THE UNSEAWORTHINESS OF SMALL CATAMARANS

F

FishExcutnr

Sealiner
blah blah blah. There are good boats and bad boats, some have twin hulls some have one hull. Some boats are ugly some are pretty. some are bad but have good skippers, other are good but have clueless skippers.

in the end most modern ski boats are pretty lekker. What counts is how many fish you catch off them!

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Ah here is some pretty fish pictures from yesterday, i feel like this FISHING forum has to much drovel and to little fish these days!

caught 22 yellowfin between 12 and 22 kg in 2 days, fished 2 up and 3 up. been sick. seen some marlin, got my first dorrie. Had fish on plugs, spinners, onde ondes, rooster poppers . epic.

Most importantly i learnt a shit house. Done just over 1400 nm on the new boat since may last year. lekka

caught fish on a Cat, could have been on a mono. doesent really matter now does it :SSS:SSS
 
T

thika

Sealiner
Can't argue with that!

Strange to see that Dorado down here

But your hot blue water is 5 miles off the point

Ours is 40 miles still

All set to go today, but mist thick since we woke up at 04h00 till now

Do you have a regular job?

:fbash:fbash
 
F

FishExcutnr

Sealiner
no regular job thika, no boss, no set hrs, no dependents and just enough money to fish fish fish, i'm off soon, leaving the country for a bit, so just fishing full time right now off cape town because it likely i wont be able to fish here again for a year or 3 and want to use the boat before it collects dust.
 
L

L Hooker

Senior Member
Hey Edgy I've owned 2 cat hull stingray inflatables been through insane surf and seas, they handle incredibly well. Enjoy your boat bud
 
F

Fin-S

Sealiner
I think the general idea of Thika's first post was to try and get us to consider how the different hulls react. He also very clearly stated small, narrow and low sponsons.

In this case, he is quite correct - a cat like so will not be as safe against a small foamy as will the same length mono - provided the mono has a sufficient hull depth.

When you consider the centre of flotation and the centre of gravity, I find it useful to consider very simple forms. The first is that of a simple marine weather bouy. It has a very heavy base that is submerged and that acts as a keel, and a low bouyant top. It will float over almost any wave and will surf in to the beach in an upwards position. Consider this as representative of an extreme deep vee. Heavy keel, sharp vee, narrow top but with good flotation.

Now consider a small shallow pontooned cat. It has a high centre of gravity with one centre of flotation that is in perpetual motion (in effect making two centres of flotation - one in each hull). The moment the cats lateral force (from a wave) outweighs its vertical force (from centre of flotation) it will move sideways, the one sponson will act as a resistor and the law of physics (equal and opposite) will occur where the other sponson will lift.

However, the very same thing will happen with a shallow vee. In this instance, a deep hulled cat with adequate mass will outperform a shallow hulled dam boat.

Compromises!
(And just to prove it, I flipped our Lifesaving duck last weekend on a 1m foamy that the surfers had ignored for being too small! - Its not all about the boat.
 
C

Carl P

New member
I note that most of the pics in the beginning were taken at the Launch at Sodwana.

I have been going to Sodwana as long as I can remember. I have personally recovered more mono hulls from the surf at sodwana that flipped than cats.

A particular case was a mono that came in to beach one morning called withc doctor, a foamy lifted up the transom in the shore dump the boat turned side ways and was gone instantly in 500mm of water!
 
B

benniejordaan

Sealiner
sea sick wrote:
it's still good to know, what to avoid.
maybe its about the size that counts................
Click to expand...
No, I think it's about how you skipper a boat.
Bigger boats go out in bigger surf. Same problem if you make bad decisions. Monohulls also fall over if you put them in that position.
 
W

willem wikkel spies

Moderator
Staff member
benniejordaan wrote:
sea sick wrote:
it's still good to know, what to avoid.
maybe its about the size that counts................
Click to expand...
No, I think it's about how you skipper a boat.
Bigger boats go out in bigger surf. Same problem if you make bad decisions. Monohulls also fall over if you put them in that position.
Click to expand...
interesting Bennie

hense my topic a while back, is bigger better?

 

back on topic;

as young skippers we need to know these things. you guys down there have the sea to your self, en ons suig maar aan die agter speen.

 

now, the pics thika posted, were these boats cruising, speeding?

just thinking, when on the plane, how would the boat react differently then it was "standing still,slowly moving" when getting such a wave beam on?
 
B

benniejordaan

Sealiner
sea sick wrote:
benniejordaan wrote:
sea sick wrote:
it's still good to know, what to avoid.
maybe its about the size that counts................
Click to expand...
No, I think it's about how you skipper a boat.
Bigger boats go out in bigger surf. Same problem if you make bad decisions. Monohulls also fall over if you put them in that position.
Click to expand...
interesting Bennie

hense my topic a while back, is bigger better?

 

back on topic;

as young skippers we need to know these things. you guys down there have the sea to your self, en ons suig maar aan die agter speen.

 

now, the pics thika posted, were these boats cruising, speeding?

just thinking, when on the plane, how would the boat react differently then it was "standing still,slowly moving" when getting such a wave beam on?
Click to expand...
It would be worse on the plane.

I have seen a monohull flip over in a shore break just like it happens with Cats.
I have also seen good transkei skippers "chug" out in in big seas with small boats. Not even timing it. They go out and keep turning till it's flat. Before you know it, they are out.

In the pics poster, those skipper should not have been in that position in the first place. At least make sure you are at right angle or even better at a slight angle. This applies to any boat.
 
T

thika

Sealiner
Sea Sic

It gets worse at speed

These guys were on the plane on their way to beach

The video:

Starts at 1min 23 sec...note the guy going overboard

http://www.youtube.com/watch?v=RWoycbDCeog
 
T

thika

Sealiner
And here is the sequence of events of the other boat (happened in Mozambique)

Note the two crew going overboard one after the other)

T answer you, I reckon hit anything that jumps at you at a slight angle if there is time...anything better than broadside on

@ BTW, I don't think these guys were amateur skippers or in the wrong place... they were fishing compo's and coming in, following the line to beach the boat....through the backline already and the surf was not too huge...what happened was totally unexpected and all on board were caught out

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