Exactamente John, 👍
You beat me to it!
I'm experimenting with the P94 to improve the 'cornering' of my long thin, 10:1 LoA to Beam ratio, destroyer with twin 540s, and will use one (or the Brushless P40 version) in my triple screw PTB.
Beauty of the hardware mixer is that you can switch off all the aircraft / heli mixer functions at the TX and just use one stick for both rudder and throttle! 'One thumb control'.
Much easier and cheaper than buying a dedicated TX etc. 😉
OK; if you want independent control of centre / outer screws you need an extra ESC (disconnect the 3rd output of P94) and a second throttle stick. But you can still use the P94 to spin the boat 👍
NiMH vs SLA? 👍 Going LiPo would improve the power/weight ratio even further 😊
Cheers, Doug 😎

hi there Chewi
having read through your postings and watching your video - I am not sure if you have the ACTion P94 set up correctly. You should be able to spin that model round on the spot as the P94 contains a rudder motor mixer built into it. However, be warned, the P94 doesnt like certain 2.4 transmitter sets. Basically, you have to set your transmitter back to zero manufacture settings with no mixing at all on your transmitter to get it working - and - its all done in the ESC - I have built several triple screw vessels myself - the RAF63and the MTBs and basically what I used to do there is use the old Electronize speed controllers from the 90s which dont have the pre-programmed chips in them so that I could switch the signal on and off to the speed controller, thus allowing me to control the centre prop by switching the signal off and on. So, when I wanted speed I ran on all 3 props but when I wanted to manouvre I switched the centre prop off and allowed the 2 outboard motors to spin the vessel with the rudders, using mixers.

In this particular model - I would ditch the gelcel battery and go for a Ni-MH battery and the 9.6 volt 500 mAh - 3 of these batteries one for each motor should give you ample run time.


John

Have never aspired to aircraft, enjoy boats too much.
I use a Fysky (Turnigy) FS 10 Tx which is very competitively priced. This Tx can be programmed for up to 20 models, so use it for several different boats, some multi-screwed, others single. Some with 'elevon' throttles, some conventional.
Think this Tx would have the capability to be used for both aircraft and boats. Worth a look rather than buying a unique Tx.

Sounds like you need to have a dedicated TX for the boat. I had a similar problem as I fly planes also. I bought a Hobby King HK6s mode 1 which is a basic 6CH but is easy to convert to twin throttles for boats (I have 2,- 1 for smaller planes and 1 for boats + a 6x, 9x and 2 9XRs). Makes life a whole lot simpler not having to use relays and switches for motors. The other TX is the Fly Sky 9X (Turnigy 9X, IMax 9X) which has more switches and functions (plus easy to find extra RXs outside HK,- 3ch, 4ch, 6ch,which suit) or if you want overkill, a TGY 9XR pro and JR module, which has everything you will NEVER need on a boat . Maybe you could use a program to pulse lights, (I have it lowering the flaps on my Cub in 2 stages in small steps /pulses and slow stepless up for eg,) or perhaps have the center motor only coming in over 1/2 throttle through a separate RX,- options are endless.
I think the HK 6s is the best if you just need a 6CH or the 9X for more features. You can use the rotary switch (6s) through a Sky RC remote switch (eg) to turn on lights etc plus the toggle sw for another function. Just depends on the $$ really
Not sure if you are using Lipos, brushed or brushless setup but either way sounds like 2x 3s 3000mah 20c lipos should work, especially if your motors are brushed 12v , also maybe try reducing the prop pitch or diam to take a bit of load off the battery/s. Depends obviously on a number of things such as space, motor type (no of poles, KV, size etc), boat weight, battery type and capacity/discharge rate etc. Lipos are by far the best option for powering models.

I am using a Flysky 10 channel Mode 2 Tx, set up for 'elevon' control on the outer screws. The centre is controlled with the LH throttle lever.
On the last day out, got around 50 mins of battery life running the centre screw continuously and the outers around 30% of time.
Powertrain is:
2 x ZIPPY Compact 2200mAh 3S 35C Lipo Pack each powers one outer shaft and one also powers the centre.
Outer shafts : 2 x Turnigy AquaStar 2842-2800KV Water Cooled Brushless Outrunner Motor
2 x HobbyKing 50A Boat ESC 4A UBEC
Centre Shaft : 1 x 550 Brushed motor
1 x Quickrun 1080 ESC
All shafts have 35mm brass screws
Model is about 35" OL length and performs well. She planes just like the original Brave Borderer.

Hi,at the moment the tx is set to mode 2 (throttle left)as I also use it for flying helicopters and planes,it’s a spektrum dx7,it was set with the throttle on the elevator stick but this became confusing as it not what I’ve been used to,will probably look for a tx just for this with a centring left stick throttle,mode 1,I’ve looked into the dx7 with the hope of creating a program mix but haven’t come up with any thing yet.In the model I’ve used a 12v 7ah battery but got less than 10 mins any ideas for longer running time ?obviously a bigger amp hour battery equals longer time but adds more weight.

Did this on my Brave Borderer. 2 x brushless motors on outboard screws and brushed on centre using a third ESC.
Works well

Nice work, looks great and runs really well. Have you thought of using twin ESCs on the outboard motors and converting the left stick (elevator - mode 1 set or vice versa for mode 2 ) to twin throttles. Most TXs are easy to convert, just a matter of removing the centering spring and making another ratchet plate for throttle use, - then plug your second ESC into the previous elevator plug on your RX . Would make your maneuvering easier in tight spots with a long narrow boat (plus adds to the scale effect.)