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Old 24 November 2007, 05:35   #41
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Country: UK - England
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Length: 3m +
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Originally Posted by malthouse View Post
Why not a mid-sized inflatable with a small jockey console?

BTW You will find the 3.8 goes nicely with a 20. I can dig some figures out for you if you like?
Thanks Malthouse. I'm trying to keep the boat as portable as possible, so will stick to the tiller option. Probably also need to go 30hp from what Trickdog says, as I will inevitably have most of the family with me most of the time.
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Old 24 November 2007, 05:41   #42
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Originally Posted by Trickdog View Post
Lordy

I expect that a 20 or 25hp would be OK on a 3.8m SIB. The big difference I noticed with the 20hp was some difficulty getting the boat onto the plane when carrying a lot of weight (by that I mean 4 or 5 people... There was no problem with only 2 on board). With the 30hp the boat planes very easily even when carrying 6 people. I am definitely getting more speed out of the 30hp also but, as I mentioned, it takes some effort keeping the boat straight at full throttle.

I think the 30hp tiller steer was a good compromise. There is plenty of space for carrying people and gear to the beach, but also enough power to do some decent exploring trips around the coast. I am happy to lose a little manageability for all the extra space in the boat that tiller steering provides. And I still take the boat out on some long runs in fairly choppy conditions. A SIB jumps over waves rather than cutting through them, so you get shaken about a bit in rough water, but that would happen whether you had tiller steering or a console.
Thanks Trickdog - very valuable advice this, particularly with a family of 5.

So, I'm going to go 30, but I wonder if there is any way of somehow stabilizing the steering. I'm sure I've seen something about stabilizers, if that's what they do.
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Old 24 November 2007, 05:55   #43
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Originally Posted by prairie tuber View Post
For a given outboard power and a given SIB length, an inflatable 'v' keel will require more 'strongarming' of the tiller to keep it tracking straight than a futura hull. A straight catamaran hull will require less still. If you are wondering about the differences in these hull designs, there is an expalanation of them here; Small rib vs large SIB . Also, when comparing different lengths of SIBs that have the same general hull design, the shorter the hull, the more effort you will have to put into the tiller to keep going straight.

For example, when I put my 40 hp outboard on my 4.2m zodiac SIB with an inflatable 'v' keel (which is it's max hp rating), it requires alot more effort to keep it straight than when that same outboard is on my 4.7 m Gemini with the catamaran hull (see picture below). This is because of both the difference hull length and the difference in hull design. With the 40 hp outboard on the Gemini, it takes minimal effort on the tiller to keep it going straight while on calm water, and moderate - substantial effort when going thorough strong or whirlpoooling currents such as below.
Hello again Prairie Tuber

Yes, after your previous advice I've been trying to find out more about the types of hulls you refer to. They sound ideal for my situation - slightly nervous kids - but haven't been able to find many options with speed tubes. Are they pretty unique to the Zodiac Futura models and the faster racing-type cats?

Mind you, the prospect of meeting any of those whirlpooling currents doesn't exactly fill me with joy. Looking at all you fantastic pictures, though, I suspect you approach to RIBbing is somewhat hardier than what I am planning!

Happy Thanksgiving, btw. (Or is that just an American tradition?)
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Old 24 November 2007, 09:40   #44
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Country: Canada
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Originally Posted by Lordy View Post
Hello again Prairie Tuber

Yes, after your previous advice I've been trying to find out more about the types of hulls you refer to. They sound ideal for my situation - slightly nervous kids - but haven't been able to find many options with speed tubes. Are they pretty unique to the Zodiac Futura models and the faster racing-type cats?

Mind you, the prospect of meeting any of those whirlpooling currents doesn't exactly fill me with joy. Looking at all you fantastic pictures, though, I suspect you approach to RIBbing is somewhat hardier than what I am planning!

Happy Thanksgiving, btw. (Or is that just an American tradition?)
Lordy,

Thanks. We Canadians also celebrate Thanksgiving, but in early October since the end of our harvest season tends to be somewhat earlier than that of our American friends.

In the very first page of this thread I had posted several links to some previous RIB.net threads related to SIBs. There is alot of info in there that you will probably find helpful. I've also posted a few pics in the gallery section of my rig in a thread titled "Pics form the Weekend - Last outing of the season".
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