Recommended Engine Size for 3.5m Inflatable?

[Don Logan]

Hi,

I'll be buying a Honwave t35AE (3.5m, aluminium floor) soon and am looking at outboards for it. I'm after some advice on what size to go for in terms of HP. The boat is rated for a 20hp/ 55kgs engine which made me think that that's what i'd go for. I think i could manage lugging it out of the boot of the car onto a trolley and the dingy would have transom wheels, so i think i should be able to just about cope with the weight, plus there will usually be two of us.

The boat would be for general leisure use, taking wife and two kids out, some fishing with a couple of other adults, etc. I'd like it to be able to tow a ringo or kneeboard or similar too. I know i won't be wakeboarding with this setup, but i'd still like a bit of speed. Does 20hp sound about right for this on this sized boat? I looked at 15's and they seem to weigh in at the same as a 20, so a 20's what i've been looking for so far.

Also, I've budgeted around £1000ish for a used engine. I've seen from looking online that that can mean an engine at this size anywhere from 5 to 25 years old. Even the adverts for the newer ones in a higher price range rarely mention anything about paperwork or service history. Would it be fair to say to stay away from anything without paperwork or service history? I really don't fancy having it breakdown on the south coast with two toddlers on board, but can't afford to buy brand new at this engine size.

Any advice regarding engine size or buying secondhand would be appreciated, i do know about checking compression and impeller function, etc. but not a great deal else about outboard motors.

Thanks in advance.

[Fenlander]

Hello and welcome Don. I had a 3.5AE until last year. I thought it a well made and very stable SIB... only sold as for our use it was a bit heavy. We had a mint Mariner 15 2-stroke which is as much as I can lift easily but in truth if you can lift a 20 the 3.5AE would appreciate that bit of extra power.

You very rarely get any sort of history with outboards other than verbal claims/truths so it's usually a case of weighing up the seller. My experience over the past 25yrs of many outboards in the 2-25hp range is that on the whole they are little used, keep in good condition and stay very reliable.

Having said that if you can stick to the latter end of availability of 2-strokes being sold new... years 2000-2006.

[dave3235]

[QUOTE=Don Logan;678982]Hi,

I'll be buying a Honwave t35AE (3.5m, aluminium floor) soon and am looking at outboards for it. I'm after some advice on what size to go for in terms of HP. The boat is rated for a 20hp/ 55kgs engine which made me think that that's what i'd go for. I think i could manage lugging it out of the boot of the car onto a trolley and the dingy would have transom wheels, so i think i should be able to just about cope with the weight, plus there will usually be two of us.

The boat would be for general leisure use, taking wife and two kids out, some fishing with a couple of other adults, etc. I'd like it to be able to tow a ringo or kneeboard or similar too. I know i won't be wakeboarding with this setup, but i'd still like a bit of speed. Does 20hp sound about right for this on this sized boat? I looked at 15's and they seem to weigh in at the same as a 20, so a 20's what i've been looking for so far.

Also, I've budgeted around £1000ish for a used engine. I've seen from looking online that that can mean an engine at this size anywhere from 5 to 25 years old. Even the adverts for the newer ones in a higher price range rarely mention anything about paperwork or service history. Would it be fair to say to stay away from anything without paperwork or service history? I really don't fancy having it breakdown on the south coast with two toddlers on board, but can't afford to buy brand new at this engine size.

Any advice regarding engine size or buying secondhand would be appreciated, i do know about checking compression and impeller function, etc. but not a great deal else

Hi

You never said if you were buying new or 2nd hand boat.I would go for the 4mtr not enough room for 4 really,you would want more space .Also a 25 or even a 30hp weight is the same if your but will stretch.

[dave3235]

[QUOTE=dave3235;678985]

Originally Posted by Don Logan

Hi,

I'll be buying a Honwave t35AE (3.5m, aluminium floor) soon and am looking at outboards for it. I'm after some advice on what size to go for in terms of HP. The boat is rated for a 20hp/ 55kgs engine which made me think that that's what i'd go for. I think i could manage lugging it out of the boot of the car onto a trolley and the dingy would have transom wheels, so i think i should be able to just about cope with the weight, plus there will usually be two of us.

The boat would be for general leisure use, taking wife and two kids out, some fishing with a couple of other adults, etc. I'd like it to be able to tow a ringo or kneeboard or similar too. I know i won't be wakeboarding with this setup, but i'd still like a bit of speed. Does 20hp sound about right for this on this sized boat? I looked at 15's and they seem to weigh in at the same as a 20, so a 20's what i've been looking for so far.

Also, I've budgeted around £1000ish for a used engine. I've seen from looking online that that can mean an engine at this size anywhere from 5 to 25 years old. Even the adverts for the newer ones in a higher price range rarely mention anything about paperwork or service history. Would it be fair to say to stay away from anything without paperwork or service history? I really don't fancy having it breakdown on the south coast with two toddlers on board, but can't afford to buy brand new at this engine size.

Any advice regarding engine size or buying secondhand would be appreciated, i do know about checking compression and impeller function, etc. but not a great deal else

Hi

You never said if you were buying new or 2nd hand boat.I would go for the 4mtr not enough room for 4 really,you would want more space .Also a 25 or even a 30hp weight is the same if your but will stretch.

Sorry !!! Ment to say budget

[jonp]

Always go for the max if you can afford to. Most of the time a bigger engine ends up costing less in the long run, they don't have to works as hard so can sit in a lower rpm range using less fuel. You also have extra power with heavy loads that a small engine may not even get you on the plane with.

Boating should be about having fun, you tend to have more fun with more power!!
Jon

[Don Logan]

• Thanks for the replies. Well regarding getting the 4metre instead of the 3.5, it will very rarely have more than two adults and two kids to be honest and the second hand 3.5 that I've seen is a good price and includes transom wheels. Also, it needs to be half portable which is why I thought I'd stick to the 3.5
• Regarding a two stroke over a four stroke: are they any more reliable? Any problem laying them down in the boot of a car? Many thanks...

[Max...]

Where are you launching? You'll struggle around here unless you're going to the slip at Newhaven. A 15 hp 2 stroke is manageable down the beach, forget a 25 4 stroke unless you are both big fit young and strong.

It's all about compromise but a 15 2 stroke is the best compromise for 3.5m SIBs. Some info in the sticky Which Sib above too and in a gazillion other similar topics!

Re' towing, if you have growing toddlers then they will be too small for toys I guess but my young son (size of a 10 yr old) can easily kneeboard behind our rig. I would not attempt this with an adult especially with toddlers on board as you need a driver and an observer, boat will be very unsteady as they are so light.

If you're new to this look at doing the PB2 first and the VHF course is a must if going to sea.

[jonp]

You also have the fact that two strokes are smelly compared to 4 strokes, as soon as my kids got a whiff of two stroke smoke they were spewing over the side not wanting to go again (until I bought a 4 stroke). Most modern 4 strokes are close to the same weight as 2 strokes.

Suzuki 20 4 stroke 44kg
Suzuki 30 2 stroke (no 20 hp) 57kg
Suzuki's EFI 15/20hp Portables Boat News, Review & Advice - boatpoint.com.au
Jon

[dave3235]

Hi

Pacer Marine are selling 4mtr for £950 plenty of growing room.Two adults 2 kids you will not be comfortable especially with some kit on.

[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.

[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.

It's a 3.5 With aluminium floor

[Don Logan]

Originally Posted by Max...

Where are you launching? You'll struggle around here unless you're going to the slip at Newhaven. A 15 hp 2 stroke is manageable down the beach, forget a 25 4 stroke unless you are both big fit young and strong.

It's all about compromise but a 15 2 stroke is the best compromise for 3.5m SIBs. Some info in the sticky Which Sib above too and in a gazillion other similar topics!

Re' towing, if you have growing toddlers then they will be too small for toys I guess but my young son (size of a 10 yr old) can easily kneeboard behind our rig. I would not attempt this with an adult especially with toddlers on board as you need a driver and an observer, boat will be very unsteady as they are so light.

If you're new to this look at doing the PB2 first and the VHF course is a must if going to sea.

Will be launching at Newhaven I expect and also saltdean as we can park by the cafe and walk down to the slip.

I am indeed fit young and strong, and as said, there will nearly always be two of us, so I'm hoping the weight will be ok.

I'll be sensible with the towing, the kids are too young anyway, it would still be nice to have the option in future or whatever...

I was actually going to ask about the vhf course and buying a radio. The course can be done online can't it? The info I saw mentioned an online course for 75 quid and then going somewhere to do the exam for another 60...

Then it's a hundred odd quid for a handheld radio?

Does that all sound about right? What's the PB2?

Thanks.

[Max...]

You can do the PB2 (basic 2 day boat handling course) and VHF course at Sovereign Harbour, that's where I did mine. If you have no experience of boats and are seriously taking your family to sea then these two courses are a must. As well as making sure you have all the safety gear, VHF etc with you.

Level 2 | Powerboat | Courses | Learning | Courses & Training | RYA

[blootac]

Personally, I'd go somewhere and do the VHF course in person.
You'll learn more and can ask questions. The VHF course will be something you'll later come to rely on if you get into difficulties, so in my opinion, saving £40 or whatever shouldn't really come into it when you could need the knowledge from a question you asked to save someone's life.

Just my view though.

[blootac]

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.

I agree with Max.
We always have an Avon Rover 340 with two adults and two teens. Although I now have a 3.8 and appreciate the space, the 340 was always sufficient

[kestrel452]

From my limited experience owning a 3.5m aluminum floor Zodiac, you should go ahead and buy a 20HP engine if you want the most performance from your boat. I'm finding the tuning process to get my boat planing with a 15 to be incurring some additional (but not outrageous) expenses. Of which are: lower pitch prop and a Permatrim hydrofoil. Also, seating space on a 3.5m boat starts becoming a commodity after four adult souls climb on board, but 3.5m is about the max for a "portable" rig IMHO.

That being said, do not think for one second that it's going to be easy (or even only moderately difficult) to lift and mount/dismount that motor each time you go to use the boat. I have a 2-stroke 15HP Merc, that while may not give me awesome performance, is about the upper max I can lift out of the vehicle on my own. It's only 76 lbs, whereas *any* 20HP motor regardless of type, will weigh in at 110-120lbs. It sucks, but even 2-stroke 20's weigh in that much heavier. An almost 80 pound object with the vast majority of the weight at one side is awkward enough as it is. I'd really recommend at least a cheap trailer to store the boat on so you don't have to lift the motor off and on all the time.

For me, I knew I needed a portable rig, no room to store a trailer. If that's your situation too, go for a 2-stroke 15. I haven't found them to be overly smelly/dirty/noisy; they're not as refined as a 4-stroke but they do their job reliably. If your 2-stroke is so smelly that it's suffocating passengers, it needs a tune-up If you know you'll always have another physically fit male to help you lift the thing, go for the 20, just realize you'll find yourself loathing going to use the boat if you don't.

[Callum Stewart]

Have a look in the for sale section of ribnet

I have a nice 3.2 honwave with a 9.8hp I was offered a 9.8 or a 15hp and picked the 9.8 a 15hp is near the limit weight for one person to lift and fit to the sib when at the water!

Gone are the days when my brother and I had a 40hp on a sib for diving

All the best Callum.

[Don Logan]

Thanks for the advice, i'll have a think. Being as there will nearly always be at least two of us i'm still leaning towards a 20 though...

There seems to be a lack of used 20hp's around online for my budget of £1000 unless i want something from the early to mid 90's, which i'm inclined to avoid due to not having a great deal of knowledge of outboard motors. Unfortunately it's not like buying a used car where you can check mileage and service history at least. It seems like i'd have to put a lot of trust in the seller, or spend more money and buy used from a dealer offering a warranty.

I'd be tempted to up the credit card limit and buy new, however we're moving to Australia next year and i don't think i'd be able to transfer a new warranty to another country. Someone did suggest buying here and then registering in Australia, although that sounds like a good reason to be told to go away if you ever have to claim. Saying that, how likely are warranty claims on new motors from decent manufacturers? Is any problem on a new motor likely to be expensive?

Thanks again...

[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.

[Fenlander]

>>>Being as there will nearly always be at least two of us i'm still leaning towards a 20 though...

Don have you tried lifting any 15/20/25hp outboards with just you or two of you?

It's not just about the weight.. heavier ones are utter pigs for balance and where to hold if a second person helps. Apart from the handle near the clamps there is nowhere else for a second person to get a good grip to assist. Likewise if they try and lift the skeg end it almost seems to add weight.

One answer though is to make up a short pole that can hook onto the handle and then the two people can carry on the point of balance. Like a variation on the simple but effective old Seagull carry handle...

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