Tender Fun

[Norlandia33]

Hi, guess here is the place to ask.
I bought a 3m rib as a tender at the end of last season and my little Honda 2hp is quite happy to push it along. But for the occasional bit of fun i would like a bit more speed (not something a raggie is not used to !) . The rib has a max outboard size of 10hp.
Q. Is this a bit much ?And what would happen if i did exceed the max size?
Thanks in advance


<hr width=100% size=1>Squidge

 

[lanason]

If it is rated at 10hp then this of course will be fine - and for 3m rib should be rather quick - I guess around 20knts with one person up.

So if you put a bigger engine on the risks are:-
1) You put too much stress on the transom and cause damage
2) The extra weight affects the handling and control.
3) The heavier engine is difficult to lift on and off - in fact much more than 5hp is not easy (esp if trying to luift onto the dingy from the boat is moving seas) - bet you dont have a bathing platform /forums/images/icons/smile.gif
4) Extra power may take the speed above the design speed - making it very dangerous in anything but dead calm seas. Trust me - you'll be bound to push it Flat Out just to see what it does.

if you have a Rag and Stick then you could tow it with engine on - but it will put extra stress on tow rings.


<hr width=100% size=1>Adrian - <A target="_blank" HREF=http://www.arweb.co.uk/argallery/kelisha>More Pics of Kelisha</A> /forums/images/icons/smile.gif

 

[Moose]

I have a 3.11 RIB with a 10hp engine. It will touch 22kt's with me in it. No1 Moose can get nearly 25kt's /forums/images/icons/crazy.gif
I have the RIB on davits but on the occasions that I need to take the engine off it is a 2 person job as it weighs nearly 40kg. I guess this is going to be your main problem. Plus it is massive if you are going to store the o/b in a locker.
Expect the RIB and engine to weigh somewhere in the region of 100kg, perhaps beef up your towing rings if this is the idea.

<hr width=100% size=1>My Moose is having a rest, he has done enough walking for the year.

 

[hlb]

You back from Basera then??

<hr width=100% size=1> <font color=blue>No one can force me to come here.<font color=red> I'm a volunteer!!.<font color=blue>

Haydn

 

[Moose]

Yes, very nice down there (see restaurant forum)

<hr width=100% size=1>My Moose is having a rest, he has done enough walking for the year.

 

[tcm]

Re: Wimp

If rated at 10 it'll be fine at 15. We had tender rated 8 whammed on a 15, fine so long as u don't try big waves. Use a razor blade to cut the "1" off and make it look sensible. I borrowed an o/b first to have a go, try lifting etc

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[lanason]

Re: Wimp

He's a raggie for christ sake - not a hardened speed merchant.

Perosnally I'd put twin 40hp's on the back /forums/images/icons/smile.gif but I live dangerously /forums/images/icons/laugh.gif

<hr width=100% size=1>Adrian - <A target="_blank" HREF=http://www.arweb.co.uk/argallery/kelisha>More Pics of Kelisha</A> /forums/images/icons/smile.gif

 

[whisper]

Re: Wimp

Gordon Bennett a 15 is going to be heavy, just to tilt let alone lift on and off.
Oh and by the way, if you have an accident you will not be insured. Lunatic /forums/images/icons/smile.gif

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[Norlandia33]

Thanks for all the good advise, the insurance aspect is something i had not considered. 20+Kn in a 3m rib sounds scary but gotta be tried.
Regards


<hr width=100% size=1>Squidge

 

[Questor]

I think you'll find most 10hp & 15hp outboards from the same manufacturer are exactly the same weight, so if it'll take a 10hp, it'll take a 15hp. However, most 10/15hp outboards weigh approx 40 kgs, so will be hellish difficult getting on / off in anything but dead calm sea. Should go like stink, but always tie a line to it when taking on / off, as one day you will drop it. Probably best stick to an 8hp.

R

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[Jim44]

Sounds like you wish you had power boat! do you ?

Just think, you could get 700HP, how much fun would that be

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[oldharry]

<...If it will take a 10hp, it'll take a 15hp.>

No it wont. The extra power and torque from 15hp well exceeds the design limits of the boat, and apart from risking structural damage, could be very dodgy to handle on acceleration and in turns - possibly even flipping over backwards on acceleration.

For further confirmation see your insurance company, who will most definitely NOT provide cover in the event of an accident or claim.


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[tcm]

This just isn't true. There are no bespectacled engineers carefully calulating the exact strength of the transom, and the loads at various speeds. The physical strength in all such complex fabrications is almost impossible to evaluate with an degree of accuracy and hence found largely from trial and error, and a healthy dose of safety margin, plus some more safety margin for the production variations, and commercial/warranty reasons. It is simply not true that a 15hp engine will rip a boat apart, whereas a 10 hp never will, cos there's a little plaque saying so. Lots of 15 hp engine are lighter than 10hp. The extra acceleration is minor, not huge. We aren't talking aboiut multiplying the power by a factor of ten.

I don't disagree with the insurance aspects.



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