Pacific North West log tug

Chum444 Mensagem de abertura há 18 dias 54

Log tugs had very little freeboard since the deck crew often needed to jump from the tug’s deck to the log boom & back.Doesn’t sound like fun to me!

The first deviation from the 1:1. A steerable Kort nozzle & a cage to prevent floating loose logs from damaging the Kort &/ or the prop.

Preformed components for bulwarks & shear clamps.

380 size brushed motor with gear reducer.

I’ve had this hull for a few years & am now getting to building a model of Harken Towing’s tug HARKEN No 1. As per my usual it will not be an exact replica of the real boat. Sometimes a scale model has to accommodate needs not found in the 1:1.
So, here we go. This class of tug boat was the workhorse of the log boom (essentially a floating group of numerous logs) towing industry in the Pacific north west. Towing these log arrays on the PNW rivers, notably the Fraser, was the most economical method of getting timber from the forests to the sawmills. I don’t know if the log towing industry still exists as a going business, but I have doubts since many of the log tugs have been repurposed. Anyone herein who has historical knowledge of the industry &/or its current status please share any information.

Gostado por DWBrinkman and RNinMunich and

Chum444 #2 of 3 há 10 dias 15

Progress

Into the ballast tank. With the battery located a bit forward of amid ship it will take a bit over 2 lbs or 1 kg to get to the intended waterline.

With tugs & workboats I prefer to paint the hull early on. Then the scrapes, dents, bangs, etc that occur during the building process add realistic weathering to the finished build.

I’ve been working on the hull recently. Finalized the location of the motor & gear reducer & installed the mounting foundations. For me this is always a milestone event allowing hull work to move ahead.

Gostado por Fishercat and chugalone100 and

3 comentários

AlessandroSPQR
Almirante da Frotahá 8 dias
@Chum444
Hi Bill
Thank you for the precise and comprehensive explanations.
I understand your point of view and your choices.
I don’t think you’ll have any issues with the motor, even though its diameter is smaller than that of the propeller, because you have a mechanical gear reduction in place anyway.
You can always change your mind later; 30–45 minutes isn’t bad, but twice that would be better—and if you don’t want to spend time on a switching circuit, you could always just set up a parallel connection.
Gosto1
Gostado por Chum444
Chum444 Silver
Contra-almirantehá 8 dias
Hello Alessandro. Thank you for your comments. I’ll offer an explanation. This is a small tug; just over 16” or 40.6 cm. The motor is coupled to a 3:1 gear reducer so the current draw should be fairly low. The 4 blade prop is 45 mm paired with the Kort nozzle. I don’t know the pitch but visually it is low to at most very moderately pitched. However, it is the wild card in the performance characteristics. The prop violates the “ diameter not larger than than motor’s can” rule since the motor is 380 size. So fingers crossed. I’m hoping the slow scale speed of this tug will compensate for the diameter & pitch of the prop.
Due to the precise alignment required for prop clearance in the Kort the shaft angle within the hull is minimal. A 540 side motor would have to be direct drive since shaft height/angle would prevent use of a gear reducer.
I manage to get around 30- 45 minute run time from my other boats powered by a single 7.4v, 3000mah NIMH battery. None of my builds are fast hulls. Scale speeds typically 12- 15 Kts. All but one of them are single screw boats; that one is tug with twin screws in fixed Korts. The only other exception is my 47 ft Buddy Davis sport fisherman. It has twin 3 blade high pitch props powered by two direct drive 540 size motors. For that one I did run two 3000mah NIMH batteries in parallel configuration. Since I never run at wide open throttle for extended periods I still enjoyed a 30-45 minute run time.
So, we will see. I may need to return & seek your switching wiring diagram.

Bill
Gosto2
Gostado por Fishercat and AlessandroSPQR

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Chum444 #3 of 3 há 4 horas 2

Structural work

Bulwark installation. Shims are to create constant width between hull side & bulwark. Gap is closed by a covering board.

Beginning to construct the sheer clamp. Aft deck will be mated to bulwark 1/16” above the bottom edge.Also included, a note to self.

One of my favorite parts of a build,; the structural system to support the deck. As usual, I have no plans for construction. Size of components & location derived from proportional measurements from photos. I was generously provided with house & trunk cabin measurements taken from the real tug by another builder. There is also a lot of TLAR that enters the equation. (And plain guesswork).
The first real challenge has been the stepped foredeck. Many logging industry tugs, particularly those involved with towing log booms, have VERY little freeboard since the deckhand has to leap back & forth between the tug & the towed log boom. So creating a low freeboard stepped deck has me thinking.

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Pacific North West log tug