Small rib vs large SIB

two stroke mick · 10 October 2007, 20:08

I am wondering what are your views on a large sib e.g 5m humber or 4.7m zodaic vs a small rib e.g 4.5m valiant. Your thoughts on Comfort,dryness, use for beaching etc

As I have an ex RNLI 40 hp mariner either type of boat may suit (18" shaft, tiller steer, Two stroke)

Does anyone know of a dealer for Gemini in the UK or Ireland?

codprawn · 10 October 2007, 22:33

How about a good old compromise - a Zapcat??? Awesome beasts!!!

two stroke mick · 10 October 2007, 22:43

The boat would be used for the family. I have considered a zap cat but I don't think it would suit for diving, snorkling etc

ian parkes · 10 October 2007, 23:26

Having just old a 4.9 valiant an bought a mk3 futura 4.5 m the difference is "chalk and cheese" there is no comparison IMo between a sib and a small rib .

Even the big futura is very bouncy and uncomfortable in any sort of chop , where the rib used to just skim over the top without even noticing it .

Advantages of the sib are more space if its tiller controll , much quicker turning and fun for messing about in surf etc plus you can use transom wheels or even carry it with a few hands .
If you don't want to go far and want to land in small coves etc then the sib is great .

Worst part of the new sib for me was the fuel ecomomy from the yam 25 2 stroke . It used just as much fuel as the DF70 on my rib but did just over half the speed .

ian parkes · 10 October 2007, 23:31

Quote:

Originally Posted by two stroke mick

I am wondering what are your views on a large sib e.g 5m humber or 4.7m zodaic vs a small rib e.g 4.5m valiant. Your thoughts on Comfort,dryness, use for beaching etc

As I have an ex RNLI 40 hp mariner either type of boat may suit (18" shaft, tiller steer, Two stroke)

Does anyone know of a dealer for Gemini in the UK or Ireland?

gemini dealers are gone bust I think in UK , couldn't contact them at all and emails returned .

If you want to make good use of that engine it would be great on a BIg futura if its a long shaft , but get the alloy floor , I reckon 40 hp would buckle the air floor from the feeling I got with mine in waves .

two stroke mick · 11 October 2007, 09:10

Thanks Ian

I am leaning towards a tiller steered rib circa 4.5m like the DR450. I would like a boat that could cover circa 15nm without been too rough on the passengers.
The boat would have to be light enough to be launched and reterved on poor quality, steep slips with a two wheel drive car.
I also woul like to be able to beech the rib. I think that I will have to remove a section of the transom by 2 " as the shaft lenght is 17.5 or 18 " not a 20" long shaft

9D280 · 11 October 2007, 09:29

SIBs - good if you plan to beach a lot, coz they have next to no draught. Somewhat uncomfortable in anything other than flat water when on the move.

RIBs - good on the move, but a tad more of a pain to beach.

As for room, why not have a tiller control RIB? The old 3 cyl Yam 30 went quite nicely as tiller control on the Avon SR4. Infinitely more manoeverable as well on the tiller. Also if ytou go tiller, you've just saved the weight of a console, which oin a smaller rib might not be a bad thing.......

Channel Ribs · 11 October 2007, 10:37

Quote:

Originally Posted by two stroke mick

As I have an ex RNLI 40 hp mariner either type of boat may suit (18" shaft, tiller steer, Two stroke)

The seakeeping of a good SIB is not to be sniffed at, obviously they cannot compete with a hard deep v and a narrow beamed RIB, but they are capable and fun.

The main difference, since you already have an engine, is going to be performance; a big 5.3m SIB is going to be far lighter than a 4.5m RIB.

The next big difference is value, for the same money you will get the boat and launching wheels

some nice gadgets and maybe even a trailer.

This is smaller then you are after, but it gives you an idea of the level of gear you can get for your money:
http://www.boatsandoutboards.co.uk/view/MHM141

Cheers,
Martin

two stroke mick · 11 October 2007, 12:52

I think a SIB would be too bouncy and wet for covering any distance greater than 3 or 4 miles. I believe that a small tiller steered rib would provide a dryer, faster and more confortable ride. I do not intend messing about in the surf. With respect to beaching the boat would be used to get on and off a beach not fooling around in the surf.

Has anyone out there a small Tiller steer rib? If so how do you find it? what are it's limitations?

samt · 11 October 2007, 13:31

My searider is tiller steered. Although I eventually plan on fitting a console.

I'v been using a 25hp. It is very manouvrable and the boat is very light, however I find it difficult to use on my own without weight in the bow. But with extra passengers its fine.

The main problem is that you don't feel as safe or as confident as you would if you were using a console. Make sure there are plenty of handles and ropes for you and your passengers to hold on to.

two stroke mick · 11 October 2007, 13:48

Thanks samt. do you find the boat bouncy. do you sit on the sponsons or have you a bench that sits accross the tubes

samt · 11 October 2007, 14:09

I sit on the sponsons, the boat originally had a bucket seat arangement, and covered bow. Sitting on the sponsons is fine, providing you have somthing strong to hold onto.

I haven't found the Rib bouncy, but I havn't used it much so far, there are loads of other members with more experience with SR4's. I believe the searider has quite a deep V compared to alot of other similar sized ribs so provides a much smoother ride.

prairie tuber · 11 October 2007, 14:34

When discussing the ride characteristics of a SIB it is important to distinguish if you are describing one with the traditional inflatable V keel (95% of the SIBs out there), or a cat hull or a hybrid of the 2.

Zodiac's futura hull is a hybrid in that it has both a central inflatable v keel along with 2 small speed tubes. The speed tubes create lift which makes this hull much quicker and more efficient than the traditional SIB hulls. It will also reduce the bounciness of the boat somewhat.

The cat hulled SIBs would include the pencil boat style racers zapcats/thundercats & the thunderbolt (Ceasars 5.3m version of a thundercat). It would also include the round nosed cat hulls, Gemini's Surf (4.0m 4.2m) series & Dive (4.7m 5.3m) series, and Ceasar's Surfcat. For general use where you will carry a fair bit of gear/people and want a dry ride, I'd stick with the round nosed hull. For longevity I'd choose hypalon over PVC.

The true cat hulled SIBs with their much larger highjackers and no central keel will provide a far much smoother and drier ride in choppy conditions than the hybrid design since the highjackers are able to deflect and dissipate a tremendous amount of energy away from the main sponsons on landings. The pictures below show the difference between a 4.2m futura hull (left) and that of a 4.2m Gemini Surf.

RibinSpain · 11 October 2007, 18:13

thanks to all contributors to this thread as I was thinking of getting a SIB but having found the Med too choppy for a 5m RIB, would find it even worse in a SIB.

The SIB benefits seemed just too good to be true - easy launch, store in the back of car, no trailer, small ob, can row out of trouble, cheap to buy & maintain etc etc. However, out of 20 outings this summer there were only 2 flat water days so the SIB would not really have suited.

Saying that it is also a confidence thing, some days when we were out & found it choppy (say 5 ft waves but felt like more) we saw a SIB out there & the occupants looked q happy.

Thanks all, interesting posts

Mr Flibble · 11 October 2007, 19:36

I have an old 5m Humber inflatable I use for diving.

Advantages:
Easy to tow, I used a Ford Fusion 1.4 tdci and you wouldn't even know it was on the back.
Easy to launch/retrieve.
Lots of deck space as it has a 40hp tiller steer.
Great for diving the Lochs up here.

Disadvantages:
Seaworthiness, was out it a brisk sea earlier this year going from Oban to the Sound of Mull across the Firth of Lorne and we got buffeted quite a bit by some biggish waves, we got there and back OK, just took a bit longer and my biceps grew in size trying to keep the boat going straight in a strong breeze.

I'll be upgrading to a RIB next year as I'm looking for something that will take me a bit further offshore.

ian parkes · 11 October 2007, 19:39

Quote:

Originally Posted by RibinSpain

thanks to all contributors to this thread as I was thinking of getting a SIB but having found the Med too choppy for a 5m RIB, would find it even worse in a SIB.

The SIB benefits seemed just too good to be true - easy launch, store in the back of car, no trailer, small ob, can row out of trouble, cheap to buy & maintain etc etc. However, out of 20 outings this summer there were only 2 flat water days so the SIB would not really have suited.

Saying that it is also a confidence thing, some days when we were out & found it choppy (say 5 ft waves but felt like more) we saw a SIB out there & the occupants looked q happy.

Thanks all, interesting posts

The sib is worse in a small chop , its actually a lot of fun in big rolling sea when the wave faces are big enough to get the whole boat on .

That surfacat looks way better than the futura hull the way it sits on the water .I think that would be my choice as it takes a short shaft motor.
having now owned and used the futura its really not much better than the air floor Honda , its really only gaining anything because its longer and I don't really like the flat cornering it feels far less secure and you back off sooner for fear of falling out .

I would bet the Honda 4m with an alloy floor is an equal to the Futura for half the price

9D280 · 15 October 2007, 09:37

I had a bit of experience with one of these and a Yam 30 a few years ago. The best way I found to "wedge" myself in was to sit against the inside of the port toob, wedging my foot against the stbd transom brace, and hanging onto the "recovery rope" with the hand I wasn't driving with. Granted that engine had the "new" (eek - was it that long ago???

) centre positioned gearshift. An older engine with the traditional "shift on the stbd side" might need you to sit to stbd for close quarters manoevering. Memory says that engine also had a tiller that pointed vaguely to port as well, which made a stbd sit very uncomfortable, but put it right where you wanted it on the port side.

Once wedged in like that I bounced through all sorts of evil chop quite happily. Needless to say we lashed the fuel tank up at the bow to get some more weight forward.......