4 or 5 motors

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4 or 5 motors

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26 November 2014 at 19:04 #2447
Queequeg Quint
Participant
@queequegquint38270
new boat idea
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26 November 2014 at 19:04 #53853
Queequeg Quint
Participant
@queequegquint38270
I'm fixing to build a new boat. A big one with 4 or 5 motors and props. Has anyone ever done something like that, and do you have any advice?
26 November 2014 at 19:40 #53856
Bob Abell 2
Participant
@bobabell2
Hello Queeq

I am building a boat with four motors

Take a look at our thread called……."Vintage Gentleman`s Cruiser"

It`s just down the page from this thread

Tell me about your idea, please

Bob
26 November 2014 at 20:30 #53859
Queequeg Quint
Participant
@queequegquint38270
Hi Bob,

I'm thinking of maybe a tug or a big fishing boat. I'll go with 4 motors for the sake of balance

But I need advice on these things:

1. 4 rudders behind each prop, or 2 rudders in between each set of 2 props?

2. How should the hull bottom be setup? I have 3 lobster boats and they all have center keels, with the propshaft running through the keel. But with 4 prop shafts, should the hull be identical to the lobster boats, and just route the propshafts on either side of the keel?

Some pics of twin-motor tugboats seem to show two keels, with propshafts running through them. So… I'm not sure of the best design. If someone has a pic of multiple-motor boats, that would be helpful.

3. As for the motor-setup… I'm thinking of the MFA 800 at 12v…. or maybe a gear reduced 540-size motor. If I use 4 big motors…. that means lots of power consumption to worry about. 540-size would give me plenty of space to work worth, and reduce the current. But I do want some huge props on this boat….

One of my lobster boats has a 65mm 5-blade prop with the MFA 850 belt drive reduction setup. And I kinda want to spin some props around that size… although… I'm not sure.

OK…. any advice you have would be helpful.
26 November 2014 at 21:02 #53861
Bob Abell 2
Participant
@bobabell2
Hello Queeq

I think you may not have found my proposed motor drives…..As the thread is quite large

Here are my motor drives in their early stages….

Just keep popping in

Bob
26 November 2014 at 22:31 #53865
Queequeg Quint
Participant
@queequegquint38270
I saw the thread, but did not see your motor setups.

Wow!! That is amazing.
27 November 2014 at 08:01 #53867
Bob Abell 2
Participant
@bobabell2
Hello Queek

Each pair of MFA 850 motors will drive a single LH 60mm or 70mm dia prop and each prop will have a rudder

We have a single keel

Bob
27 November 2014 at 14:50 #53883
Paul T
Participant
@pault84577
Are you looking for speed or brute power?
27 November 2014 at 15:38 #53887
Queequeg Quint
Participant
@queequegquint38270
I'm looking for brute power. I'm a fan of MFA Como motors.

Haven't designed the hull yet, but that might depend on the motor setup. If I go with the belt driven 800 or 850, I reckon I'll need lots of space.

Also, I want 4 motors turning 4 props.
27 November 2014 at 15:56 #53888
Paul T
Participant
@pault84577
For brute power read this thread **LINK** it gets more interesting as the project develops and ends up with 4 huge motors and 4 heavy duty pumps.

Edited By Paul T on 27/11/2014 15:58:45
27 November 2014 at 16:28 #53890
Queequeg Quint
Participant
@queequegquint38270
Wow Paul!! The Mighty Thor is truly powerful. My heaviest, and most powerful boat is the Ambassador. It's just about 3 feet long. MFA 850 with belt drive reduction turning a 65mm 5-blade prop. It was a veritable miracle how I mounted the motor!

My big boat will have to compete with the Ambassador.

Right now, I'm thinking of 4 MFA 800s, direct-driving 4 55mm props. I use the 800/55mm setup for my lobster boat Illusion and it's perfect.
27 November 2014 at 16:57 #53891
Queequeg Quint
Participant
@queequegquint38270
I just had this thought. Instead of a new boat, maybe I could jam in two more motors into the Ambassador. Would it be OK to add twin 540 motors, geared 2.5:1 turing 2 45 mm props… humming along with the 850 turning the 65 mm prop?

What effect would that have on the propulsion?
27 November 2014 at 17:59 #53893
Paul T
Participant
@pault84577
Queequeg

Adding more motors sometimes just means adding more weight and the extra propulsion is lost in pushing the extra weight about.

It is also possible that the hull isn't capable of handling any more motors and so adding additional motors and propellers will simply 'boil the water' without providing any more thrust.

Can you post some more photos of your model so that we can see the shape and style of the hull.

Paul

ps I like the mix of nautical references, does this mean anything to you?
27 November 2014 at 18:38 #53896
Queequeg Quint
Participant
@queequegquint38270
Paul,

That picture you posted is the USS Enterprise… Sovereign class!!! Actually, if I make a big beast of a boat, I might name it "The Sovereign"…

Based on what you suggest… then maybe I should indeed build a whole new boat. With 4 850s geared down, turning 4 75mm props!!

My Ambassador is basically what we call here in America a Novi Hull. Not much space left, but I think I could jam in some 540s…..

(Ambassador on far left)
27 November 2014 at 19:09 #53900
Paul T
Participant
@pault84577
Queequeg

I have had a look at the specs of the Novi style of hull and whilst they have excellent sea keeping qualities I don't think that they are suited to having multiple motors.

For a powerful brute of a boat you will need a deep hull with plenty of mass so to achieve your dream you might need a 'bigger boat' (a line from a film?)

Paul
27 November 2014 at 23:16 #53918
Queequeg Quint
Participant
@queequegquint38270
Yes, a "bigger boat." Yup, that's from Jaws. And that's the Orca in my pics. That boat is made of wood with fiberglass resin and cloth over it.

OK…. I'll go back to the drawing board.

I would like to see pics of the bottom of multiple-motor boats, if you have any.
28 November 2014 at 11:42 #53929
Paul T
Participant
@pault84577
This is a triple set up on a MTB that I built last year
22 July 2015 at 21:39 #59328
Queequeg Quint
Participant
@queequegquint38270
Paul,

What shape of hull do you reckon will be suitable for multiple motors?
23 July 2015 at 08:09 #59336
ashley needham
Participant
@ashleyneedham69188
Something with a wide flat back end !!!

Think of a drug runners boat with all those outboards on the back….

Ashley (stating the obvious)
23 July 2015 at 18:09 #59348
Paul T
Participant
@pault84577
The shape of hull depends upon what you want the boat to do

For example a super fast boat will have a different hull to a powerful towing tug.

Let me know what the requirements are and roughly what length, width etc. and I will be glad to help.

Paul
6 August 2015 at 20:59 #59629
Queequeg Quint
Participant
@queequegquint38270
I'm thinking more like a tug.
7 August 2015 at 11:28 #59635
Paul T
Participant
@pault84577
Tug hulls are wide and deep to give them mass in the water

Putting multiple heavy motors in a hull like this would produce a very powerful model.

Paul
27 January 2016 at 16:49 #63081
Queequeg Quint
Participant
@queequegquint38270
I haven't started this project yet. Paul, where can I get a hull like the one in your picture? It would have to be quite large, so I can fit in 4 MFA 850s with belt-drive unit (or maybe 3, if 4 is a bit too ambitious).

The bloke who made my Orca, Illusion, and Ambassador hulls can make a big hull, but not like the design in your pictures.

Edited By Queequeg Quint on 27/01/2016 16:51:38
27 January 2016 at 17:33 #63082
Dave Milbourn
Participant
@davemilbourn48782
QQ

Try this one – and sit down while you check the cost of shipping. **LINK**

Dave M
27 January 2016 at 18:13 #63083
Colin Bishop
Moderator
@colinbishop34627
I can't really see the logic of putting in multiple motors, after all they don't make more powerful cars by putting in extra engines, they just use a bigger one. Saves space and no transmission losses.

Colin
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