"overpowering" the tender

O

ontheplane

Well-Known Member
Joined
20 Mar 2004
Messages
2,105
Location
Bristol UK
Visit site
\"overpowering\" the tender

Further to a previous post, We use a tender which is rated up to a 10hp engine + 4 people.

I am looking to change the 8HP longshaft engine for a 9.9 shortshaft, but would it cause a massive problem to go to a 15hp?

I had a tender before that was rated to 4hp and I had a 6 on it without issue - but would this be a step too far?

Have others "overengined" their tenders, and have there been any problems?
 
Re: \"overpowering\" the tender

presumably your outboard has a throttle? think weight is the issue, not power /forums/images/graemlins/smile.gif
 
Re: \"overpowering\" the tender

Oh absolutely - the throttle has two positions, tickover and FULL yehhhh

Seriously, the weight of almost all the 15hp's seem the same as the 9.9's - most seem based on the same block.

And yes, I'm not daft, I wouldn't try full lock full power turns if I'd overpowered, only flat out when on glassy smooth water in a straight line.

Also - with a 2.7m airdeck tender, and a 15hp (perhaps with a slightly finer pitch prop), what's the chances of pulling a wakeboarder or am I dreaming?
 
Re: \"overpowering\" the tender

The ratings on most tenders are ar$e covering exercises.

Don't expect to claim on the insurance if it does explode at full chat. Other than that, go for it!

I broke almost all the slats on my slatted floor QS240 last season by hitting waves at planing speeds. Had to replace them, but worth every penny in my book /forums/images/graemlins/smile.gif
 
Re: \"overpowering\" the tender

We used to have a Humber 10+ with a Mariner 9.9 would pull my sister up on water skis also had a ski disco great fun, the trick was to lay flat till boat was just getting on the plane then pull yourself up onto the disc.

Chill
 
Re: \"overpowering\" the tender

[ QUOTE ]
Have others "overengined" their tenders, and have there been any problems?

[/ QUOTE ]

Where's Hurricane when you need him? /forums/images/graemlins/grin.gif /forums/images/graemlins/grin.gif

Cheers
Jimmy
 
Re: \"overpowering\" the tender

[ QUOTE ]
Also - with a 2.7m airdeck tender, and a 15hp (perhaps with a slightly finer pitch prop), what's the chances of pulling a wakeboarder or am I dreaming?

[/ QUOTE ]

I had my Merc 10 XR on a Quicksilver 270 air deck last year and it was fine. Would probably pull a youngster out on a wake board too. 15Hp may be ok but you'd need to make sure the person driving had some sense. /forums/images/graemlins/wink.gif
 
Re: \"overpowering\" the tender

Weight of motor can be an issue, Tohatsu used to do alightweight 9.9 have a look around. I always thought the problem is having a stiff enough floor so it does not bend and being able to get your weight well forward to get on the plane.

A word of caution its one thing you using it but are there any 8 or 10 year old 'ontheplanes' who will be using it who are a lot less fearfull and about a third of your weight? If so they will literally fly.
 
Re: \"overpowering\" the tender

[ QUOTE ]

Where's Hurricane when you need him?

[/ QUOTE ]

I was keeping my head down on this thread but now that you ask.
Definately overpowering is OK

When I picked up my tender, I was very concerned that I'd over cooked things - I even PM'd the likes of RogerRat to see what they thought - I even suggested returning it before it had been used.

Then I put it on the water and actually ran it - WOW
That was last summer - every time anyone uses it, it brings a big smile to their face.

For those who dont know, its a 3.4m Walker Bay Genesis with a console - oh yes and a 40HP Yamaha.
It flies.

Initially, you would think that it is a bit stern heavy when there is just one of you but when you get used to it, its great. Just a little prod on the throttle for about 3 secs will bring it onto the plane and it just stays there.

Even with 4 large adults on board she planes efortlessyy.

Here's a video clip with two large adults on and a skier - I was driving and the throttle was only about two thirds open.

http://www.youtube.com/watch?v=N2X5gLFr1y0

Video by Rickp
 
Re: \"overpowering\" the tender

[ QUOTE ]
, the weight of almost all the 15hp's seem the same as the 9.9's - most seem based on the same block.


[/ QUOTE ]

Correct, and there is a very good reason for this. Ever wondered why it's a 9.9, not a 10hp, when all the other ratings are round numbers?

It's because in certain countries (France I think) you need a licence for a boat with 10hp or above. Hence the big market for 9.9hp engines.

And what most manufacturers do is simply de-tune their 15hp offering to 9.9hp.

So invariably most 9.9hp engines on the market are really 15hp's, but turned down, hence the weight being the same.
 
Re: \"overpowering\" the tender

I must confess I'd never thought about it!

Makes sense now you mention it.

Therefore, if I can find a s/shaft 9.9, what work is required to turn it into a 15 then, is it as easy as buying some new Carb jets or is it not that simple?!?
 
Re: \"overpowering\" the tender

That was the case, but not so much anymore. Certainly Mariner/Mercury, and Yamaha offer 9.9's based on the same block as their 8's. The 9.9's are typically less than 40 kgs (mariner is 37 from Memory), whereas the 15's are 45-50 kgs.

I think weight is more the issue than power on a 2.7m, so a lightweight 9.9 may be more suitable.
 
Re: \"overpowering\" the tender

I'm looking at early 90's motors though not the brand new stuff. I want to get it under 35kgs for a 15hp if I can... Yamaha and Mercury both seem to do one.
 
Re: \"overpowering\" the tender

The Mariner will prob be the same as the merc or yamaha at that age from what I remember so worth looking at that.

Put a 25hp mec on my Zodiac 2.8 (slatted floor) once...mixed and indeed interesting results.

You will just need a good solid floor and keel (ply or inflatable) otherwise it just flexes too much. sorry cant remember if you said it was a rib or not.
 
Re: \"overpowering\" the tender

We had an 8hp ona 270 Airdeck and SWMBO managed to wakeboard behind it once. Much better off the present Johnson 15hp ona 3m RIB, though. The Johnson is the same block as the 10hp unit and weighs about 35kg from memory (the 4 stroke one is 44kg).
 
You must log in or register to reply here.

Other threads that may be of interest

N
Volvo Penta Alarm Module/Alternator Issues
Replies
1
Views
198
superheat6k
superheat6k

Share this page

Top