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Old Jul 14, 2014, 05:58 PM
mmerry2 on Youtube
mike_m2's Avatar
United States, MD
Joined Nov 2010
86 Posts
Build Log
RTR Conversion of R/C Seaport Tugboat

I bought my son an RC tug boat so he would have something to run in the water when Iím flying my RC float plane. I bought it knowing that the electronics would probably need to be replaced. Iím going to tell you about the boat and talk about the upgrades I did.

RC Seaport Tugboat Upgrades Plus FARM Float Fly BONUS! (10 min 57 sec)

Here is some background information about the boat. Its 20Ē long, 15Ē high without the flag and 8Ē wide. You can buy the tugboat from HobbyKing for about USD$50, plus S/H, but I bought mine off of Ebay. It comes already assembled. It includes the boat, a display stand, a transmitter, a NiCad battery and a charger.

The tugboat is nicely detailed. Itís got a red tower with a sprayer on the top that rotates manually. There is a crane on the side, a wench on the front and back, rubber tires around the hull and even a life raft. The cab has windows you can look inside. While the electronics arenít great, the construction of the boat is pretty good, with pieces that screw together to make modifications easy to make. It has waterproof switch on the back of the cab to turn power on and off. LEDs on the top of the cab indicate when itís powered on.

The tugboat turns left and right. It moves forwards and backwards, but the throttle is only completely on or off, nothing in between. It also has an interesting pump system. The bottom of hull has holes in it that let water come into a reservoir . The pump pulls the water from the reservoir and pushes it up a tube to the sprayer on the top.

Upgraded Parts
Letís talk about the new stuff I put in the boat. Iím going to put links in the video notes for all stuff I used.
1. Radio System:
Stock: The stock transmitter uses a 9V battery and has a very cheap plastic feel to it. It runs on a 27MHz frequency with limited range and a chance of frequency conflicts. The receiver and controls for throttle control, pump and steering are integrated into a single circuit board. The antenna is routed through this plastic tube that doubles as a flag pole.
Upgrade: I yanked out this entire circuit board and replaced the radio system with a 2.4GHz 3-Channel system. The transmitter includes a Li-Ion battery. This system gives me a very long range and frequency hopping so I can avoid conflicts. This transmitter has a bunch of other nice features.

2. Motor Speed Controller:
Upgrade: I installed a 25A brushless car speed controller. It needs to be a brushless to handle a brushless motor. It also had to have a reverse function so that I could put the boat in reverse. This ESC is small, but powerful.
3. Motor:
Stock: The stock motor is a brushed DC motor. Itís not efficient and it doesnít have much power. Brushless is the way to go.
Upgrade: I replaced it with an extra brushless motor I had available from an RC plane.
4. Pump Speed Controller:
Upgrade: I installed a 20 Amp brushed speed control to control the pump.
5. Pump Motor:
Stock: The stock motor is a brushed DC motor. It pumps out water in small intervals and reaches about 10 feet. Ours only lasted a few runs before it stopped working.
Upgrade: I found a new pump on Ebay that works great. It has a wide power input range, so it runs on the 2s LiPo fine. It produces a stream that reaches about twice the stock pump and runs in a continuous stream.

6. Battery:
Stock: The stock battery is a 1,000mah 9.6V NiCad pack.
Upgrade: I replaced it with a 6,000mAh 2-cell Lithium Polymer pack. While the voltage is lower than the NiCad, we are able to run the tug boat for over an hour. I also added a Y-connector to send power to the 2 speed controllers. I could have gone with a different capacity pack, but this was one I took out of my RC truck. I wouldnít go heavier though because it starts to get too top heavy. I use a little LiPo alarm on the pack to tell me when voltage gets too low.
7. Universal Coupling Joint:
Stock: The stock coupler between the motor and shaft is plastic. Mine got stripped after running with the new motor.
Upgrade: I replaced it with a universal coupler made of steel.
8. Steering Mechanism:
Stock: The stock steering mechanism uses a small geared motor to move the rudder. It has limited movement and turns one way better than the other. It does have a trim you can set, but itís hard to use.
Upgrade: I replaced it with a standard servo to increase movement and get better response. I had an extra one lying around from an RC plane. I can use the transmitter to adjust the servo trim if needed. I installed a new control arm with clevises.
Other Materials
Here are some other materials I used to complete the upgrade:
1. Fuel tubing: Some new tubing for the pump.
2. Deans T-Plug battery connectors: Some new Deans battery connectors.
3. Servo Connector: I put a servo connector on the stock LED wires and just plugged it into the new receiver.
4. Amazing Goop & Three 2-ounce fishing weights: I used Amazing Goop to glue in three 2-ounce fishing weights in the hull bottom to help stabilize the boat. Without them, the boat tips side-to-side very easily.
5. Marine Grease: I read itís a good idea to use a special water-resistant marine grease to grease the boat shaft periodically. Some grease the shaft before every run.
6. Lego Figures: My son wanted to embellish it with some Lego figures, so we added a captain and sailor that were held together with CA.

Closer Look
Letís look inside the boat to see how the upgrades were done. Here are the steps to get it apart:
1. Take off the battery hatch, by removing one screw and turning these two red locks to the outside. I decided not to replace the screw when putting it back together.
2. Take off the 2 screws above the life boat and remove the life boat. I put Velcro on the bottom of the lifeboat so I wouldnít have to remove screws each time.
3. The green deck removes from the red hull by unscrewing 10 screws around the top of the deck.
4. Remove the 2 screws on these two red smoke stacks and stacks come off.
5. Remove the white cab from the green deck by removing 4 screws from the perimeter of the deck

Once inside, I removed the stock battery tray, pump, motor, steering mechanism and speed controller/receiver. I added some Velcro to the top of the reservoir to attach the new battery to.

I added weights in three positions along the hull bottom.

To remove the pump, you just remove these 2 screws and it slides outs. I made this by taking some square dowels, cutting holes in them and sliding them over the posts. I glued a piece of sheet metal on top of each dowel. I then glued a piece of plywood between them and screwed the pump to the plywood. It makes it a lot easier to work on the pump.

The motor is attached in the similar manor. The motor also has a universal coupling joint. I had to enlarge its holes a little to get it to fit the drive shaft and motor shaft. Make sure to put some thread lock on its grub screws, because mine did come out. I also used some Amazing Goop in its pin to keep it in place. I dremelled a flat spot on the drive shaft to give the grub screw something to rest on. I added a wheel collar on the drive shaft to help keep the shaft in place. Itís important to leave a small gap after the collar.

Where the old steering mechanism was, I fit a standard servo right on top of the existing posts. I just had to reinforce them with some Amazing Goop. I cut the steering disc in order to attach a clevis to it. I ran a control arm to the servo.

If we look inside the cab, you can see where I attached the motor speed controller, pump speed controller and receiver with Velcro. I wired the stock switch in place of the motor speed controller switch so I can still turn the main power on and off. Since there are 2 speed controllers that both have BECs plugged into the receiver, you have to remove one of the red wires from the servo wire so you donít have extra power on the receiver.

On the receiver, here are the connections:
Channel 1: steering
Channel 2: throttle (forward and reverse)
Channel 3: pump
VCC: used to power LEDs
I connected the LED power wires right into the receiver. The receiver has 5 volts power coming from the ESC. Normally, 5 volts would be too much power for an LED, but in the stock setup they are wired in series with a resistor, so I only had to put a male servo terminal on the wire and plugged it into the receiver.

The receiverís antenna slides nicely up the existing antenna tube in the cab.

Overall, I am really happy with the upgrades. It was fun making them. This tugboat has a lot of potential and my son loves his new and improved tugboat. So what do you think? Do you have a tugboat? What were some of the upgrades that youíve done? What do you like and donít like about the tugboat?
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Old Jul 14, 2014, 11:07 PM
Sometimes I am the weapon
Harquebus's Avatar
South Korea, Gyeonggi-do, Ansan-si
Joined Jan 2006
1,064 Posts
Good conversion techniques and info. There's a lot I did not know about the boat.

What, no paint? Something has to be done to tone down the shiny plastic and give it a proper scheme. Heng Long/Dickie had to mold each piece of plastic in a different and cheesy colour--and the result: no cohesion. "SUPER WORK BOAT" has to go too, don't you think?

An idea: painting it could be left up to your son as I did not read here that he had a hand in the conversion process. Just a thought, FWIW, YMMV, FYI.

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Last edited by Harquebus; Jul 14, 2014 at 11:12 PM.
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Old Jul 14, 2014, 11:28 PM
Registered User
Monterey Bay California
Joined Feb 2004
14,152 Posts
Nice conversion, Mike!

Harquebus' picture illustrates how effective a bit of paint and detailing can be-
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Old Jul 15, 2014, 08:22 AM
Boaters are nice people.
Sneek, Netherlands.
Joined May 2004
5,088 Posts
In addidion, take a look at the conversions and paintjobs on the Mayhem forum:

Regards, Jan.
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Old Jul 15, 2014, 01:46 PM
Truly Addicted to RC Boats
cartix's Avatar
USA, NY, New York
Joined Oct 2005
132 Posts
Nice conversion and great video description. I did a similar job on mine. It is a great platform for customizing at a good price. I used spare electronics for my RC cars.

My setup:
Stock motor with Novak XRS Frd/Rev ESC.
HiTech 5945 Servo (yeah it's overkill)
Spektrum DX5e Tx
No water pump.
Repainted some parts in satin blue with black rails, still have to repaint the tower. Tower has been shortened at the base and I also added 2lbs ballast (modeling putty), she sits just right in the water and doesn't roll as much. A work in progress...

Runs sweet!

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Last edited by cartix; Jul 15, 2014 at 01:58 PM.
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Old Nov 03, 2014, 03:44 AM
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Joined Apr 2014
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I converted my Seaport with a futaba system and esc from aquacraft boat. stock battery and motor. ripped out all stock workings and installed a futaba servo.f
plugged the ballast tank and filled with lead weights

I also decided to weather it a little so it didn't look so rtr. I streaked the superstructure and hull with Tamiya weathering rust color, then hit it with clear dull coat to take off the shine.
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Old Nov 03, 2014, 03:48 AM
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double post
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Old Nov 04, 2014, 12:11 AM
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Joined Jun 2012
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Really enjoyed the video, thanks for posting. Someday when I have more time I'd like to try upgrading and customizing one of these.
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Old Nov 06, 2014, 10:02 AM
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Houston, TX
Joined Jan 2008
5,779 Posts
Thanks for the post. My son likes boats and I got him a speed boat but he seems to be more interested in scaled boats. This is the only economical tug that I can find. Reviews on other sites say that the boat top and bottom are molded in one piece and can't be taken apart to customized the electronics. I'm glad you set the record straight.

I've got plenty of motors and ESCs from planes and helis so won't take much to customize to brushless. I'll probably do away with the water tower if that stock motor ever breaks.

There will be a SeaPort under the Xmas tree this year!!
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