Hi folks,

Anyone have experience with building or running a Dumas 48" Fiberglass PT 109?
I just ordered one. I'd like to know if somebody might have any info or suggestions for the difficulty they had putting it together, or what running gear they used, is there enough room to add a third rudder? how's the detail? And how's the performance?
Thanks

Mike S.

Wow, seems like I just answered a similar question.

A company called "Mack" markets a drive system,
http://www.mackproductsrc.com/1233%20PT%20109%20S.htm
http://www.mackproductsrc.com/pwr_pkg_p2.htm

However, they are only dual shaft.
The two that I have seen run, perform beautifully. I don't recall the rudder setup though.
One guy actually lit all the dials.

In my opinion anything is possible if you can build it small enough.
So building it with a triple rudder would be nice, but it isn't really necessary for boat handling.

I have a video of a 48" glass PT:

http://www.rcpics.net/view_single.php?medid=18621

Hey Thanks that was great, I think I will be very pleased.
Mike

[X(] I got it yesterday, to tell the truth it seems a little overwelming. This may take a little while to build. I don't have a lot of experience with boats.

Should I start by installing the engines and running gear? Then build around it, I'm a little worried that my big hands won't be nimble enough, once the decking is in place. The plans do show a scale for a 3rd rudder so for scales sake I'm going to install it.

If I use three 12v motors, how long can I expect the batteries to run before they run down?

Any help matters thanks,

Mike

Mike,
As to the order of construction. It just makes sense to do the 'in hull' stuff while the hull is open (unless you just enjoy doing 'microsurgury'). If you break it down into the 'in hull' stuff, and the 'above hull' stuff, you can make things managible. The absolute best advice anyone can give you is to go through the plans/instructions several times, and build the thing in your mind. Try to figure out where the 'problem' areas are, what's going to be a 'pain' to do, and what ~should~ I have done before I got to this point? (Not that any of us have ever had to back-up and do something over, right?) None of it is impossible, some things just require more thought than others. And when you look back on it later, the most fun was in the 'getting there'.
Have fun and good luck...
- 'Doc

PS - It's sort of like plumbing. Do you want to do it before you put down the floor? Or after, when you have to crawl under there? Either will work...

Thanks Doc, makes sense to me.

Thats what I'm doing .... pouring over the plans, I brought them to work to study. (good thing I have alotta down time eh!).

Looks like there are several stages I can work before installing the deck. I'll install the running gear before building the deck.

thanks again,
Mike

Re: motors and running time.

It is a big variable dependant on the motors you are running, and their rated amp draw, and the size, amperage of the battery(s) you are able to fit into the boat.

You should be able to get a rough idea by adding the motors amperage rating and dividing the batteries amp rating by that number.

IE; If the motors draw 0.5 amps apiece, then if they are wired in parallel then all three should draw 1.5 amps. If you have a 12volt-1.9ah gel cell then that battery should be able to run the motors for about an hour and a quarter.

Mike,
About batteries. They make very nice ballast (if any ballast is required)! No one ever has 'all' the battery that they wish they had, and substituting another battery or two for any ballast you might need is an alternative.
Also, if you have the option, using geared motor(s) instead of directly driven props, ~usually~ means less battery drain and longer running times. You have to balance that against the higher cost and complexity of geared motor systems, though, and there are other 'draw-backs' to geared motor systems (noise mainly). That's not a suggestion, just an alternative.
- Doc

Mike,
I have 3 of the Dumas PT boats and you're absolutely right about the amount of work it's going to take you as there is a lot of building that is needed if you go strictly per the instructions
As for the drive shafts my first model had three screws but I ended up not using the center screw as the power to weight was just not worth it.
All of my PT boats were powered using only two screws with Graupner 12V Speed 700BB motors and twin MCD speed controllers. With this setup the speeds are awesome and I run with a 12V gel cell battery which is a little heavier than a nicad pack but I can get more that double the run time.
Two of my hulls use a modified shaft assembly which consists of a strut and a shorter stuffing box. This is more to scale bit you need to make sure that you do the alignment between the struts the shafts and the stuffing boxs otherwise you get some binding which will cause drag and a reduction in speed and run time. My first boats running gear was done per the Dumas plans and i was not too happy with the way it looked.
I went the expensive route and build my second and third hulls using some aftermarket fittings that you can get from such places as Mosquito Boat Hobbies, HR Products. I've purchased several fitting packages from Mosquito Boat Hobbies and am very happy with the quality and service. One word of caution is these pieces can be expensive. My last fittings kit was around $400 and was a Christmas gift from my wife in 2002. Boy was I surprised!
If you're a stickler for scale the Dumas kit has several small problems that are not to scale on their hulls. To correct this you need to rework the bow which is initially a little scary but definite well worth the fitting of the deck to the hull.

As for your rudders I found that the scale rudders did not give me the control that I needed so I over sized them slightly but still kept te same shape. This made a world of difference in being able to maneuver the boat at slower speeds. To help I have a Nautical Commander Ace radio with twin throttle sticks with twin speed controllers which allows me to operate each motor independently. I can pivot this boat in its own length.
Let me know if you want any more information.
Tom

Mike:
While you're looking at the kit plans, you might also want to dig into a little backgroung of the boat. JFK got all of the "ink" but that's not where the history was made.
There are (2) links you should look into:
WWW.FLOATINGDRYDOCK.COM
WWW.PT-BOAT.COM (John Drain, in Australia, is SERIOUSLY into PT modeling)
You might also want to consider trimming the boat as "late war" instead of the initial versions, which used a civil war cannon (black powder) to luanch WW1 torpedos which were 70 % defective.
And, on all of the photos I have, and have seen, no one ever deployed the "life lines" on the front of the boat.
I'm on my third Dumas kit. One 48" which is just too big for an apartment dweller. and two of the 33" hull kits. The 33" are being trimmed as late war, with "roll off" torpedos, Three cannons, and rocket luunchers.
Good luck with your kit, and WATCH OUT FOR THE SPLINTERS ! (Dumas seems to be exceptionally good at those)

Stay in touch.
Richard (in Cincinnati, Oh)

There are some really nice detailing ideas including paint schemes for the PT 109 in "Ships in Scale: The shipmodeler's home port." July /August 2003 Volume XIV Number 4. Reprints are available by order. The article was written by Whit Vye. It provides several detailing plans for the mast, chart house, and guns as well as a really nice camo paint scheme that is like the real thing. I would also recommend late war detailing since everything seems so much more substantial. Have you ever thought about building it for combat with servo actuated bb cannons. It could be a blast - literally.

Here's some more info for painting & research:

1) PT Boats at War - World War 2 to Vietnam. Norman Polmar & Samual Loring Morison. MBI Publishing ISBN = 0-7603-0499-9
2) PT Boats in Action. By T. Garth Connelly Illustrated by Joe Sewell. Squadron/Signal Publications Warships #7 ISBN = 0-89747-312-4

You can go to almost any bookstore & order using the ISBN or try online. I have built a few PT Boats & these books are invaluable. They show everything from early to late weapon installation to paint schemes to deployment & final history on each boat.

Also, if choosing a battery make sure to take weight into consideration - you don't want your boat running as low in the water as the boat in that video. You want the boat to 'get on step' & rise up out of the water when running. This will not only help in scale appearance but also run time since you are more on top of the water instead of trying to push through it. I like to use a smaller gel battery that can be mounted in any direction stuffed forward in the hull. I always build the bottom separate from the top. Install all of the running gear & only remove what you have to to get it painted. I paint the top separate from the bottom. Then install the decking & top & touch up the seam if necessary where they meet.

Good luck!

Hi, I just received my Dumas 48" and found all of your posts very helpful. I have a lot of questions but I'll beginning with working with fiberglass. I'm not sure where to begin, does some one out there have a sequence, i.e. which resin do I begin with? do I use f/g cloth or f/g pieces? This boat was expensive and I don't want to screw it up.

Hi: There's just something about 3 motors in a PT boat... Gotta have them. I've built a scratch built British Vosper MTB, at 1/14 scale. It's 60 inches long and powerd by three 18vdc drill motors. Each motor turns direct-drive a 1 3/4" 3 bladed prop. The motors are controlled through Proboat ESCs. Other PT boat builders have had issues with not enough rudder authority sticking with scale sized units. I made mine a little bigger anticipating that problem. While only running the two motors in the Dumas PT works fine, there might weight penalties adding a 3d motor, esc and battery. But then, this isn't a raceboat. My boat will be powered by 3, 10 cell 4000mAh NiMH packs.

Good luck with your boat.

Mike

When you completed your Midwest PT-109, did you change the electric motors so that the motors both rotated inboard and outboard vice the stock setup?