Triple Screw Boat

[Queequeg QuintParticipant @queequegquint38270]

I am attempting to build a triple-screw boat that actually works. Here is the hull design that I'm working with. It's 45-inches long, 14-inches wide.

Here are pics of the hull being built:

I will post pics on this thread as things progress. Of course, I am open to suggestions and constructive (no pun intended)-criticism along the way.

[Queequeg QuintParticipant @queequegquint38270]

[Kev.WParticipant @kev-w]

I have a 'triple screw boat' it's approx 1070mm long & 175mm wide, it came with 3 'Jumbo 2000' brushed motors, driving 3, 3 bladed 45mm props.

It was rubbish performance, so swapped the motors out for 3 brushless motors,

Using 3, 3cell lipos these proved to be too much , so removed the centre motor & prop (leaving the shaft in, but sealed), now run it on the 2 outer shafts, contra rotating & it does really well as regards scale speed (thumb control helps) and gives scale speed without rolling in the turns.

The boat in question is an old 'Graupner Weisel'

Edited By Kev.W on 26/06/2021 00:12:28

[Paul TParticipant @pault84577]

I had a lot of fun getting a triple setup in my Red Leader MTB.

In order to maintain a shallow pitch on the prop shafts I had to invert the motors and hang them upside down on a special frame.

To maximise the slow speed steering I fitted over size rudders.

[Queequeg QuintParticipant @queequegquint38270]

Posted by Paul T on 26/06/2021 15:50:08:

I had a lot of fun getting a triple setup in my Red Leader MTB.

In order to maintain a shallow pitch on the prop shafts I had to invert the motors and hang them upside down on a special frame.

To maximise the slow speed steering I fitted over size rudders.

 

Lovely set up. I am inspired! How does it handle in the water? Do you control the motors individually? FYI: My battery-friends have built me a 12-volt NiMH which can handle a 30Amp current and has 8,400mAh. I'm taking this project one-step-at-a-time. I'm still keen on using three MFA 800s, but am going to study the hull in person before I go forward with the motor-decision.

Edited By Queequeg Quint on 26/06/2021 16:09:49

[Richard SimpsonParticipant @richardsimpson88330]

30 amps, that's a domestic ring main! You should have some fun with that.

[Paul TParticipant @pault84577]

I used an Action System that Dave Milbourn built for me,

Combined ESC & Mixer provided different levels of power to each motor to enhance the steering..

It handled like a dream and was quite fast even with 600 size brushed motors, mind you I was pushing 18v through them.

Sadly Dave is no longer with us but his layout designs are here Dave sold Action to the Component Shop link who are very helpful in advising the correct system for your setup.

[Queequeg QuintParticipant @queequegquint38270]

The hull arrived today.

Edited By Queequeg Quint on 03/07/2021 18:55:15

[Tim RoweParticipant @timrowe83142]

Helllo QQ

I wonder if there is any particular reason that you want triple screw?

Your hull moulding is very clearly designed for twin screw and to add a third it looks like you would have to shorten the centreline skeg.

Going for three will add complication for no significant advantage if any. If something more complex is your aim however – go for it!

Tim R

[ashley needhamParticipant @ashleyneedham69188]

Q wants three props. That’s what he wants what he really really wants.

Two just does not hit the spot!

Ashley

[Queequeg QuintParticipant @queequegquint38270]

Here are the latest photos and a video narrated by a relative. Cabin is being built as we speak. So far.. it's working!

Video: https://www.youtube.com/watch?v=WyTuyPHFilA

 

 

Edited By Queequeg Quint on 14/07/2022 16:07:58

[John W EParticipant @johnwe]

Hi there,

Not wanting to burst your bubble or rain on your parade as they say – but – as you may already know the shape of the hull you are using does not lend itself to be driven at any great speed. But, judging by the propellers and the motors combination you are using, along with the voltage will subsequently make for a bad model to handle at any speed further than the hulls design speed. Hey ho though, it is your model – and that is what modelling is all about – enjoyment. Sail in a shallow lake though, where waders are available

Years ago, when Electronize was in full swing, they used to produce a speed controller which was very basic and you could, literally, switch the signal on and off at any throttle settings and it would not affect the setup of the speed controller. I used this in several models – one of mine being the RAF Crash Tender, where I used an ACTion mixer to control 2 Electronize speed controllers on the outboard motors and the centre motor could be switched on and off independently so I could tootle round the lake running 2 props and when I wanted it to take off like a NASA rocket I switched the 3rd motor in like reheat. Sadly, though, I do not think there are any speed controllers now on the market which allow you to tamper with the signal, Unless of course you can get hold of Electronize speed controllers.

Couple of pics of the internals of the RAF Crash tender.

John

[John W EParticipant @johnwe]

Edited By John W E on 15/07/2022 10:41:16

[Richard SimpsonParticipant @richardsimpson88330]

Mine is just an observation and in no way a critisism but, in real practice the centre shaft would not protrude as much as yours does for very sound engineering reasons. In your model the engineering concerns are not relevant however it does leave you with an arrangement that, to me, just looks a little odd. Extending the keel to come up to the rear of the propeller would be way too much work so it would be interesting to see what it would look like if you simply pushed the centre propeller back a little to reduce the amount of exposed unsupported shaft.

You may well then think that it looks odd not having the props in line but, as I said I simply see it from an engineering perspective.

[ashley needhamParticipant @ashleyneedham69188]

Go for it Q. It’s your boat, and I rather like the row of props!

I don’t think it will be so fast as to be dangerous on the water, but you may want to ramp up the speed slowly and keep the weight low, and superstructure light.

Ashley

[Queequeg QuintParticipant @queequegquint38270]

Finally getting to work on the frames…

[ashley needhamParticipant @ashleyneedham69188]

Getting there Q!

Motr control may be your next issue, three 800’s will not draw excessive current so likely a 30A esc will do, but I would put the hull in the water and try one motor straight across a battery and use a meter to see how much current is being drawn so that you can gauge the total current draw first.

Ashley

Edited By ashley needham on 28/03/2023 09:00:04

[Queequeg QuintParticipant @queequegquint38270]

Cabin being built.

[ashley needhamParticipant @ashleyneedham69188]

Q. Nice shape on the cabin.

The very large warship behind….pictures and info please?. In fact some shots of the others would be nice!

Ashley

[Queequeg QuintParticipant @queequegquint38270]

Posted by ashley needham on 22/06/2023 08:06:21:

Q. Nice shape on the cabin.

The very large warship behind….pictures and info please?. In fact some shots of the others would be nice!

Ashley

Thanks, Ashley. For information on the boats in the background, see here: http://www.homeportmodels.com

[Queequeg QuintParticipant @queequegquint38270]

Posted by Richard Simpson on 15/07/2022 10:56:02:

Mine is just an observation and in no way a critisism but, in real practice the centre shaft would not protrude as much as yours does for very sound engineering reasons. In your model the engineering concerns are not relevant however it does leave you with an arrangement that, to me, just looks a little odd. Extending the keel to come up to the rear of the propeller would be way too much work so it would be interesting to see what it would look like if you simply pushed the centre propeller back a little to reduce the amount of exposed unsupported shaft.

You may well then think that it looks odd not having the props in line but, as I said I simply see it from an engineering perspective.

Can you explain the engineering reasons for your suggestion? I'm curious.

[Queequeg QuintParticipant @queequegquint38270]

[Queequeg QuintParticipant @queequegquint38270]

[ashley needhamParticipant @ashleyneedham69188]

Q. That’s a good looking top you have there….and the boat is not bad either!

Great display of warships nicely shown against the wood background.

Ashley

[Queequeg QuintParticipant @queequegquint38270]

Behold, my triple-Screw boat, the Dolphin!

Here is the Dolphin next to the Illusion. The Illusion is about 36-inches long. As you can tell, the Dolphin is BIG!

On the water!

Edited By Queequeg Quint on 25/08/2023 01:43:03

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