dallas2254

Installed and hooked up all the electrical to drive the rudder, motor and bow thruster. Not sure if one battery will be enough wieght though. Looking at the possibility of getting a large trolling motor battery to fill the hull up. I think they make one that is over 20 inches long and 8 inches wide. Perhaps tomorrow it will be in the lake.

I ran the motor for about 10 minutes tonight.

RCBOATMANIAC

Dallas,

Your tug is really looking good, the battery looks like it could get lost inside the hull. Have you gotten your final weight set yet for your draft of the boat to get it down to the proper water line. The guy with the 51" tug and if I remember right he said his weighed in at 80 pounds, I was just curious to see how much yours weighs in at for proper drafting.

I am still trying to work out all the bugs on my bandsaw I bought, it doesn't have pitch rollers for guides on the blade all they are is pins you have to adjust to keep the blade from walking around, it at least has little rollers in the back of the blade when you are pusking the wood through, but in time I'll get all the bugs worked out and get busy on my tug. It might turn out to be a winter project, to much work to do around the house to get any time to play with the hobby, bad enough I haven't had the time to take any planes out to fly yet.

Oh well!

Good luck on the madian voyage.

dallas2254

Today was the big day for the Janet Larayne and it did wonderful. The first time I have ever launched a boat and not have some water in hull by the end of a run. I had tissue and blue paper towels around the shaft and bow thruster and not even a pin head of water. Getting up to the weight needed to put her at water line is going to be a challenge. I grabbed some of the weights from my dive belt along with the blue top optima battery and not even close. Still and inch and a half to go. But is far enough to see that the hull was very stable with the weight I was using and the bow thruster and prop were under the water line.

I had no dead weight loaded into the hull other than some excess epoxy in the keel area. The hull therefore is easy to carry. The battery and weights added 68 lbs and it could easily take that much more to put it down. More battery power = more weight, so I am going to buy a two more blue top optima’s at 39 lbs a piece and see if that helps. Seems to be enough room and those batteries and are easy to carry with their handles.

A few problems occurred during the 40 minute run. The MFA 800 motor with the 2 to 1 belt drive does get really hot pushing that 5.1 inch 5 bladed prop at any speed. Some modelers have said in other posts that there motor is staying cool. Not this puppy. I think the 5.1 inch prop is a problem for this motor. I also had one side of the shaft coupler allen screw work its way loose even on a flat spot. Too much force I guess. At least the prop did not spin off with the jam screw and lock tight on it.

SO I am rethinking whether to wrap cooling coils around the motor and put a pump on board (electrical draw and battery reserve certainly is not a problem) OR I upgrade to a bigger motor OR I figure out how to put a bigger ratio belt drive on the existing set up.

The Futaba 6AE transmitter and receiver worked great along with the bow thruster and motor controller. I only had a 6 something torque servo for the rudder control but it worked great too.

It attracted quite a bit of attention by boaters driving by...something they don't see on an 8 sq mile lake cruising around looking at homes. A couple of friends made a point to stop by to see the launch (they don't do RC) and enjoyed playing with it.

Besides the above mentioned areas of improvements I am still planning on adding a high volume fire monitor, sound system, lots of lights.

The first picture shows the hull without a battery or any weight in the hull.

grinder-RCU

My Feedback: (1)

Looks good. That sucker is going to take lots of ballast to get her down to the waterline. We need video!.

grinder-rcu

dallas2254

I Picked up a couple more [link=http://www.optimabatteries.com/optima_products/bluetop/specs.php]D34M Blue top optima [/link] D34M batteries today for a total of three blue tops. The pictures below show just two of them; the third is in my Boston Whaler......opps that work since that is my retrieval boat if I need it. Need one more optima. That is 129 lbs of battery weight for ballast and maybe enough capacity till the motor 'times out' and needs to be zero timed. (Airplane engine jargon)

Order arrived from Harbor Models Today for a [link=http://www.harbormodels.com/site08/main_pages/soundmodules.htm]new tug boat sound system[/link] and a speaker to go with it. I love the sound. I also picked up an electronic switch (controlled remotely) to use aux sounds like bell and horn on it. Take a listen to their demo. Pretty kewl sounding. I also got [link=http://www.harbormodels.com/site08/radar.html]radar and geared motor[/link] to run it. That is one small motor.

Next step is to hang some [link=http://www.horizonhobby.com/Products/Default.aspx?ProdID=TAM9400462]10:1 scale truck tires[/link] and bow bumper on it.

I need some ideas on a bigger motor that will handle the 5.1 inch prop if anyone has some idea. Would prefer a final drive rpm of around 1500 rpm while in the water. I saw were someone was using a Bosch American windshield wiper motor. Need some ideas where to find such a motor. Prefer to order new off internet or get a model number to order new. I afraid that the [link=http://www.mfacomodrills.com/gearboxes/960d_series.html]MFA 800 2:1 belt driven motor [/link] is not long for this world.

Kaymac

Dallas - Comparing the physical size of the motor to the Electronize 30 controller, I would think that you might do well with a Pittman 3700 using the same gear ratio. Shaft speed is 3700 and your ratio looks to be 2/1 so 1800 is about right. The Pittman is about the size of a small beer can and is a robust motor. PM me and I'll tell where to get one....
Keith.
www.kaymac.ca

LynxRA

I am a friend of Dallas and am building the same 85 ft Harbor Tug/Angels Gate and would be interested in getting the Pittman 3700 for my boat also. Where can they be found and what is the price? Lynx

[email protected]

nick_75au

What about a bigger gear reduction, I know a big coast guard Comanche that uses a 700 geared 11:1, turns at 2500 RPM and spins a 100 mm prop , no cooling and very low current draw, uses a 15 amp Electronize speed control. They cost about $120 Au dollars, there is an 11:1, 12:1 and 16:1 ratio , 16:1 at 24 volts spins at 1750 RPM. The company that sells these does ship to the US. If your interested Ill send you the contact details.

Nick

dallas2254

Thanks Nick

I would like to look into that option. Please send me the information you have.

Dallas

grinder-RCU

My Feedback: (1)

I was able to pick up 2 Pittman 3700 motors from Harbour models for my tug with a 33% gear reduction to a single shaft from two motors. I wil be running a 4 blade 5" prop. Hasn't been water tested yet just going by the numbers.

Grinder.

dallas2254

Well Joe,

As one of my options for repowering this big tug, I have decided to go to the other extreme and by using one Pittman 3700 motor, sans any reduction gear, via direct drive coupler to a 5.1 inch 5 bladed prop, 'ignoring the numbers', and see what happens.

I am hoping for 2000 rpm at cruise which would be 2.5 mph (a little more than scale). I have been told by 'THE ONE' that this will work. I am also throwing in a smoke generator from Harbor Models, in case there is not enough smoke coming from the Pittman motor. Lord knows there is enough smoke coming from my visa card to build this tug.

I added a Harbor Models sound system to the Tug the other night and it is the Cat's meow. In fact they have improved upon it in the past two days and I am sending it back for and update. Sounds pretty good already but I guess they want it to be really good.

BTY what is the status of the supersized 85 ft Harbor Tug #1 (your tug). #2 (mine, is functional, being used as a test bed, and in the water), #3 Lynx's is starting be be framed as we speak. You helped me out a lot on my build and I am doing the same with Lynx.

LMAO

LynxRA

I'm a long way from where you are but I thought I would send a couple of pictures if I can figure out how. Well at least I have gotten started. The frames are just tacked with CA right now as I have been making sure everything was going together without any problems. I figured just a tack here and there would let me cut things loose if I found something not the way that it should be. Slow, but having a ball now that I am started.

dallas2254

That was not that far back that I was at the point. Looks right great. Now you do the buildup of of the bumper below the bulkward using 1/4 x 1/4 balsa. You will need to soak the end pieces around the stern to make the bend without crimping the stock. I varied the lengths so that the jointing points did not over lap the pervious one by and inch or so. If I were to do it over I would have made them built it up to 3/4 of on inch vertically instead of the 1/2 inch I made them (two rows of 1/4 stock) More to scale going three high and two deep not inlcuding the first 1/4 x 1/4 stock that goes into the grove around the tug.

after you get three 1/4 strips anchored to the frames around the paremeter of the tug then you can start planking at the bulkward one row at at time moving toward the keel. I planked all the way starting at the bow to the stern. Joe is using blocks of blasa for the bow but it is easy to plank the curve to the bow with just a big hull. I never had to soak any planks. I ordered enough of of the soft wood planks to make some of the bends.

But start with the bumper below the bulkward first to set a line for the planks to follow Robert.

I am going to launch my tug tomorrow, if I have time, to see if it will take three optima blue top batterys at 45 lbs a piece to put it to the water line.

Dallas

LynxRA

Sounds great. Did you sand off the brown edges so the CA would hold better of did you use epoxy? Probably won't get anything done tomorrow with my son and daughter in-law here. All the balsa I bought, I don't know if any is soft or not. Whatever, it will all work out, just might take a little more patience. I have to get some short bristle brushes to do the epoxy. It works better than using a stick. What is the weight of your boat without batteries?

dallas2254

Yes i sanded of most of the brown edges but it really dose not make much of a difference. What helped the most is to bevel the edges of the frames to the angle that the planks come in contact with the frames especially with the three bow frames. I used medium CA glue for all of the attachements. In some places I used the thin ca glue for hardening up the wood if it was too flexible. I also spot glued each plank along the edges as I went around the hull to reduce the chance that the planks did not align with each other and create low or high spots on the hull. Since the planks are 1/8 thick you dont have alot of sanding room. I did not have to use any bondo on this hull at all. Came out really smooth. My fingers came out really glued though.

The planks in the hull area going back about 10 inches will have to be someone lapped to each others long side so sanding will be required to get that smooth. I sanded a long bevel to eahc bow attachement to get a smooth bow.

You really do not need to make much of any bend for the wood except for curving the planks sideways (bending them against the 3/8 side inch side as you make your way back to the stern and keel. I would definately try to do the entire hull in plank including the bow which is far easier than it looks. Also on your first plank at the bumper, always starting at the bow on each side, taper it off about a foot from stern into the bumper and build it up about 5 planks till you get to the very center of the stern bumper. Less bending and curving of the planks required. See my pictuer in previous posts on what that looks like.

I did not use any epoxy on planking the hull. Only CA glue. Much faster and keeps the inside of the hull looking really good with on globs of epoxy building up. After you put a layer of fiber glass cloth on the ouside of the hull to tie it all together for strength and then paint a layer of epoxy over the inside of the hull, you get a really good finish that shows off the planks from the inside.

LynxRA

Grinder-RCU,

Where do you find these (removable bearing support for the skeg) for the rudder? Phoenix Hobby Shops are the pits for anything for RC Boats.

Lynx

Kaymac

Dallas, I like the idea of not putting anything on the inside planking as it does look better clean, however, when I tried it on my tug, inevitably the inside wood got wet...don't ask how..[:@] and found that the moisture will creep through to the outside and will not only release the CA, it will separate the glass layer from the wet wood. The result was to strip the loose glass and redo the hull.....and I gave in to completely sealing the inside planking.

grinder-RCU

My Feedback: (1)

Are you referring to pg 8 post 189 of this thread with the pics of my smaller tug?. That tug is from Aquacraft and is only 31" hull. I'm going to use the same method for my large tug with the bearing support idea. Except i will have to get one custom made for my scale as none are available that large. Should be a pretty straight forward machining job. The idea being that the bearing block has a screw to make removing easier for the rudder maintenance.

Grinder.

LynxRA

Do you have a picture of what I may have to have made also? It sure would be a lot easier by the sound of it taking the rudder off if needed for maintenance.

Lynx

dallas2254

I used epoxy all over the inside of the hull to keep the water from swelling the balsa (if water got inside the hull). Fortunately between the blue marine grease that I pressed into the shaft and a good seal on the bow thruster, there is no other way for water to get in to the hull other than over the top of the hull with the cabin off.

With regards to the rudder attachment, I did not consider the use of a rudder bearing block. Never noticed it on Joe's model. I have enclosed the pictures of what I ended up doing to lock the rudder in to the 3/16th shaft running through the next larger size of brass tubing as a bearing.

I soldered a brass bolt to the bottom of the rudder and ran that through the keel support and put locking nuts (going to replace with a nyloc nut), then soldered a 2 inch brass tube to the top of the rudder that the 3/16 rod slides into from the top. I noticed that drive couplings made for my 36 inch Shelly Foss would fit perfectly over the top of the rudder while attached to the 3/16 rod so I slipped that over and then for added measure put a 3/16 brass collar under on top of that to keep the shaft from going up (which adds redundancy to the lock nuts at the bottom of the keel). I have no play out of this set up. The brass rudder is about the thickness of the brass drive coupling opening.

I have included pictures of all of this below

grinder-RCU

My Feedback: (1)

Here is a pic. You simply unscrew the screw and remove the bearing block, unscrew the tiller arm grub screw at the top and the rudder should drop down out of the way. Once the rudder is out of the way you can remove the prop and shaft.

grinder-RCU

My Feedback: (1)

Hi Dallas i see in one pic of your tiller arm you have of the grub screw, I hope you have a flat spot on the rudder shaft to prevent the grub screw from slipping.

Grinder.

dallas2254

Joe,

I have a lot of flat spots and a bald spot but I am not sure if one of them is on the rudder shaft. [8D] I will have to check on that on. Thanks for the recommendation. I know that I have put one on my drive shaft due to the amount of torque that prop desires.

D

dallas2254

Lynx sent a email this morning and motivated me to put a couple hours into my tug. I have been waterskiing every morning and have not had time to work on the tugs.

I transplanted a new Pittman 3700 in place of the MFA motor today. Then the power supply failed so I did not have a chance to launch the tug to try the new motor. I was able to use the 2:1 pully system off the MFA platform. I figure the Pittman 3700 has enough torque to run the 5.1 inch prop direct drive but I would prefer to scale the RPM to around half of that so this should do the job.

I let the motor and prop dry run for 10 minutes and seem to do well.

This tug will not be able to keep up with my 76 inch Dual prop Shelly Foss obviously which will be direct drive Pittman 3700's or american bosch motors.

grinder-RCU

My Feedback: (1)

Did you make your own alum bracket for the motor?. I need a couple for mine.

Grinder-RCU