Four Stroke and Water Skiing

ryanmollaun · 17 May 2012, 08:12

Hi,

I am purchasing a 6m RIB from China which weighs 640kg.

The manufacturer says a 150HP is the max and a 115HP two stroke is recommended. I am actually wanting a Four Stroke. Would a 130 - 150HP four stroke be capable of easily pulling out a 100kg water skiier without dragging them through the water for too long.

Also are the four strokes too heavy also?

The reason I ask is a relative suggested if we are wanting to ski, you shouldn't get anything other than a 2 stroke as the low down torque isn't sufficient in a 4 stroke.

I would love anyone's opinions on this.

Thanks everyone.

Ryan

Pikey Dave · 17 May 2012, 08:23

Hi Ryan, welcome to Ribnet.

First of all, I don't want to p1ss on your parade, BUT be very careful what you buy RIB wise from China, plenty of horror stories on here.

Accepted wisdom used to be, that 2 strokes were lighter, more responsive & had more lower down grunt. The gap is closing with the newer generation 4 strokes. Personally I'd go 2 stroke every time, they are simpler in construction, easier & cheaper to maintain & overall just as economical.
A 130-150 of whatever flavour should easily pull a skier on a 6m boat.
A 150 Etec will pull 2

ryanmollaun · 17 May 2012, 08:26

Thanks Dave - I am tending to think I really should be getting the 2 Stroke.

Would a 150 four stroke pull a skiier though sufficiently?

Thanks again,
Ryan

hadd · 17 May 2012, 08:27

Anything over a 50hp should be fine for skiing I've pulled a15 stone chap with a 70hp at the back of me with my last boat I had no problem

TomKat · 17 May 2012, 08:30

A mate has a 5.3m Tornado with a 75HP 4 stroke Suzuki and its a fantastic ski boat. Loads or what seems to me to be Torque. I would imaging the Chineese boat will be built light to save money on materials so you might be surprised how small and engine will pull skiers.

thomas · 17 May 2012, 09:08

If it helps, I bought my 6m with 115 4 stroke off a couple of wake boarders, it was plenty powerful enough just did not have much of a wake, once you get to a certain size the extra drag on the boat is a much smaller percentage.

ryanmollaun · 17 May 2012, 09:10

Quote:

Originally Posted by Pikey Dave

Hi Ryan, welcome to Ribnet.

First of all, I don't want to p1ss on your parade, BUT be very careful what you buy RIB wise from China, plenty of horror stories on here.

Accepted wisdom used to be, that 2 strokes were lighter, more responsive & had more lower down grunt. The gap is closing with the newer generation 4 strokes. Personally I'd go 2 stroke every time, they are simpler in construction, easier & cheaper to maintain & overall just as economical.
A 130-150 of whatever flavour should easily pull a skier on a 6m boat.
A 150 Etec will pull 2

Just another question - what 'horror' stories have you heard with the Chinese RIB's? I think a lot of RIB's these days are made in China now and I have heard a lot of known brands have now moved their operations to China and are still good as gold.

Thanks,
Ryan

kerny · 17 May 2012, 10:24

Quote:

Originally Posted by ryanmollaun

Just another question - what 'horror' stories have you heard with the Chinese RIB's? I think a lot of RIB's these days are made in China now and I have heard a lot of known brands have now moved their operations to China and are still good as gold.

Thanks,
Ryan

I guess in some cases yes that's true, but like the old saying... you only get what you pay for so if it sounds to good to be true for me it's a

I have had one and it was of poor build quality, here's a link to one story of a Chinese build. http://www.rib.net/forum/f8/spider-c...oat-38916.html and here's another http://www.rib.net/forum/f8/getting-...ose-39094.html

Both stories ended well as both of us got full refunds back on our ribs.

So hats off to the dealer involved.

Mollers · 17 May 2012, 11:07

Quote:

Originally Posted by Pikey Dave

Hi Ryan, welcome to Ribnet.

First of all, I don't want to p1ss on your parade, BUT be very careful what you buy RIB wise from China, plenty of horror stories on here.

Accepted wisdom used to be, that 2 strokes were lighter, more responsive & had more lower down grunt. The gap is closing with the newer generation 4 strokes. Personally I'd go 2 stroke every time, they are simpler in construction, easier & cheaper to maintain & overall just as economical.
A 130-150 of whatever flavour should easily pull a skier on a 6m boat.
A 150 Etec will pull 2

I'd agree with all of the above other than, 4strokes are actually better ski tugs. Low down torque, nice snooth pull out.
Etecs ideally, require re-mapping to make a decent ski boat motors. Mine is a nightmare, all or nothing pull out and doesn't like holding a steady lowish speed. A mm of loud stick may up the rpm by 500, which annoys the hell out of those on the end of the line.

ryanmollaun · 17 May 2012, 11:38

Quote:

Originally Posted by kerny

I guess in some cases yes that's true, but like the old saying... you only get what you pay for so if it sounds to good to be true for me it's a

I have had one and it was of poor build quality, here's a link to one story of a Chinese build. http://www.rib.net/forum/f8/spider-c...oat-38916.html and here's another http://www.rib.net/forum/f8/getting-...ose-39094.html

Both stories ended well as both of us got full refunds back on our ribs.

So hats off to the dealer involved.

Wow - you had me worried for a minute there. I did a bit of research and digging and found that the weights of the SeaPro RIB's which are the lemons you were referring to are in fact more than 50% lighter than they should be.

I referred to our manufacturers spec sheet and compared it to SeaPro's here...
SEAPRO :: Seapro Ribs

For example... Their 520 model is 165kg whereas the manufacturer I am using is 400kg. SeaPro's largest model is 720 which is 520kg whereas our manufacturer is 800kg.

So I think it is a manufacturer specific problem in that they are obviously using paper thin fibreglass in their hulls.

It is unfortunate I think that they would be so irresponsible to sell such crap really. Few extra $$$ to make a stronger hull and they might be a good RIB.

Here is a link to the one we are getting made...

Rigid inflatable boat with teak floor - Detailed info for Rigid inflatable boat with teak floor,RIB boat,Rigid inflatable boat with teak floor,Rigid inflatable boat with teak floor on Alibaba.com

ryanmollaun · 17 May 2012, 11:44

Quote:

Originally Posted by thomas

If it helps, I bought my 6m with 115 4 stroke off a couple of wake boarders, it was plenty powerful enough just did not have much of a wake, once you get to a certain size the extra drag on the boat is a much smaller percentage.

Sweet!

Well I think ideally I want a 4 Stroke because it is quiet and reliable.

The boat we are getting will be 590kg dry weight without fuel + motor. I guess this is relatively light?

I think I will chase up a minimum 115HP but hopefully a 130HP and this should be sweet I guess.

Pikey Dave · 17 May 2012, 11:55

Quote:

Originally Posted by Mollers

I'd agree with all of the above other than, 4strokes are actually better ski tugs. Low down torque, nice snooth pull out.
Etecs ideally, require re-mapping to make a decent ski boat motors. Mine is a nightmare, all or nothing pull out and doesn't like holding a steady lowish speed.

That's down to the "instant" power of the 2 stroke, whereas the 4 stroke needs to think about it for a day or so before it decides what to do & then slooooowly gets out of bed

I agree about the etecs, they like to be off, mine hate chugging about in the 1500-2500 rpm range

Mollers · 17 May 2012, 13:14

Quote:

Originally Posted by ryanmollaun

Sweet!

Well I think ideally I want a 4 Stroke because it is quiet and reliable.

Quiet at tick over and reliable until they go wrong. Outboards go wrong if they are poorly maintained, whether they're 2 or 4st, it makes no difference.

I wouldn't want a Chinese built rib as a gift.

Do yourself a huge favour and buy a used UK built rib for the same money.

Also, run it buy this forum before shelling out cash.

kerny · 17 May 2012, 14:06

It is unfortunate I think that they would be so irresponsible to sell such crap really. [/QUOTE]

Unfortunately China is where a lot of the crap comes from

I'm sure that you have done your research well and I hope that you particular rib is one of the good ones and that you have many years enjoyment out of it

Oscarguitar · 17 May 2012, 17:37

I have had a 4m Avon with a 40hp four stroke and a 5.6m Avon with a 100hp four stroke both were capable of pulling skiers and wakeboarders. The 4m could be a little tardy but the 5.6 had no problem at all and was great with less experienced people as the pick up was so smooth. I agree my brothers 5.8m Ribcraft (or Ribtec) with a 115hp two stroke was far more ballistic, but often left the skier in the water and the handle making its way through the air back to the boat!! Either will serve you well if you get a good one and keep up with the maintanence.

Best advice is to use it often and open it up, thats what outboards are built for and thats what they like best! They just hate tootling about or being left alone all winter to corrode while the winter gremlins get to work.

I would also put in a vote for a decent secondhand boat from a manufaturer with a good reputation, it is not just about weight, structure and design is just as important as lay up weight. Any fool can keep slapping on the layers of glass, but designing in strength and sea keeping is an art that not all builders have.

Whatever you get enjoy your boat and let us know what you decide and how you get on.

Downhilldai · 18 May 2012, 00:27

Quote:

Originally Posted by Mollers

I wouldn't want a Chinese built rib as a gift.

Do yourself a huge favour and buy a used UK built rib for the same money.

He's in Oz though, Mols.

Mollers · 18 May 2012, 08:03

Quote:

Originally Posted by Downhilldai

He's in Oz though, Mols.

I did notice that, but still reckon my comments stand.

Which non-European built ribs actually cut the mustard?

Rayglass Protector
Military spec Zodiac...

Pikey Dave · 18 May 2012, 09:28

How much is a shipping container to Oz these days? Boggy managed to get Seawolf to the Malv.......sorry!... Falklands.
Thread drift

PS just had a quick Google, $170 US/m3 or 1000kg for containers from London to Oz

Downhilldai · 18 May 2012, 10:41

Apherel imported a new 5.8 Vipermax to Oz, so he may be able to help on costs.

BumbleAbout · 18 May 2012, 10:57

A few years ago it used to be about USD400 to ship a 40ft container from port to port - anywhere. You can then easily triple that cost moving the container to/ from the port at either end - so if you could "simply" drive your RIB on a trailer into a container at the port in the UK and do the opposite in Australia, then it's a very cheap option (ignoring Australian import duties for the moment - which I don't know about). I thought that global shipping costs had dropped sharply in the last few years however, so it might be cheaper now.