Matching outboard to tinny

Hi All,

I was wondering if anyone could shed some light on how to determine the maximum size outboard that a tinny can handle, if it is too old to have a compliance plate.

Just from experience I have a rough idea of what suits what, e.g. "that's a touch big!" or "that's way too small for that boat."

Is there any hard and fast rule with regards to legality of outboard size on older boats, or is it just a common sense and weight thing?

I guess what I'm asking is how do they determine the max. size that's written on the compliance plate?

Cheers

Dane


Deckie's picture

Posts: 1296

Date Joined: 03/04/09

Not sure.

Wed, 2016-11-23 14:30

Not sure how they do the calculations for motor - hull.
But mine is a 4.2m Savage with a 30Hp 2 stroke Jonno on the back.
Maybe get a few opinions and decide what combination is close to yours & what will suit you best.
Good luck.

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Cheers & Stay safe

Oldbull's picture

Posts: 179

Date Joined: 21/09/15

not official but

Wed, 2016-11-23 15:31

 I have had a 4.2 brooker with a 40hp 2 stroke and that was overpowered and too heavy.  Went to a 25hp yammy which really suited it but could have gone with a 30hp 2 stroke.  A solid 3.6 tinny would be around 12-20hp and a cartopper lightweight 3.3m likely to be anything from a 4-8.  I had an 8hp on a 3.3 cartopper but it needed some weight in the front of the dinghy cause the motor, fuel tank and 90kg of me on the back was a pig.  

Dale's picture

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Date Joined: 13/09/05

Wed, 2016-11-23 17:18

 I have a new 30hp CV yammy on a 4.1m Stacer hull that's a 1997 vintage. I used to have a 40hp Johnno on my last dinghy which was a 4.2 Stacer. Both were/are sweet set ups.

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"Just because you are a Character, Doesn't mean you have Character."

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Daneox's picture

Posts: 68

Date Joined: 07/11/10

Thanks

Wed, 2016-11-23 17:08

Thanks for the examples fellas.  I've inherited my old man's 13 ft tinny which has an old 8.5hp Evinrude on the back, but I've been given a 15hp Mercury by a mate.

I wasn't sure if the 15hp would be too much as the hull is quite shallow, which got me curious as to the actual rules behind it all.

I suppose it can't hurt to put the two together and see how they run!

Dale's picture

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Date Joined: 13/09/05

Wed, 2016-11-23 17:17

 That will work fine mate

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"Just because you are a Character, Doesn't mean you have Character."

Mr Wolf

 

 

Oldbull's picture

Posts: 179

Date Joined: 21/09/15

yep

Wed, 2016-11-23 18:44

 A 13ft with a 15 hp will be sweet..  You can lug a 15 around easy enough but much bigger becomes heavy to  carry around and take on and off the transom.

Darren253's picture

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Date Joined: 23/07/16

I had a 3.7m Stacer with a

Thu, 2016-11-24 10:01

I had a 3.7m Stacer with a 15HP 4stroke Suzuki on. Went like the clappers even loaded 3 up! At monkey mia on a mirror day I clocked it on the GPS at 46.5K/hr solo which is pretty fast only inches above the waterline!

Daneox's picture

Posts: 68

Date Joined: 07/11/10

Sweet

Thu, 2016-11-24 12:50

46.5km/h, that is quick!

Thanks again lads, appreciate the input 

Posts: 23

Date Joined: 14/11/16

Hi there, I have a 2016

Fri, 2016-11-25 04:58

Hi there,
 
I have a 2016 Qunitrex F390 ( new Fighter Hull ) with a Suzuki DF20A and with two blokes a gear estimated 215kgs of payload - 18.8kn WOT on reasonbly smooth water with a
91/4 x 9inch prop - 23kn WOT on absolute glass - with a 91/4 x 11 inch prop - The 9 inch prop is far better in the rougher water although with a hydrofoil tends to cavitate easily if you pour the RPM on too quick. I may try a 10 inch blade just to satisfy my curosity. The suzuki DF20A is soooo quiet and has good torque - drinks next to nothing on WOT and i can lift it on and off no problem - its pull start and electric - therefore runs a charge circuit for the EFI and is ample to charge a Gel Cel to run a plotter/sounder.