My radio controlled tugboat

[Beez 5,091]

With the Tug finally added to GTAO it seems like now is the perfect time to share this with everyone.

I documented this on an R/C forum years ago so I'm just going to copy it here. 

Well, here goes. This will be an after-the-fact build log of the Pono harbor tug from Harbor Models. I built this in 2001 and took a few photos along the way, it is still not done. I collected a lot of information on the real Pono and will include that for future modelers who would like to build this kit.

The real Pono is in the Port of Honolulu, Hawaii and is operated by Sause Bros. Inc.. Man, that's gotta be a tough gig, working on a Tug in Hawaii. Below are some of her specs.
 

M/V PONO O.N. 995 739
2,400 HP TWIN SCREW TUG
WITH 37A KORT NOZZLES & QUAD RUDDERS
The vessel is a welded steel, single chine, twin screw tug boat of welded steel construction, designed by Sause Bros. Ocean Towing Co. Built in 1993 by Fashion Blacksmith of Crescent City, CA.

PRINCIPAL CHARACTERISTICS
Length (reg) - 75'-0" Net Tons - 100
Length (oa) - 80'-0" Gross Tons - 147.8
Depth (mld) - 13'-0" Fuel Oil Capacity - 22,500 gal.
Breadth (mld) - 28'-9" F.W. Capacity - 1,100 gal.
Draft (max) - 10'-5" Bollard Pull (Ahead) - 66,000 lbs.
Disp. (Max) - 265 L.T. Bollard Pull (Astern) - 48,000 lbs.

MACHINERY
Main Engine - (2) Cat model 3512 rated 1200 hp at 1800 rpm
Rev/Red Gear - Reintjes model WAF 660; ratio 5.95:1
Prop Shaft - 7" dia S.S. with water lube bearings
Propeller - 4 blade 80" x 70" in 37A nozzles r/l outboard (4) rudders

DECK MACHINERY
Tow Winch - Intercon single drum model SD-175 w/gypsy
Line Pull - 45,000 lbs @ 50 fpm
Power - Hydraulic 90 gpm from aux. engines
Bow Winch - McElroy model 528-1 drum; 2 gypsies
 

I wrote to Sause Bros. and they sent me copies of the real plans, the data sheet and some photos. Then in the spring of 2001 Beezwife and I took a vacation to the Big Island of Hawaii so I contacted Sause Bros. again to see about taking a tour of the tug. They were very nice about helping me out and we set up a time to meet. I added a couple days in Honolulu to see the U.S.S. Arizona and U.S.S. Missouri and to visit the Pono. They gave me the whole tour and I took a ton of photos. You can see them here.

https://beez.smugmug.com/Boats/Pono-Tugboat-Hawaii/

The Harbor Models Pono is 1/24 scale, 40” long, 14” wide and weighs in at 50 lbs. It is a semi-kit and consists of the hull, cabin, wheelhouse and exhaust stacks in fiberglass, plywood deck, some cast resin fittings and set of full-sized plans. It’s a twin screw tug and can be built with open props and dual rudders or Kort nozzle props with quad rudders (just like the prototype). Either setup can be ordered from Harbor Models and it will include props, rudders, Kort nozzles, shafts, stuffing tubes, universal joints, Pittman 3700 motors and motor mounts. I opted for the kort nozzle setup.

 

 

Since this is my first RC boat I wanted to get it on the water as soon as possible. I figured out the minimum I needed to get it on the water and devised a way so that the superstructure could be taken apart to add details later.
 

 
The hatch is for access to the rudder servo which is a heavy duty 1/4 scale servo.

 

Wood blocks were epoxied in the hull and the kort nozzles were screwed to them.
 

The rudders initially tipped inward as seen here but after more cutting and filling I got them vertical.

[Beez 5,091]

Another shot of the running gear.


In this photo you can see the machinery deck I built. There is room inside this hull for a small child.

The ends of the prop shafts held in place with a solid chunk of 3/4" plywood bonded to the hull. Belt drive pulleys on the ends. Stainless steel screws were bonded to the underside of the machinery deck to create studs for the motor mounts. The strap is to hold the batteries.

 

This is the "Steering Solution" that Harbor Models sells and comes in the kit. Instead of control arms to move the rudders there is a thin metal cable that goes from one side of the servo control arm around a pulley on each rudder and then back to the other servo control arm. Each pulley has a set screw to lock it to the rudder shaft and two holes to run the cable through so it won't slip

I could not figure out how the rudders would stay in place and thought they might ride up and out of the bottoms of the kort nozzle shoes. So I made hold-downs out of rectangular brass tube and nuts and bolts. The underside of the brass tube has a hole in it for the top of the rudder shaft. These have worked fine but I wonder if they are necessary.

You can also see the wood blocks for bonding the kort nozzles and some small blocks to attach the rear deck.

Like I mentioned in the last post, the decks were painted different colors over the years and you know, vessels are bought and sold, so I decided to paint it whatever colors I wanted to. I really do not like the brown color Sause Bros. use so I pretend that they sold the Pono to Beez Towing and I repainted it in the Beez Towing colors.  It's ok to pretend, we're playing with model boats here.  

At this point it is operational but it lacks a lot of detail and fittings.
 

Windows are cut out but there's no glass in them. The bitts (or bollards) are made of brass tube. I bonded a machine screw into the bottom of each horizontal tube with JB Weld and they are bolted through the deck with a nut underneath. Filled the ends of the tubed with bondo and sanded them flush. All four bitts are very strong and can be used to tie to my barge.
 

 

The scuppers in the plans are wrong and would weaken the bullwarks so I went off the photos for them.


I think I got this door too high. 

[Beez 5,091]

Here is a good trick, buy the winches for the Tito Neri. Tito is 1/33 scale and Pono is 1/24. I cant remember where I got the plan views of these winches but they are exactly the same size and damn near the same type as those on the Pono. The bow winch is almost exact and the towing winch is the same basic type with minor differences.

I left the portholes in the lower superstructure open for ventilation.

[Beez 5,091]

Again, this is an old photo so excuse the messy wiring. I wanted to leave all the wires long in case I had to move stuff around. I still have not shortened any of it but I zip-tyed some of it to make it less messy. It has all worked fine for a few years now so I guess I should shorten them up.  

 
HUGE space in this hull. I made a little electronics shelf that is held in place with the spring clamps. Below it are inline spade-type fuse holders with 25 amp fuses for the motors. Each motor is switched with the big toggles. Speed controllers are Electronize FR30HX. Rx is HiTec. There are three 12v gel batteries in there.

 
Motors are Pittman 3700s with home made belt drives.
 

Bought the pullies and belts from SDP-SI. I elongated the holes in the motor mounts so they are slots so I can tension the belts. Nuts are nylock.


Motors surpressed!

[Beez 5,091]

I knew I wanted to tow with this tug and the copy on Harbor Models site about the Pono says you can tow a person in a rowboat. That sounded COOL! Nevermind that I still have never actually done that.  So I knew I had to make a strong tow point.
 

I cut one end of a link of chain off and made a small plate from brass, JB Welded them together.

 
Then JB Welded two brass tubes to the bottom of the hull and to the deck. The link fits into the tubes and is epoxied in place.

I wanted to get it on the water ASAP so I could have fun and add detail later. This was in 2002.

 

 

 

 

[Beez 5,091]

I constructed the superstructure so I could take it apart and put it back together with a few screws. This allowed me to play with it on the water and take it apart to finish it properly. The next set of photos show some more progress. Smoke stacks are on, wheelhouse has an interior, front bitt (or bollard?) is one, tires on the sides and bumpers on the bow.
 

For the front bumper I's seen a really nice one on someone else's boat that was made of black rubber sheet with reinforcing fiber in the middle. I looked high and low for this stuff and never could find a place to buy it. Then I thought I'd try to use a motorcycle tire. What a freakin' mess! It was a used roadracing slick and I tried to cut it so the curves of the tire would work with the curves of the hull. It was wicked hard to cut, made a mess, looked terrible and the steel belts left these sharp wires sticking out that cut me.  

Then I got some special glue for rubber and tried cutting up an inner tube into small rectangles and then glueing them together. Another big mess that was unsuccessful.

I still liked the idea of the rubber with reinforcing fiber in the middle so I went to an auto parts store and bought some thin fan belts. I made a jig to cut them into equal sized pieces and another jig to drill 2 small holes in each one. Then strung them together with safety wire. Then epoxied (or maybe used JB Weld) it to the hull. The top row is cut at an angle.

I an very happy with the way it came out and it is also very functional, just like a real bumper. It is also heavy so I was able to lose the ballast bean bag that went in the bow.

 

 
The tires are detail parts for 1:24 cars. I mounted them on a sanding drum and spun them with a drill press, held sand paper to them to sand off the tread because nobody uses brand new tires on a tug. Then mounted them with chain so the flop around. The real Pono didn't have them but I like the look of tires on a tug.

The mast was made of brass tubing and piano wire. This was really my first time doing silver solder and I remember having a hard time finding it. I still not even sure if what I got was real silver solder. I'd ask and the sales person would look at me like I had a 3rd eye and say something profound like, "I dunno?"

 

I epoxied a rare earth magnet to the bottom then put a small post extending downward from the mast support platform. It has a small piece of steel on it and the magnet attaches to it in the upright position. Separate them and the mast lowers to go under bridges. It's kind of a low tech animated feature.

Mast has functional lights on it that someday I hope will be functional.  

[BMSTANG 182]

That is awesome!

[Beez 5,091]

The wheelhouse interior is where I could really get creative. When you build from scratch you never know what can be used to simulate something in miniature and you start to look at everything differently.

I reduced the plans of the real tug, charts of Honolulu Harbor from the internet, a painting of a hula dancer and the phone list from my job at the time then glued them to thin wood to simulate a frame. Seats are from a Chevelle model kit.

This is how it currently is now. I had planned much more detail, functioning lights and lots of weathering but it's been stalled for more than 10 years now. Damn that's depressing to type. I can't even remember the last time I had it in the water. There's a guy at my work who is into R/C planes and cars and he's been urging me to get it running so maybe this summer.

 

[JustHatched 12,123]

Very cool,

 

Couple questions, your hitec transmitter, is it stick style like an aircraft transmitter or wheel type like a car (or does boats have a whole other style?) and are brushed motors the only option for this type of model or is a brushless too hot for a tug?

 

Very nice detail Beez, perhaps I should employ you for a B17 project I have blueprints for when I have time and money.

 

This could be your next boat project http://www3.towerhobbies.com/cgi-bin/wti0001p?&I=LXERCK&P=ML

 

I have been looking at a speedboat to play on the ponds at the state park next to me, can't decide between electric or nitro. Rose would probably shoot me if I did though considering the planes

[Beez 5,091]

The transmitter is stick style but the forward/ back movement is not spring loaded. Both sticks have little steps so I can move the throttles to say, half speed and they will stay there. Right stick is right motor, left stick is left motor and steering. Frequency is changed to a land channel. Both motors a re totally independent so I can steer with them or put one forward, one reverse and the tug will spin within its own length. There is even a technique where I can make it crab sideways just like a real tug.

you could use any motor but for this you want torque so you don't need a hot motor. The Pittmans I have are used in wheelchairs to but people use car window and windshield wiper motors too. You don't have to gear them down like I did but it gives more torque and better slow speed control.