Need advice regarding engine size

[UKNick]

Looking for advice...

I'm looking at buying a Honwave T35, or T40 - Obviously the T40 is bigger, but at 86kgs, it's heavy.

Will only use it in calm water, or a slow running river, Never out at sea.

I already have a Suzuki DF2.5 outboard which I bought new. It's great as it's very lightweight, but obviously not that powerful. It was absolutely fine for my previous WavEco 300 air mat (3m) dinghy, but that was only 43kgs (So half the weight of a T40).

I don't want to buy another 'air-floor' dinghy as I prefer the stability of the Aluminium floor, so I've ruled out the Honwave T38. Not bothered about time putting ali-floor dinghy together, as once done, will leave it on trailer.

Not the slightest bit interested in going fast, or taking on waves out at sea - just want to 'chug' around, chilling out. Usually just my wife and me, maybe twice a year with grandchildren.

My existing Suzuki is light and easy to move, so don't want to have to buy a bigger/heavier engine.

My question is: Will the 2.5hp outboard allow me to chug around on an 86kg dinghy like the T40 or do I really need a lighter dinghy??

[Fenlander]

Those Honwaves are quite heavy particularly the T40. Of course a 2.5hp will move it in the same way as a 10yr old with a paddle could.... but for me even on the river I like to have a squirt of power available to place a SIB where I want it to go as they will blow about over the top of the water compared to a displacement boat. I've found much less than a 5/6hp and you can't do that.

[Limecc]

Shame it isn't a Merc/Mariner/Tohatsu 2.5 Where you can double the horsepower for the price of a cheap Chinese carb.

[909]

I'm a fan of overpowering vs underpowering.

Weather is unpredictable and can change in an instant.

A big heavy underpowered boat with extra passengers caught in bad weather can be disasterous.

Think of the kids. Safety first.

[Limecc]

Originally Posted by UKNick

Will only use it in calm water, or a slow running river, Never out at sea.

I'm with you on this but sounds like he knows what he's doing and the shoreline or riverbank will never be very far away.

As a 13 year old in a 3.5hp underpowered heavy boat I had a bad experience in a tidal river on the Broads, but that was my own fault due to inexperience and lack of knowledge/supervision. Distressing I couldn't get back but never dangerous.

[Max...]

A 2.5 might allow you to chug but it's way underpowered and the aircooled racket will drive you mad, like sticking a Trabant engine in a Transit. At least fit a 6 or 8 4 stroke for a more relaxed ride.

[GARYSHORT]

at least 5hp, up to 10hp

[Steve509926]

Sorry to say this UKNick but you already know the answer to the question you asked, you just hoped for a different answer.
You have to spend more money and buy a bigger outboard. Minimum 5/6 hp.

[billows]

I have a Honwave 3.5 alu deck with a 6hp Mariner. The engine is heavy but easily carried. It just about planes at 11 knots with me on board but am reduced to chugging about with two up. If you are considering a 6hp stay away from the Mariner as it is a pig to start compared to a Yamaha

[TmMorris]

My thoughts are that for just mellow chugging along a river you want an engine that will hold you at the mellow pace you want to move along at at a relaxing rpm. The 2.5 may get quite annoying as you might be running it with quite a bit of throttle.

Too big an engine and it might foul a bit due to running not far above tickover.

I would think that a 4 stroke 5hp would be about the sweet spot. Enough power if you need to manoeuvre but nice and quiet and you'll be running at a nice rpm that's good for the engine and one's relaxation?

[UKNick]

Originally Posted by TmMorris

My thoughts are that for just mellow chugging along a river you want an engine that will hold you at the mellow pace you want to move along at at a relaxing rpm. The 2.5 may get quite annoying as you might be running it with quite a bit of throttle.

Too big an engine and it might foul a bit due to running not far above tickover.

I would think that a 4 stroke 5hp would be about the sweet spot. Enough power if you need to manoeuvre but nice and quiet and you'll be running at a nice rpm that's good for the engine and one's relaxation?

Many thanks for your advice!

[TmMorris]

A 2.5 will do the job, it just may not be the best tool. Probably worth using it for a season first and during the season see if you can borrow something slightly larger just to see the difference.

I use an old 4hp 2 stroke on non tidal rivers and it has all the power I need while remaining easy to carry and lift on and off.

What I have noticed is that in recent years the noise it makes has begun to really stand out as more river users are on paddle boards, kayaks or using electric outboards.

Last summer I felt like I was revving a Saxo in a McDonalds car park on a few occasions.