench seat, while a smaller piece was prepared to serve as the new motor mount. At this stage, a great deal of work had been done to the vessel, and attention was turned to design of the adjustable oarlock itself.
Adjustable Oarlock Design- Design Problems
The design for the actual mechanism which would adjust the oarlock has several key design problems which must be addressed for construction can commence. The ideal design would incorporate elements which would allow for complete, detailed control over the adjustment of oarlock position. However, this presents a problem, as detailed control requires precision which may not be possible to create with the tools provided in the Systems Engineering workshop. . Full control can be attempted with the adaptation of existing materials, used for other purposes. An example of this adaptation uses sailboat T-rails, which are currently used to provide mobile points for the movement of sails (Fig. 16). It is possible that these devices can be retrofitted to hold a set of oarlocks, enabling them to be adjusted to any conceivable position cut into the T-rail. A suitable alternative to complete control over adjustments may be to provide a wide range of pre-determined positions for the oarlocks to fasten into, but stop short of allowing full adjustment. This compromise allows for the device to fulfill its design requirements and remain relatively easy to produce. A system which uses holes tapped through sturdy angle iron may be the easiest example of such a device, although other possibilities exist. A series of metal tubes, each one carefully soldered into place on a set of angle iron, would prove more stable, and require minimal effort to design and create.
Another design issue the production of such a device remains the composition of its component parts. Original design specs suggested that the device should use a hard wood, for it is commonly available and relatively cheap. After suitable appraisal of this design, it has become clear that wood alone will not be strong enough to withstand the rigors of repeated use. In the event of failure, a wooden mechanism would simply splinter apart, leaving little hope for repair, if any. Standard, non-adjustable oarlocks have to contend with a great deal of friction wear, which could render a wooden design useless in a short period of time. A mechanism that relies upon metal seems to make a great deal of sense, considering the associated wear and tear of the marine environment. If large quantities of metal are not available, it is possible to design a product that does use wood, reinforced by metal inserts in order to prevent the accelerated wear that is associated with the use of wood.
The final major design problem rests with the use of tools for adjustment. It is difficult to adjust nuts, bolts and screws to their tightest position without the use of tools. The universal mounting design calls for the use of a suitable bolt and nut assembly, with the nut tightened to lock the adjustable oarlock block in place. In order to assure that this nut is securely fastened at all times, it is imperative that it not be loose. It is difficult to tighten a nut without a small wrench of correct size, but these tools are easily lost on boats, either overboard, or lost to the harsh marine environment. This hardware problem can be solved in many ways, for little or not appreciable cost. The addition of a washer and wing-nut can mean that the nut can be adjusted tightly without the use of tools, and the washer ensures that even pressure will hold the entire assembly in place. If this design is not viable, a small wrench could be incorporated into the design, with the addition of a lanyard. This lanyard would secure the wrench to the assembly, preventing its loss overboard, and ensuring that the assembly can be removed at any time the user wishes.
