chris moore

iTrader: (96)

Hey guys I need some help with an old wooden boat kit. I bought this like twenty+ yrs ago and built the hull but got sidetracked and never finished the boat or bought the running gear. The boat is an old Dumas 20" V hull boat that was originaly designed for a gas motor. Does anyone know where I might be able to get the correct running gear and how easy/hard would it be to convert to brushless electric.

Chris

chunk t

I'd check with Fuller's Fast Electric or Off Shore. Which kit is it? the SHORT STUFF? Many of those older Dumas kits were designed for sub-surface drive, all FE (fast electric) stuff is surface drive. This just means you need to do a litle homework and planning before you install the stuffing tube and radio box. Being electric I suspect your boat will carry a bit more weight, so you will need plan the location of you motor, batteries & radio so you keep the balance correct (29-33% total length forward of the tronsome).

I'm guessing this is your first mono, with that thought in mind you will need at least 1 turn fin (2 if you want sharp handling in both directions, mounts to transom), rudder & trim plates (trim plates will help control porpusing & bow height for the less experienced boater).

have fum

OffshoreElectrc

I think you emailed me about this.

I think the first place to start is Dumas.

If you want a budget setup, you can install a 4mm straight shaft and offset rudder.

chris moore

iTrader: (96)

Thanks for the info Chuck, the kit I have is an SKdaddle 20 kit and yes it was designed for sub-surface gear.



Offshore: Yes I did send you an email on this issue, but I've been unable to get ahold of Dumas as of yet. However I'm not sure how much help thay will be as this kit is very old and I wnat to run a brushless electric setup. The orignal runing gear; if even avalible; ws designed for gas and I doubt that it would work for what I have in mind. Keep in mind that other than this boat which I built 20yrs ago I have zero RC boat experience so when you say run a straight shaft and offset rudder are you refering to a kit you stock or just using off the shelf parts?

Thanks
Chris

chunk t

Chris,

Gas or electric, the running hardware is basicly the same only the motor mount and stuffing tube length will vary. On a mono you have two ways to go, straight shaft or flex shaft. Generally the straight shaft would be used on a sub surface drive where a flex shaft would be used on a surface drive set-up. Both set-ups can give you a boat that can get up and move out, but most hardware and props on the market are designed around a surface drive set-up. My recomendation would be to set the hull up as surface drive, the SKDaddle has a shallower "V" & shallower draft than the Short Stuff. More conducive to a surface drive set-up.

My opinion is only one of many, but here's what I'd do...

1) try different locations for the motor, battery & radio w/in the hull to get everything to balance correctly (29%-33% of total hull length, forward of the transome) this will help you determine where you want to locate the motor & the length of the stuffing tube in side the hull.

2) I'd start off by using a 3/16" brass tube (w/o Teflon liner) as a stuffing tube and allow it to protrude about 1.5" beyond the transome to act as a strut (I do this on my 3.5cc nitro mono's). The stuffing tube should exit the transome 1/16"-3/32" to the left of the centerline (if you mount the motor on the centerline of the hull this will place about 1-degree of off-set to the left, helping counter "prop-walk") & 1/4" above the transome's lowest point (these measurements are relative to the center of the stuffing tube). I like the brass tube because it is pretty low friction, cheep & you can easily bend it (align) by hand to dial in the ride.

3) Go to OffShore's web sight and purchase the Octura 3" rudder & long bracket. I'd mount the rudder to the right of the prop shaft half-way between the prop shaft and RH edge of the transome.

4) use a .130" flex shaft (oct-oc130R-24c from OffShore). a bit over kill by some standards, but I feel the extra ridgidity & resistance to wind-up make it a better choice for electric surface drive at this size. This will also allow you to use a 3/16" prop shaft which gives you a larger selection of props.

5) you need at least 1 turn fin (RH) for right turns. Ask OffShore what he's got.

6) you can make your own motor mount out of 1/16" aluminum sheet if you don't see anything on the market that will fit your hull.

The only other suggestions I'd make would be make sure your radio box is easy to access and seal.

OffShore & I can field any other questions you come up with.

later.

chris moore

iTrader: (96)

Cool thats exactly the info I needed, thanks for your help. I'll take a look tomorrow and see how/where things line up for a dry fit and then go shopping.

HoaRC

iTrader: (1)

The boat forum on modelboatmayhem and rcgroups are the best!!!! people there WILL help you.

chris moore

iTrader: (96)

Thanks for all the help guys, turns out that Fullers is local(in town) so I stopped by and picked up the parts I needed today I'll post some pics when I'm done.