Outboard for 22foot yacht

Hi there,
i recently purchased a Tasman 22 fixed keel yacht. It's fiberglass construction.

its. 1973 model and originally had an inboard diesel but previous owner has removed.
it has an outboard bracket on the back.
I was wondering what ideal power would be. I was thinking a 15, but a good friend (who also happens to now be a master skipper) told me they had a 15 on a trailer sailor a few years ago and it struggled to get back inside the bar on an outgoing tide (Mooloolaba).

...and someone else told me if I'm crossing the Noosa bar (haha the boat is currently in Noosa River) I may need a 20 or 25 to stay in front of the wave when coming back in.

But a 25 seems quite heavy and wondering if bracket is designed for such weight?

Any advice would be appreciated
thanks
paul

You are only going to push that boat at it's hull speed which I would suggest is about 5-6knots so a 9.9hp should be heaps I would of thought

Tasman 22. What a fine little yacht. 6 hp two stroke is ample. Do you still have the shaft/ prop etc?

3tonne Top Hat 25.

Have a 5hp 2strokeTohatsu short shaft (great for lake etc light to lift onto transom).

Got a 8hp 2stroke Tohatsu long shaft (good for ocean and pushes boat at hullspeed at bout 1/2 to 3/4 throttle depending on conditions). Heavier but easy to move to transom.

Outboards will cavitate in short chop/bar crossing but go fine and cost effective reliable propulsion

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Yara said..
15hp- you got to be kidding. Your friend must be a power boat owner. More than 6hp on a 22ft yacht and you are just climbing your bow wave. I have an extra long shaft 6hp Tohatsu Sailpro,and it is way overpower for my heavy 18ft- 6" boat. However, I think that would be fine for your boat. An extra long shaft and sail prop is more important than shear grunt, and you dont want too much weight hanging off the stern, either. Doubt the bracket was "designed" if it was a retro-fit.
You need to watch the tide on a bar crossing with a yacht, and a strong outgoing tide is not the right time to be doing it.

Thanks :-)
yes I would need the top of incoming tide ideally? It has a 1.3m draft and Noosa bar is not exactly renowned for its 'deep' channel.

Im now looking for something smaller HP

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FolkboatM26 said..
+1 on the sail pro 6hp. 25kg, 1.5lph. Does ok on my 2 tonne folkboat, would ideally have an 8 but factoring in light weight and limited fuel requirements, compromise was made. No blue smoke or oil mixing a bonus.

Yes the 4 stroke sounds like a better option, and I was sourcing a long shaft...but will also try and find a sail prop

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Tasman22 said..

dism said..
3tonne Top Hat 25.

Have a 5hp 2strokeTohatsu short shaft (great for lake etc light to lift onto transom).

Got a 8hp 2stroke Tohatsu long shaft (good for ocean and pushes boat at hullspeed at bout 1/2 to 3/4 throttle depending on conditions). Heavier but easy to move to transom.

Outboards will cavitate in short chop/bar crossing but go fine and cost effective reliable propulsion

Thanks.
yes am looking for a 8 - 9.9 hp
is hull speed similar principle to 'on the plane' optimal speed and fuel economy, minimal drag?
maybe I just get on the googles hey!

Hull speed is the opposite of a planning hull. Displacement boats have a hull speed someone better educated than I can explain it better but basically hull speed us where a planning hull would get up on the plane. The boat creates it's iwn wave causing the arse to dig in and all you do is create a huge wake and use lots of fuel. There is a formula used someone will post it I'm sure.
I have always been a fan of deferring to a larger size motor than needed when weight is not an issue (non racing ) . When crossing a bar while you will still only get hull speed a bigger motor will get you there faster if needed. Also if you are caught out in 40 knts you want to be able to punch into it.
Back in my racing days plenty of times l have been in boat's where the small outboard would not push us in 30 knts.
Also try emailing Kay Cottee I am sure if it was nhers she would also have some nostalgia as most of us di to our old boats.

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Tasman22 said..

dism said..
3tonne Top Hat 25.

Have a 5hp 2strokeTohatsu short shaft (great for lake etc light to lift onto transom).

Got a 8hp 2stroke Tohatsu long shaft (good for ocean and pushes boat at hullspeed at bout 1/2 to 3/4 throttle depending on conditions). Heavier but easy to move to transom.

Outboards will cavitate in short chop/bar crossing but go fine and cost effective reliable propulsion

Thanks.
yes am looking for a 8 - 9.9 hp
is hull speed similar principle to 'on the plane' optimal speed and fuel economy, minimal drag?
maybe I just get on the googles hey!

Hull speed in a normal yacht (yours but not Americas Cup foiling ones) is basically approx square root of hull length in feet.

So your boat (non-plaining ie drags thru water) cant go over say 6kn (regardless of engine hp), unlike a speedboat (plaining ie skimming along) etc which can just add infinite hp engine to go faster

Next is the holy grail of foiling and all bets are off in hp/knots of wind to boat speed