8 to 15hp

[tuskar]

Hi all.
Have an 8hp 2 stroke (mariner 1980s) on my Achilles 12ft sib a bit feeble and just about planes 1 man 80kg at 15mph, with two people it ploughs at 7MPH .
Question is would upgrading to a 15hp Johnson 2 stroke 2003 do the trick for say 2 or 3 people.
Thanks

[paddlers]

What's it rated for? I usually work on slapping the most horses on provided you can lift it ?

[tuskar]

Achilles boat is rated 20 hp. But this 15 is a very nice engine, would 5hp less make it very underpowered
Should i hang out for a 20hp

[John Kennett]

It should go very nicely with a 15hp with 2 or 3 on board. If you load it to the gunwhales though it will struggle.

[tuskar]

hhmmm
I do like reasonable performance especially a couple miles off coast St Georges channel can run 8 knots

[paddlers]

I can only give you my own experience with my Honwave 3.5 AE . I have a 2005 Mercury 15hp 2 stroke & a new Tohatsu 20 hp 4 stroke.
The Tohatsu gets it onto the plane quickly with five of us on and stays there at 50% throttle but the 15 we have just gets us out and has to work hard. The mercury has a stainless prop, Tohatsu standard ( no idea of pitch).
The Tohatsu is HEAVY compared to the Mercury but does use a lot less fuel.

Horses for courses really. We tend to be away for two weeks so putting the Tohatsu on/off isn't an issue but the Mercury's a lot handier for a day out especially if you have to transport it.

[Big Al C]

A 15hp 2s will do the job 2/3 people and weigh in around 36-40kg.
Were as 20hp 2s will also do the job but you are looking at 48-53kg as the 20 is usually a detuned 25hp.

I run a merc 15 and don't have any trouble moving it around 37kg, but also use a 30 Johnson which is the same block from the 20 to the 35 and weighs in at 53kg ish. So pick and choose which engine to use depending on were I launch from.

Both push our 3.8 along well just the 30 gets there quicker with a bigger smile.

[tuskar]

OK guys Im getting the picture now , so some 20s are as heavy as some 30s ,sounds daft but I understand reasons how so.
Starting to lean towards the 15hp as dont like lugging weight about and its an old transom .
Reason i wish to upgrade engine is last September we got caught 3 miles out very strong headwinds got up took ages to get in and ran on petrol fumes for last few minutes.

[stevo]

i run a 15hp yamaha 2stroke on a avon 400s a fairly heavy sib it gets the avon on the plane no probs .

[tony t]

I run a 15hp 4stroke Suzuki on a 3.8 tohatsu
last weekend on Ullswater we had 21knts with 2 15stone men up and 26knts with one


Sent from my iPhone using RIB Net

[beerbelly]

Originally Posted by tony t

I run a 15hp 4stroke Suzuki on a 3.8 tohatsu
last weekend on Ullswater we had 21knts with 2 15stone men up and 26knts with one


Sent from my iPhone using RIB Net

jeez im going to change to a four stroke 26 knts is 30 mph in a 3.8 sib that's quick . best iv had out of my 3.2 airdeck with 15 2 stroke is 22mph that's only 19 knts or so

[Biggy]

Weird,
I've had 17knts out of my 1978 2stroke 9hp on a 3.8 honwave, and that was 2 up. 😎

[philpot]

I know this is 4 stroke but Honda 10, 15 and 20hp are all the same weight which if my memory serves me correctly is about 47kgs. It always pays to check manufacturers listed weights and even with 2 stroke engines, you can usually find the data on the internet.

Phil

[beerbelly]

Originally Posted by Biggy

Weird,
I've had 17knts out of my 1978 2stroke 9hp on a 3.8 honwave, and that was 2 up. ��

that doesn't surprise me me and a pal were racing back to shore at clachtol last year (my signature pic was taken when we got to the shore) fairly flattish water and we were neck and neck he had a 9.9hp on a 3.0 sib against my 15hp 3.2 meter sib both had virtualy the same top end I might have been pulling away by 1 or 2 mph at the most nothing in it .holeshot though I leave him for dead. the point is ,there is a point where you start getting ever smaller returns for increasing power

[Biggy]

I've got a 15hp suzuki 4 stroke now aswell, dying to get out on the water and see what difference it makes.
Roll on holiday time 😜

[beerbelly]

Originally Posted by Biggy

I've got a 15hp suzuki 4 stroke now aswell, dying to get out on the water and see what difference it makes.
Roll on holiday time ��

oh yes roll on clachtol 2015 and luing 2015 cant wait

[tuskar]

Bought the johnson 15hp 2003 2S. Cant wait to get out and try it , I am a little annoyed as weather is very stormy and only 5c .