My first RIB. Yippie!

tworotorturbo · 04 March 2013, 22:39

Greetings from California, USA. I recently picked up a 1998 Avon SR4 to replace my 1988 Avon S400 SIB. Now I need to find a jockey console and a motor. Here are a few pics so far, its a bit dirty but I think it can clean up nicely.

Does anyone know if this hull (loaded with motor, console, passenger) is able to float even with the tubes deflated? Its a flooding hull and I don't plan on blocking it.

Tim M · 04 March 2013, 23:26

Quote:

Originally Posted by tworotorturbo

Does anyone know if this hull (loaded with motor, console, passenger) is able to float even with the tubes deflated? Its a flooding hull and I don't plan on blocking it.

Looks really nice - even more so with a console fitted! With regards floating, that's an interesting one. Inside the flooding area is a buoyancy tank which you can't really see. Not sure if this would be enough to support the weight of the whole thing if the worst happened. Even if it was, the bow would probably sink below the waterline as the tank is at the back.

Locozodiac · 04 March 2013, 23:44

Welcome to Ribnet,

What's the use of a flooding hull, apart from adding more weight to the rib and probably lessening some top end speed, is the ride more stable than with a non flooding hull ? nice size rib, congrats!!

Happy Boating

JamesF · 05 March 2013, 00:30

They make a good stable platform at rest with the hull flooded. I wouldn't have thought it made much difference, if any at all, to the top speed. If you're paying attention, you do notice the weight changing as you accelerate and the hull drains, though.

The worst thing you can possibly do to an SR4, though, is block the vent holes off without doing the drain hole as well. Combine that with a 25hp motor, and you've turned an excellent boat into a slow, heavy thing that needs a run down-sea before it'll happily go into it.

I've wondered myself whether it would float without the tubes. We have had a puncture once, but that only affected one section. I wouldn't particularly like to be the one to find out first-hand.

That looks a really nice, tidy example.

Locozodiac · 05 March 2013, 12:33

So at rib rest assume the hull fllods completely, once rib is underway water starts to exit through back vent hole, right. Would you say the bow hole is drilled at a height position that only floods hull when rib is at rest and nothing happens when rib is at plane, angle issue.

Or it's a constant water in/water out issue ? BTW my drill is ready to make 2 big holes under my rib's hull...

Happy Boating

JamesF · 05 March 2013, 13:50

That's it exactly. The vents seem to come up above the surface of the water quite quickly (this picture is me landing one of ours; you can guess from the height of the bow that the holes are somewhere above the waterline — they're on the orange part — and that's with fuel, an anchor and a concrete weight up front). There's a small hole with a bung on the floor near the transom that drains into the flooding hull, and there's just air underneath when you look through it while planing (it's good for draining the last bit of water that won't go out through the elephant trunk).

How much gets into the hull while moving might depend on the exact boat too — our club has two, one quite a lot older and heavier than the other, and the lighter boat produces a small amount of spray that is uncannily directed forwards over the tubes before the wind catches it and blows it straight back in the helm's face; some of it might get in through the vents. I don't think the heavier one makes as much spray — it's certainly not as wet at the helm.

Pikey Dave · 05 March 2013, 17:49

Quote:

Originally Posted by Locozodiac

So at rib rest assume the hull fllods completely, once rib is underway water starts to exit through back vent hole, right. Would you say the bow hole is drilled at a height position that only floods hull when rib is at rest and nothing happens when rib is at plane, angle issue.

Or it's a constant water in/water out issue ? BTW my drill is ready to make 2 big holes under my rib's hull...

Happy Boating

The small holes are to allow air into the hull as the water drains from the stern, otherwise you would get a partial vacuum as the water tried to drain. The draining would be very slow without the vent holes.

JamesF · 05 March 2013, 17:55

It is agonisingly slow to drain without them. A minute or more instead of a few seconds.

tworotorturbo · 07 March 2013, 01:57

Ok I took her out for my first run today in some choppy water. I have to say that a RIB rides much better than a SIB. The existing 35 HP 2 stroke ran better than I thought. While cleaning, I removed a few screws from the deck that the previous owner used to install some scuba tank racks, and when at rest they acted as little geysers that let water into the boat.

Any advice on how to plug those up? I was thinking to just squeeze some epoxy in there.