Inland River Pushboat
A currently on-going project is the design of an inland river pushboat to mate with a dedicated barge for a car-ferry service. The pushboat is 60’ LOA x 18’ beam, with a pair of 300 BHP diesel engines, driving 45” diameter Kaplan style propellers in Kort nozzles. The boat has two steering rudders and four flanking rudders, as is commonly found in inland waterway pushboats, where a high degree of maneuverability is needed. That is certainly the case for this application in which constant maneuvering and reversing is called for in the river ferry operation.
This graph shows the performance of the pushboat, for the selected combination of engines, reduction gears, and propellers. In this case the chart shows that, at the maximum crossing speed of the ferry (10.6 MPH), each propeller will absorb about 270 SHP at 2200 engine RPM’s.
This picture shows the placement of the Kort nozzles in the shallow tunnels of the afterbody. The hull-form is quite simple, for ease of construction, but features very gentle buttock shapes, for low resistance and smooth inflow to the nozzles.
R/V WECOMA crane support “crutch”
When Oregon State University replaced the aft crane on their research vessel WECOMA, they needed a new support structure to hold the crane in place for over-side towing and picking operations.
The picture and drawing show a tripod structure which Alan designed. The feet of the tripod bolt into deck sockets spaced throughout the working deck. The portable nature of the tripod gives the capability to locate it in several different places around the periphery of the aft working deck, to suit different over-side crane operations. Or the tripod can be removed and stowed ashore for missions that do not need a strong over-side boom support.
Similar to ISO containers, these accommodation modules are designed to be carried on the deck of a ship for one or more voyages, then readily offloaded for assignment aboard a different vessel. The modules augment the regular accommodations of a ship. These modules are designed to be stacked two-high, so that any given module could be carried on the first tier or the second tier. The design incorporates standard ISO corner fittings. The drawing below shows a layout for an office/laboratory, typically carried for a specific cruise aboard an oceanographic vessel. Other uses are found in the offshore industries (petroleum and wind). Other modules are configured as living spaces for the industrial personnel (or researchers) who are not part of the ship’s crew. One design is laid out for berthing of six people in three staterooms. Each stateroom includes a toilet/shower module. Another module configuration is for lounge and exercising. With the module concept, the mother ship gains flexibility for different assignments.
47’ Motoryacht Concept Design
The purpose of concept design is to demonstrate the feasibility of an idea, to enable a rough estimate of the construction and operating cost, and to give the prospective owner a chance to consider the pros and cons. The conceptual design is also used as a base from which discussions and other design variations can be explored and compared, leading to a more refined preliminary design, and eventually to a much more detailed contract design.
The concept design (drawing one and drawing two) was prepared for a local family seeking to upgrade from a well-liked, but cramped, boat, to a slightly bigger boat with the possibility for week-long cruising and even a live-aboard lifestyle in later years. The owner had specific requirements for the arrangement of spaces, which were not to be found in production boats. The fiberglass hull utilizes an existing mold which has been used by Sunnfjord Boats (Tacoma, WA) for a number of motoryachts in the past. The principal characteristics are as follow:
Length, overall 47’- 6” (14.48m)
Length of waterline 42’- 6” (12.95m)
Beam 13’- 4” (4.06m)
full load displacement 54,000 lbs (24.5t)
installed horsepower 242 BHP
cruising speed approx 10 knots
Motoryacht ARIES Repower
The fiberglass motoryacht ARIES was constructed in 1978 by Little Hoquiam Boat Shop (hull) and Vic Franck’s Boat Company (outfit and interior). The present owner was willing to invest an amount equal to full value of the boat in modifications to gain better performance - through repowering, a stern extension, and trim tab replacement. Prior to selecting the reduction gears and designing the new engine mounts, Alan carried out a hydrodynamic analysis of the planing boat.
A small part of the analysis is shown. The effect of trim tabs and load condition is shown over the speed range of 20 to 26 knots. The project resulted in a modest reduction in the planing trim angle and increase in the top speed. The new engines are Cummins Model QSC8.3, with ZF Model 304-A reduction gears.