On this page we will pass along information on boat and marine related topics. We hope modelers will find the content useful in their projects or be inspired to start new projects based on these subjects.
Types of Tugboats
On the RC Groups Boats Dock Talk forum a question was raised about the definition of a tractor tug vs. a rotor tug vs. a regular harbor tug. I'm ( the website administrator) also a member of the Tugboat Enthusiasts Society. I passed along the question to Hugh Ware who is a writer on tugboat technology and TES President / TugBitts editor. He is currently writing a article for Pacific Maritime on developments in tugboat technology. He was kind enough to provide his expertise to address the above question. The information provided was a bit large for a single post on the forum so I am putting a link here for the file. Our thanks to Hugh Ware for generously sharing his expertise.
Tugboats 101 pdf file format
Propelling a vessel through the water has evolved over time from paddling with hands to advanced pod mounted azmuthing electric units. From the time of ancient Greece ships were equipped with dual propulsion in the form of sails and banks of oarsmen. Roman warships utilized one, two, or three banks of slave rowers. As more efficient sails were invented having large rowing crews aboard fell into disfavor. Also the advent of the ship cannon, and its need of the space rowers used, hastened the abandonment of oars. Spain and the Vikings were notable exceptions who maintained dual propulsion ships much longer. Rowers did last in a small way until the next technicological revolution, steam power.
Near the end of the 18th century the usefulness of live steam was being realized. In 1807 Robert Fulton brought steam navigation to America with his steamboat North River Steamboat, aka Clermont . The enterprise was a success leading Fulton and his partner Robert Livingston to build two additional boats. These boats were side-wheel paddle steamers.
In the third century BC the mathematician Archimedes was commissioned to build a ship (read royal yacht) for King Hieron II. The vessel was of such proportions that a way of pumping the bilges was needed. Archimedes made his now famous screw as a bilge pump. The design was adapted for moving water for irrigation by the Greeks and Romans.
About the same time as Fulton was making history with his paddle steamer a Bohemian forester and inventor named Josef Ressel was designing and testing screw propellers based on the work of Archimedes. In 1827 he received a patent. His screw propeller was a long screw device like the Archimedes Screw. In 1835 Francis Pettit Smith was testing a Ressel screw propeller when it broke off. The remaining piece resembled modern propellers and the test boat was faster than with the full Ressel unit. While Smith was working on his propeller two other men were also attempting to make propellers more efficient. John Ericsson and Frederic Sauvage both applied for patents on designs that were similar to but less efficient than Smith's. All three men claim to be the father of the marine propeller. Adoption was somewhat slow as paddlewheels were a simpler design which was easier to understand by the general public. Trusting your life to a steam engine and a magical propeller you couldn't even see was a major leap of faith. Many ships still carried masts for sails well into the last half of the 19th century "just in case".
Boat and ship propulsion is now almost entirely by screw propeller. Variations on the theme include variable pitch propellers (where the angle of the blades can be adjusted or reversed) and pod mounted azmuthing propulsors which do away with the need for rudders.
Another propulsion system is the cycloidal drive system also know as the Voith Schneider Propeller. This unit has vertically mounted foils which rotate in unison. The angle of attack of the foils is changed to vary thrust and direction.
See these Wikipedia articles for more detailed information:
Commercial fishing has been a mainstay industry on the lakes since Europeans settled the area. Before this the local tribes harvested fish and wild rice from the lakes as staples in their diets. They developed variation of their canoes that were suited to rice harvesting or fishing.
The early commercial boats were rowed or sailed. Mackinaw boats were the vessel of choice. Light, strong, and versatile they were the pickup truck of the times. http://en.wikipedia.org/wiki/Mackinaw_boat . Three methods of commercial fishing evolved on the lakes. Boats were tailored to meet the needs of each.
One of the project boats our club is involved with is the Great Lakes Fish Tug. These boats are "gill netters". On Lake Michigan and Lake Superior the fish tug evolved from open boats to a fully enclosed tugboat style hull with gasoline or diesel propulsion. A long net is set and left to collect fish. Having an enclosed boat is important in gill netting because the fish will die in short order so it is necessary to tend the nets in all weather.
Species sought by the fishermen are Whitefish, Chub, Lake Perch (AKA Yellow Perch). Due to declining stocks commercial fishing of Yellow Perch has been curtailed for the last several years. White Perch, a non-native species has been impacting the Yellow Perch populations in addition to over harvesting.
The nets are set from the rear of the boat and retrieved through the side by use of a net lifter.
The net is hoisted aboard the boat and the fish are removed by hand. The fish are iced in totes and delivered to market.
Nets are dried and repaired on racks. Missing or damaged floats or weights are replaced. You can see nets drying on racks behind the D&S.
The Great Lakes Fish Tug evolved from fishermen on the Lakes buying or chartering tugboats to set and retrieve their gill nets. Local Indian tribes in the Great Lakes fished from shore or canoes using spears or nets. When the Europeans arrived they set nets from canoes, but more often boats more familiar to them such as bateau. Later the Mackinaw Boat was employed. They were open boats and made fishing in winter or bad weather difficult or impossible. With the advent of steam power it was possible to fish farther out and in worse conditions than before. Using a tugboat still meant working in the elements so ingenious fishermen began to adapt the tugboats to their new job.
What evolved was a boat of about 30 feet to 60 or more feet in length with a mostly or completely enclosed hull. The wheelhouse was either located amidships or aft as the owner saw fit. There were also boats with two raised houses. Gill nets sometimes a mile long were set from the rear doors. The nets would be retrieved through a side door set forward in the hull. A net lifter engaged the floats and line running along the top of the net and pulled it into the boat. As the net was retrieved the fish were removed and placed in bins. The net would be folded into a bin. The catch would be prepared for market on the trip home. They would be sold to a wholesaler or processor at dockside. Some fishermen also operated processing and sales operations. The Smith family in Port Washington, WI operated a boat, smokehouse, fish market, and restaurant in downtown Port Washington for many years.
The durability and stability of these vessels has earned them respect. Some have found second incarnations as dive boats for commercial diving companies and SCUBA shop excursions.
Inside a fish tug.
We are fortunate to have some examples of fish tugs on display and open to visitors at our local maritime museums. Her are some photos from those boats:
On display at Door County Maritime Museum's Gills Rock facility. Door County Maritime Museum
Looking Aft Kahlenberg Diesel Power Amidships
Forward Net Lifter Hope Model
On display at the Rogers Street Fishing Museum Two Rivers, WI. Rogers Street Fishing Village
The Buddy O Net Lifter (the style is a little different than on the Hope)
Fish tug gallery
Commercial fishing can be a dangerous occupation. Most people have heard of the Andrea Gail and the Perfect Storm on the Atlantic Ocean, and seen Deadliest Catch on TV. Accidents and losses are not confined to the oceans. On December 11, 1998 The fishing vessel Linda E was on her way to Port Washington WI to offload a catch at Smith Brothers Food Service. Here is the story of her final trip published in Milwaukee Magazine November 1, 2000.
Links to more information on fish tugs:
The fishing apparatus below uses containment rather than snagging to catch the fish. With a gill net the catch must be retrieved daily as the fish die in the net. With trap netting the catch is less perishable and the boats used can be less substantial. A wait for good weather to tend the nets won't cost a lost catch. The photos below were taken at the West Shore Fishing Museum outside Menominee MI.
Trap Net Boat
A trap net is a box made of netting held on the bottom by floats and weights. It has a tunnel that the fish swim into and become trapped in the box. The net is lifted to the boat and the fish are emptied into a hold. A large open deck is required for working the traps. Another type of trap is the Fyke net. It is a long net tube which the fish swim into.
Pond (or pound) Net Boat
The pond net is a square containment with nets supported by poles driven into the lake bottom. The top is above the water surface. Smaller open boats are favored for working near or inside the nets.