What max size outboard for my dinghy

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nyx2k

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my 2.5hp is a little underpowered for the chi harbour when flow is max.

what size outboard do you think would be better, i fancy a 6 but would this be too heavy or too powerful.

the weight issue isnt to bad as i can sit on the transome and its still a few inches below the gunwhales.

if i mounted a bigger engine i could sit further forward to offset the extra weight.

the dinghy is 11ft and very stable and weighs about 150kg
 
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had a similar size tender with a 2.5hp, just changed up to a Yamaha 4 stroke 4hp, its great now, you would be welcome to try it on yours.
 
Single cylinder four strokes weigh about 25kg and go up to 6HP, generally. Two cylinder motors weigh 40 kg or more. So, I'd choose a single cylinder motor up to 6HP.
 
I've got a 10' with a 2.5hp on the back (previously had a 2hp) and one way will always be against the flow - so I nip into the bank and run as shallow as possible - it's only 1/4mile each way so no drama - and that is in Chi Harbour too ...
 
i need to try a 4hp and see if that would be enough.
i realise the boat will never plane but i need to make headway against the full flow.
i was being pulled backwards on saturday as i was leaving eastspit on the way back to itchenor.

i had to use full power and hug the bank to get back.
 
nyx2k said:
i need to try a 4hp and see if that would be enough.
i realise the boat will never plane but i need to make headway against the full flow.
i was being pulled backwards on saturday as i was leaving eastspit on the way back to itchenor.

i had to use full power and hug the bank to get back.
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Displacement max speed approx 4.5 knots. Spring rate likely to be anything up to 4knots. Therefore you stand still! Only way to exceed that is to get a planing hull. There is a trade off between size, weight, hp, cost that suggests you avoid times when the rate is at its greatest. Doubling the power on a displacement boat might push the speed up by a knot. OK if you don't mind the extra weight, cost and fuel consumption.

Actually a Seagull Silver Century is the ideal engine for your boat, or a Plus if heavy laden.
 
looks like i may be better keeping the 2.5 hp then.
or get a planing hull about 12ft and a 15hp 4srtoke then i can still keep it on the chains
 
It is important in Chichester to be aware of what the tide is doing.
It is very strong when a spring tide is ebbing during about 3-5 hours after HW. The flood tide is never as strong.

Just sensible to avoid trying to claw your way back up the harbour against a spring ebb during those few hours .

Generally I'd have said that a 4 hp would be adequate for you needs.

If you do start looking at 4 hp and above be aware there can be some big differences in weight between different makes or even between different versions of similar engines from the same manufacturer.
Johnson and Evinrude made two versions of the 4hp in the 1980s. One weighed only 15kg, the other 23 kg! One is not a lot more than a small Seagull, the other is almost as much as my 6hp that I do not lift and carry these days!
 
i was hoping for a considerable increase in my speed which others have said wont happen.

the boat is pretty heavy so i presume this is only a displacement hull.

my 2.5hp is very reliable and im wary of getting a 4hp of unknown origin so may be better keeping the 2.5hp until i can find a reliable 4-5hp to replace it and keep the 2.5hp as backup
 
You may have seen the Tohatsu, looking for an offer, on the For Sale section? I think that would suit. If you go for a 4/5hp do report back and tell us how you got on.
 
i pm'd about the tohatsu and no reply so he /she must be away.

will be going to chi later again on a falling tide so will stick to the edges
 
My 10'er is a Walkerbay - if just me in it I can sit forward and get up to 5 knots with the 2.5hp - It's just on the verge of planning ...
With passengers I'm back down to 3-4kts
I did run a 6hp for a short while - this was much thirstier than the 2.5 and didn't have a significant impact on speed - I think I managed 6kts - made more noise than speed - may have just been the engine though!
Walkerbay is quite light
 
my dinghy is heavy.
im pretty strong and i cant lift the stern off the floor and have great difficulty turning it over to look at the bottom.
 
nyx2k said:
my dinghy is heavy.
im pretty strong and i cant lift the stern off the floor and have great difficulty turning it over to look at the bottom.
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Er ... you might be better off getting a lighter dinghy then!!
I'm pretty strong too - but SWMBO and I can lift the tender (with engine and light kit) off the floor to put on a trolley. I also turn the boat over (by myself) for storage - although by this time it doesn't have engine or kit in it!

No doubt 6HP will push you faster but you'll still struggle against a full ebb as anything above 4kts will be trying to start to plane..
 
it seems a payoff between stability and extra speed. i can stand up in the dinghy now but maybe not in a different hull shape.
i need to look at some different designs
 
i can just drag the dinghy from the chains into the water at itchenor hard but have no chance of dragging it back up when it's low tide even with 2 strong men so i use the car to drag it back to the chains
 
walkerbay say it weights just 57Kg - it is easy to drag - but only tend to drag on concrete as that's where we launch from.
I can stand in the WB - but it isn't completely stable - if I stand on one side it will fill with water. However, it will take 3 adults with little problem (not at 5 knots though!).
TBH we have been looking at other tenders as we usually need to get 4 adults onboard with baggage - which the WB just won't cope with - it would be nice to have something a little more stable which would allow someone to stand on the side with no chance of capsise without needing to counterbalance as we currently do.
 
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