Recommended Engine Size for 3.5m Inflatable?

[Don Logan]

Thanks for the advice. No, i'll admit that i haven't tried to lift an outboard of any kind, ever in my life, let alone a 20hp four stroke...

I do realise that 50+ kgs of awkward weight is blo0dy heavy though, but being as all of the 15's that i've looked at seem to weigh the same as the 20's i've seen, it would mean that if i wanted to go for something of a more manageable weight then i'd be looking at a 10hp, which seems to be underpowered for something of this size with what i want to do with it. Would that not be the case?

[Xk59D]

Yamaha - 15hp 2 stroke s/s Boat Engines for sale in Hampshire, South East | Boats and Outboards

noticed this for sale, meant to be 36kg...........nothing to do with me but may be worth a looksy.

cheers

[Glow]

Have you seen the Tohatsu 18hp 2 stroke on eBay?

[Don Logan]

Thanks Xk59D and Glow,

I had seen the 18hp 2 stroke on eBay but it's in Bradford and is an 11 hr round trip away. I know i could have it couriered, but then wouldn't be able to see it first. I know it's the engine to go for in terms of power to weight, but not having much knowledge on outboards I wouldn't know if it's well priced or not. Any opinions? Also, i see it's electric start. Do electric start engines have a pull start too in case of malfunction or flat battery?

Regarding the Yamaha 15 2t advert- That one would be good if only it were a 20hp... Is it likely to measure up to a four stroke 20hp in terms of power? I know that 2 strokes have snappier acceleration, etc. but would it still move a 3.5m sib with 3 adults and stuff on board fairly quickly?

Thanks again for the advice..

[Xk59D]

Don,

i have no direct experience of this on your size of boat so i can't comment from personal experience. so take the following as generic advice on the subject.

i would max out the HP rating if you think you can lift the weight onto the boat...........50kg plus is a lot of outboard to carry about, especially if you launch far from the car. ofcourse you can make a trolley/wheels etc to make life easier if you wish to do that and can get it in your car.

i would think the 15 yam would be fine at getting up on the plane and very comparable to a 20hp 4 stroke.

once you are on the plane then the 4 stroke benefits would be show more in that they are quiet and fuel efficient. that said, it is only 15-20hp we are talking about here so none of them will drink fuel at an alarming rate and i personally wouldn't give a hoot about that unless you are doing LOTS of hours, like many hundreds per year. it may be a concern to you though.

another factor is are you going to carry an aux engine? if so you may hit the transom limit quickly, you may even max it out with the 20hp 4 stroke? check your makers plate for info on that and get a tape measure you make sure you have room before you spend a penny on anything........the 15hp 2 stroke leaves enough leeway to get a 2-3hp outboard should you wish,weight wise anyway if not space wise.

although not a honwave, this may give you some idea-

https://www.youtube.com/watch?v=e3Oh0CxZxoo

HTH

cheers

[kaman]

Originally Posted by blootac

Be careful getting it in and out of the boot.
This time last year I slipped three discs in my neck getting a 9.9 2 stroke out of my car. in November I was still getting shocks down my right arm and had only just got feeling back in the right side of the face.

Plenty of people do store them in the car, just be careful and do it slowly. It's not as if I'm particularly old, I'm only 28. Rushing can end a holiday very quickly if you hurt yourself.

I've since got a trailer as it just makes life so much easier and means I can use the boat by myself and I don't have to pick anything up.

I'll second Blootac on this .
I prolapsed my C5/C6 disc in my right neck wrestling a Tohatsu 20hp 4 stroke out of my car boot and into my Honwave 3.5ae.
Tooth ache like pains in arm, eye socket and face followed!
8 months off work to boot!
Transom wheels are a must for this Sib.
To be honest a trailer is the only way to manage and fully enjoy this Sib with a 50kg + engine.

[dave3235]

Originally Posted by Max...

I'd disagree - a 3.4 to 3.8 is fine with a family, two adults and two teens let alone toddlers. Go to a 4m and it's a lot more weight especially with the solid floor - and the airfloor 4m Honwave is well known as being floppy as a floppy thing.

Are you sure!

[blootac]

Originally Posted by kaman

I'll second Blootac on this .
I prolapsed my C5/C6 disc in my right neck wrestling a Tohatsu 20hp 4 stroke out of my car boot and into my Honwave 3.5ae.
Tooth ache like pains in arm, eye socket and face followed!
8 months off work to boot!
Transom wheels are a must for this Sib.
To be honest a trailer is the only way to manage and fully enjoy this Sib with a 50kg + engine.

Yeah. I've just towed mine 740 miles last weekend and it was SO much easier than faffing with putting everything on the roof and in the boot!

[blootac]

Originally Posted by Don Logan

Regarding the Yamaha 15 2t advert- That one would be good if only it were a 20hp... Is it likely to measure up to a four stroke 20hp in terms of power? I know that 2 strokes have snappier acceleration, etc. but would it still move a 3.5m sib with 3 adults and stuff on board fairly quickly?

Thanks again for the advice..

(I might have said earlier in the thread I can't remember)
we had a 9.9 with a 3.4 heavy avon rover with 2 large adults and 2 children, later upgrading to a 15 2stroke for the now 2 teenagers + 2 large adults. it planed with both but the 15 had just that extra power to make it easier to plane.

I'd say that the 15 will almost certainly make you plane. My 380 planes more than happily with 2 adults and a 9.9 4 stroke. Haven't yet tried it with 3 but I'm expecting it to. I'm not expecting mine to be quick but it's fine for what I need.

[paddlers]

I haven't read the whole thread but I bought a new Honwave 3.5 AE last year and put a Tohatsu 20 4 stroke on it & wheels.

Planes with this lot aboard (I'm 18 + stone) easily. Nice stable outfit, economical and well made. The engine is easier for two people but if you pop a pair of hernia briefs on it's not impossible on your own. The 15 hp Mercury 2 stroke I had was lighter but didn't have the grunt of the Tohatsu 20.

[Don Logan]

Thanks all for the advice, I got a Mariner 20 in the end. Boat goes very well, engine isn't too bad on weight- I even managed to lift it into a wheelie bin by myself to flush it so can just about manage it..