Thread: Power boat for the young fulla

I'm not sure how old I'll go out to the shed soon an run the number. Its quite old mid-late 70's I think. I'll put a pick up on the weekend when I get it out, its in quite tidy condition for its ages last owner reckons she runs like a dream.

Short shaft I think but no doubt you guys will be able to tell when I put a pic up.

What are the advantages/disadvantages of short/long shaft?

if you build a deep vee hull it will take more power to plan and give you more grip in the turns 25-30 degree should be sweet and about 4m loa should suit the 15hp nicely have a look at pelin plans they may have something to suit Pelin Boat Plans - Build Your Own Boat

Think regards the shaft length the longer the shaft the deeper the V but not positive on that.
Think Mariner ,Yamaha are rated at prop ,don't know about all modern motors.
From memory the prop rated motors like adding another 5 hp .?

Originally Posted by Chris

Think regards the shaft length the longer the shaft the deeper the V but not positive on that.
Think Mariner ,Yamaha are rated at prop ,don't know about all modern motors.
From memory the prop rated motors like adding another 5 hp .?

Johnson/evinrude changed from flywheel rating to prop rating around 1988 j140hp at the flywheel now equals 115 shaft hp. the trim plate at the top of the skeg needs to be parallel to the keel at half trim the height of the transom will be determinded by the length of the leg (mounting bracket down to trim plate) the trim plate may only need to be 10-20mm lower then the keel. if set to high you will lose trim and also you will ventilate the prop losing power and posablly depriving the leg of water and running your cooling impeller dry.

Originally Posted by mucko

Johnson/evinrude changed from flywheel rating to prop rating around 1988 j140hp at the flywheel now equals 115 shaft hp. the trim plate at the top of the skeg needs to be parallel to the keel at half trim the height of the transom will be determinded by the length of the leg (mounting bracket down to trim plate) the trim plate may only need to be 10-20mm lower then the keel. if set to high you will lose trim and also you will ventilate the prop losing power and posablly depriving the leg of water and running your cooling impeller dry.

Your a legend Mucko, I'll be able to design the whole ass end of the boat off 1 paragraph.

Only rule with boats is the same as cars HORSEPOWER ----------- lots and lots or you will be disappointed long term

Listed outboard on TM. Yamaha 15H 2 stroke short shaft | Trade Me

Since I'm such a nice guy 10% discount off final bid for forum members

Originally Posted by big_foot

Listed outboard on TM. Yamaha 15H 2 stroke short shaft | Trade Me

Since I'm such a nice guy 10% discount off final bid for forum members

Is that not F.N.R selector on the side of the engine in pic 1

looks like someone has spent shitloads on it.

Originally Posted by mucko

Is that not F.N.R selector on the side of the engine in pic 1

looks like someone has spent shitloads on it.

Lucky I have the wisdom of you guys behind me

Yea shes tidy alright aye almost vintage

Cheers mucko

Done abit of fishing in a 12ft marco with a 9.9 on it, it had no problem getting 2 adults on the plane.

Originally Posted by big_foot

Lucky I have the wisdom of you guys behind me

Yea shes tidy alright aye almost vintage

Cheers mucko

just thinking about it at milking thats a 70's 15hp that will = about 10 shaft hp in a post 1990 outboard

So I've scored a motor for the boat, 4hp evinrude, it was the smaller end of the power range I had in mind it just means I'll be able to get the boy in it at a younger age and always have the option of a re-power.

I've been collecting old pairs of chainsaw chaps from my workmates, why you ask? each leg has 6 layers of kevlar cloth, this shit is tough as nails and seems to be an awsum substitute for fiber glass mat. Each pair of chaps has about equivalant to $30 worth of cloth of I was to buy from Bunnings, I bought 3 pair home tonight and already got a few others. Some people call me cheap, I prefer "resourceful".

However Ive encountered a couple of issues, firstly I need to get all of the oil residue out, I was thinking soaking in a bucket of degreaser?

Secondly, cutting the shit is insane. I'm using a Tajima utility knife to cut the kevlar out of the legs and I have to break the tip off about every 500-700mm. Any suggestions? (how many smart asses are gunna suggest a chainsaw???)

Grinder with cutting disc?

Originally Posted by Toby

Grinder with cutting disc?

Like a blade cutting disc? one of those steel cutting discs would pick up the thread an leave me in an almighty tangle

Yeah, second thoughts haha.