3.4m vs. 3.6m 4.9HP SIB

Southkorea · 29 June 2018, 00:52

Hi all,

This is my first post on the site. I found this forum through a trail of agonising google searches. I'm trying to decide between a 3.4 or 3.6m SIB with removable aluminium floor.

I live in South Korea and the regulations here limit boaters with no licence to 4.9hp. I intend on getting the licence but I will need to improve my Korean before I can do that (+- 1 year).

I would like to buy a SIB and pair it with my Merc 4.9 2strk but want to get one that will work well with a 15hp or 9.8hp Tohatsu in time to come.

My question is whether there will be a noticeable difference between a 3.4 and a 3.6 being powered by a 4.9hp? The 3.6 would be ideal when I upgrade the motor but will it be a tank in the water with a 4.9hp?

The 3.4 weighs 52kg and the 3.6 weighs 72kg. I weigh 90kg. Inshore use only, the region I'm in has calm'ish seas but large tidal variances.

Any suggestions would be appreciated - info in English here is scarce.

Lee1 · 29 June 2018, 01:21

20kg is a big difference between a 3.4 and 3.6 they might have thicker material or different thickness transoms?? thicker is always better! Both will go the same with the 4.9 and they will probably go the same with the 15hp 3.4 and 3.6 difference is only 20cm! get the 3.6 if you want lots of room or get a 2.9-3.2 for speed over room if that's what you want, what makes and model have you decided on?

If your set in a decision between the two you posted and you are sure you will get the bigger engine licence get the bigger one if not get the smaller one, 20kg will add up on the general overall weight if you don't get more that the 4.9hp

Southkorea · 29 June 2018, 01:38

Correction 57kg for the 3.4m. I'm buying in Korea. There are some nice locally made SIBS here, the market for them is huge. 3.4 is rated to 15hp and 3.6 to 20hp. theres a 160 Sterling price difference between the two-not a game changer but it would cover the price of the fish finder

Lee1 · 29 June 2018, 01:46

Once licenced can you use a 20hp right? If so get the bigger boat and get a 20hp if you won't end up getting the licence get the smallest and lightest size your comfortable with because you will be using the 4.9 which is going to struggle to get past 8knots or so even on a 3.2 meter boat factoring in its hull design, also consider you may have up to a 4knot or possibly more ocean tide current, I'm not knowledgeable on your ocean tides etc.
What make 4.9 engine are you going to use, 2 or 4 stroke, new or old?

Southkorea · 29 June 2018, 01:57

Quote:

Originally Posted by Lee1

Once licenced can you use a 20hp right? If so get the bigger boat and get a 20hp if you won't end up getting the licence get the smallest and lightest size your comfortable with because you will be using the 4.9 which is going to struggle to get past 8knots or so even on a 3.2 meter boat also consider you may have up to a 4knot or possibly more ocean tide current, I'm not knowledgeable on your ocean tides etc.
What make 4.9 engine are you going to use, 2 or 4 stroke, new or old?

Thank you for the advice! Think I will go with the smaller and just bite the bullet when I'm licenced and buy a RIB.

Lee1 · 29 June 2018, 02:01

For 1 person, the occasional passenger and fishing kit 2.9-3.2 is ideal you can always sell it once you have your licence! Go as small and as light and as best performing as you can, and post some pics

lightning · 29 June 2018, 23:32

The 3.2m boat should get on the plane with one person on board using a 5hp engine.
My 2.8m (solid floor inflatable keel) SIB managed 14mph with a 6hp with two of us on board combined weight around 140kg.
So l would say you might get 12-14mph if you sit forward while it gets going, perhaps with a tiller extension.
The 3.6m might be on the limit planing with a 5hp but it will be a better boat when you get the larger engine.

Southkorea · 04 July 2018, 05:34

Quote:

Originally Posted by lightning

The 3.2m boat should get on the plane with one person on board using a 5hp engine.
My 2.8m (solid floor inflatable keel) SIB managed 14mph with a 6hp with two of us on board combined weight around 140kg.
So l would say you might get 12-14mph if you sit forward while it gets going, perhaps with a tiller extension.
The 3.6m might be on the limit planing with a 5hp but it will be a better boat when you get the larger engine.

Ended up going with a 3.3m. Going to buy a RIB when the time comes.

Lee1 · 06 July 2018, 04:00

What 4.9 engine are you using?

Southkorea · 06 July 2018, 04:40

Quote:

Originally Posted by Lee1

What 4.9 engine are you using?

Mercury

Southkorea · 06 July 2018, 05:34

Quote:

Originally Posted by Southkorea

Mercury

If the weather plays along I'll give it a run this weekend. The squid and dorado have just arrived on our island