Coastal seaworthiness

[Martin]

I've just been looking at the hull following Donny's post, i hadn't realised its a completely different design to the normal f-ribs.
Now I'm no sailor lol, but looking at the bow, it matches the design you see on a sail boat, a very pointed nose (bow) to cut through the water at slow speeds.. A large amount of the hull is in the water but with a knife like cut at slower speeds.

Take the speed up and the bow lifts-the boat jumps "on the plane" and the clever hull design further aft switches to a more suitable design for a power boat.
I'm probably talking nonsense but looking at it as a mechanical engineers view rather than a frib powered nutter out of a truck.

f-rib 460

FRIB 460

frib 460.jpeg (10.07 KiB) Viewed 4217 times

I personally think your going to be pleasantly surprised, I do hope i'm right



More to the point.....
Get it wet with the outboard on and have some fun

[The Gurnard]

Yup..its what perhaps I would describe as a small semi planing hull ? .. and its not really comparable to a planing hull.

Plenty of info on the net with descriptions of the characteristics of the three main hull types..eg displacement.. semi planing..and planning.

Its also a bit like a bar stool with three legs instead of four..which is why I mentioned it may or may not rock a bit more when stationary. The Dory was and still is a very popular boat because its flat front was very stable for fishing.

But like I mentioned ..every hull has advantages and drawbacks.. and if I was after a sailing / come powerboat that folded ..you have the perfect boat

[DrHair]

All good info:
It does look like the bow cuts through well but yes, the spray can blow back in more easily. On the video, they must have at least four up and only a 9.9hp so more displacement than planing. However, with only two onboard, then the weight distribution may be further back onto the planing section of the hull. In a sense, once on the plane, the planing section of the hull is probably just the same as the 360 (as Martin says, the extra 1m doesn't count as it will be out of the water).

In fact, the next video after the one Paul linked to, shows the 460 S on the plane, two up with a 9.8 - at about 8 mins
https://www.youtube.com/watch?v=6rCqrJ_7n5Q
Two quite beefy blokes as well...
PS - I've started my review of the 460 S in the review section but can't seem to get the pics in the right order...

[DrHair]

One other question: I've pumped it up in preparation since it has been left folded up in my garage over winter, just to check no issues with it. But I can't seem to get the tubes very hard and when I remove the foot pump, it allows air to escape. The valves appear to be similar to my previous SIB which were spring loaded to close but I can't seem to get the Frib's to do that. What am I doing wrong? Or do I need an electric pump?

[Paul]

One other question: I've pumped it up in preparation since it has been left folded up in my garage over winter, just to check no issues with it. But I can't seem to get the tubes very hard and when I remove the foot pump, it allows air to escape. The valves appear to be similar to my previous SIB which were spring loaded to close but I can't seem to get the Frib's to do that. What am I doing wrong? Or do I need an electric pump?

Give the head of the valve a twist to take it off the cam to allow the spring to push the valve shut preventing air escaping.
Do the reverse to allow the air to escape during deflation when folding the boat up.

[DrHair]

Problem is, I thought I had done that!
I'll look again.

[Martin]

The valves can be a little misleading..
you'll hopefully find another little turn will allow the valve thumb end to exit a little more.

easiest way to do pics is do your typing, press enter..

Install image,(choose file, then add file)
put cursor on the line you want the pic, and click place inline.
Easiest if you name each pic with something relevant to your sentence.

It'll show something like [.attachment=o]img_2646.jpg[/attachment]

Click enter, do more writing and repeat....

Im more than happy to edit for you if required

EDIT.....
ALL FIXED FOR YOU NOW Dr.Hair

[DrHair]

Many thanks, will update the review once I've been out in it.

[Cliff]

[quote="Martin"]I have little or no experience compared to the chaps that have answered you, I do however have an f-rib 375.
Whilst not as long or broad as yours,

it's not the size that counts, it's what you do with it, or so my wife reassures me when I'm crying myself to sleep

[Si Crowe]

My 460 Frib has a long, slimmer profile compared to most ribs, which usually have blunt bows.
The actual width is greater than the smaller Fribs but doesn't look like it because of the shape.
My question is this: will I get a wetter ride when on the plane, especially in a Solent chop and
Would it make it less seaworthy?
I realise they all have a category C rating but just wonder if the shape will make a difference?
Also, it means I'll have to make my own bespoke bow dodger!
I hope to have a first hand answer to share in the next fee weeks...

In my experience a long skinny hull deals better in head seas as its can cut through better, less slamming than a beamy hull. however, the wet ride is more down to how effective the bow and spary rails are are at scattering the water away from the hull. the shape of the hull (especially at the bow) is critical to how a vessel cuts through the waves but a true deep V hull with a constant deadrise will cut better than a modified V with a flatter V at the transom. the biggest issue you would have in a 4.6m folding rib over a 4.6 "rigid" rib is flex at the joins and because of that i wouldn't treat the 4.6 f-rib any different to a 3.2m f-rib in that situation.