Thank you for pointing me in a direction. Im really quite unfamiliar with most boat terms. Further to your help I did some research on "skeg" & found this which is also a keel extension but projecting downwards from the hull, faired a bit more than just a bearing at the base of the rudder

Spot on Martin,
Very useful on boats that sit on the bottom at low tide in shallow harbours.
Cheers Colin.

Hi marky,
Looks you are going to enjoy that build.
Good luck.
I will be watching your progress.

Martin.

Hi RodC,
I think it is called a 'Skeg'

But knowing me I am probably wrong LOL!

Martin.

What do you call it where the bottom of the rudder is supported like that ??

Hi Fred , many moons ago before I retired I managed workshops at a university I'm going to pop in and see if they would be kind enough to laser cut it for me ,if not I'll go back and get the wood pack saying that the cost of ply and the wee bottle of Amber nectar i'm going to use as an inducement (bribe) the wood pack May work out cheaper.
Cheers Marky👍

Hi Marky
Did you also go for the wood pack?
Fred

Last post should have read, teachests lovingly converted.
Cheers Colin.
PS, can't edit my posts.

TLC (teachers lovingly converted.)
Love it shipmate, cheers Colin.

If your looking for a good motor then I would say look at the Torpedo 500 6.1 geared motor . best place to fit motor depends on what your building, tugs etc need there propshaft as straight as possible along the hull whereas fast types need propshaft at around a 10 degree angle

Thanks Dave , having only built static previously it's a bit of a leap for me.

Hi Marky
We have several TID models in our club and I have a fibreglass hull (36") and plan purchased at the Boat Museum several years ago. I will build one day.
You need to select the motor before fitting the propshaft as for best results you need to achieve a straight drive train. I would use a 555 brushed motor as this will give plenty of Tork with a 6v battery. As you can see from the plan the propshaft is basically parallel to the keel and needs to extend far enough into the hull to allow the motor to sit on its mount. It would be a good idea to fit the prop at the same time to ensure clearance at the stern. Its diameter should be less than the diameter of the motor and a 3 blade brass prop would work well. I'm sure the Como with a gear box would work but I suspect at greater cost and much heavier on the current drawn. The propshaft will need supporting at the engine end possibly with a block of wood secured to the floor/keel.
Our TIDs use 555's and can run all afternoon on 6v 7Ahr sla's. NiMhs would work just as well. You will require quite a bit of ballast so the SLA works well for that purpose.
dave976

There are always alternatives. I'm not familiar with the specs of your kit, the LOA for example. Everyone I sail with recommends brushless & LiPOs but I am still in the NiMH world with brushed for the most part. & I'm not much for shelf-looking-pretty models...so welcome to the water!!

In North America circa 2002 use of cordless drill power train was common in larger RC aircraft as the belt reduction cud swing a large prop. The nicad drill's battery gave a 3 to 5min flight with those brushed mtrs

using a motor of unknown specification may have its problems so I would be wary of it. By all means give it a try (I would) but also, be prepared for the unexpected. Don't be disappointed if it doesn't work out 😉

Hi marky
It should suffice but may be quite heavy on current. That said with a large SLA for ballast it will probably last as long as you want to sail on any day.
dave976

Good evening Marky, I have a a large tug running on a 540 motor using a 12v 7ah sla battery with no issues, gives about 90 minutes running on full power while towing or up to 2.5 hours running solo.
As the 550 is much more efficient motor it should be fine.( it's the larger tug)
Cheers Colin.

thanks for the tip about Technobots and also MFACOMO looks to be a good source for drive train items

Marky I forgot to mention it runs through a 3 to 1 reduction gearbox. And has a 65mm 4 blade brass prop.
Hope you find this helpful.
Cheers Colin.

MFA Como Drills
😎

https://www.mfacomodrills.com/

https://www.mfacomodrills.com/gearboxes/gearboxes.html

https://www.mfacomodrills.com/pdfs/belts%20&%20pulleys.pdf

https://www.mfacomodrills.com/price_lists.html

Forgot to add these pictures.
Cheers Colin.

Another spanner in the works???
If you choose to use a gearbox you won't have to cut into the keel as the output shaft would be at the bottom of the gearbox.
Cheers Colin.

Marky, the 550 you have is a more durable motor as its a 5 pole motor whereas the 540 is a 3 pole.
When using low throttle control the 550 will run smoother and longer with 12v.
Cheers Colin.

Colin , my brothers mate has a Como MFA 540 low revving brushed motor 6-12 volts 6000 revs at 12v is this motor a better bet ?
Cheers Marky👍

Marky, this might help you decide.
The chart shows available combinations. The top one on the list is in the tug pictures 2/3/4 running on a 12v 7ah sla battery with a 60mm 3 blade brass prop. That gives a run time of between 2 and 4 hours. Total running weight is 8.85 kilos .
The last 2 pics are of a fishing boat running a 540 motor direct drive to 40mm 4 blade prop. Using 2x 12v 4.5ah sla's gives a run time of about 1.5 to 2 hours. Running weight is 6.7 kilos.
Hope this helps, cheers Colin.

Good evening Colin and Dave, thanks for that ,having only built static before it's a bit of a learning curve for me .
I was going to join the model boat club in Edinburgh but at the moment for medical reasons I'm very much confined to the house and shed ,if the wife had her way it would permanently be the shed 😂.
Cheers Marky 🙄

Hi Marky
I agree with Colin. He used a 3:1 gearbox but a higher ratio would give more Tork. That motor will not give a direct drive to the 4 bladed prop so you will need to source a reduction unit. Technobots do suitable pulleys and belts. Positioning the motor should allow you to have easy access at all times to allow for servicing so is partly governed by the hatch (opening) in the deck. Most of my tugs have 12" or similar propshafts.
Dave976

https://www.technobotsonline.com/t2.5x6mm-timing-pulleys.html

Good evening Marky, that's a 60mm prop on the drawing but if you are going direct drive I'd reduce to 50 if gearing then its fine either way it's your model, the big prop will draw more current.
Left or right handed on a single prop doesn't matter.
In my opinion the motor between bulk heads 5 and 6 with a propshaft of about 12ins is right. But again that's only my opinion, it's your model and you should do it to feel right to you.
If you decide to go through a reduction gearbox, 4 or 5 to 1 would give loads of pulling power with a lower battery drain.
Cheers Colin.