Fastest dinghy?

Originally posted by Chris 249

420s only lasting a season?? Cheez, back when I was a lad (a long time
ago) we had a Roga 420 that had done two worlds before we got it, and
it was still fast enough for my brother to get second in the Nationals (first Youth) and
to win states against guys who were 3rd in 420 worlds, two time Moth
world champs etc. 

I think I was talking to the brother of the world 470 and 420 champ
almost exactly a year back and he reckoned the 420 was lasting well.

We actually found the undercanvassed old girl would do the Cherubs in a
big, big breeze, but as far as going as quick as an 18' skiff or
12.......no chance. Not a single, solitary, tiny chance in any
practical conditions AFAIK.

If the "small dinghies are fastest" idea worked, perhaps the fastest of
all would be an old Scow Moth - vastly lighter than a 405 or 420, dead
flat, dead easy to sail, efficient rig, hull weight of about 25 kg,
wings.  But the Scow Moth cannot beat a big skiff. Maybe a
Contender -
long and skinny, designed to perform in wind - would be fast. But I've
never seen anything to indicate that a
Contender can beat a big skiff; we are very competitive with Contenders
in a Tasar and a Tasar (a good high-wind boat) cannot beat a big skiff
in terms of top speed.

The 420 is almost certainly not as quick in a big. big breeze as the 11'  VJ, which is
almost dead flat on the bottom, has twin hiking planks like a Canoe, a
small low-aspect rig, a skinny hull, and is designed to go fast in a
breeze. But the VJ doesn't beat skiffs.

The Skate is a 14' VJ, with an 11' long plank for the crew. Can you
imagine the leverage he's got? The skipper also has a plank. But
beating an 18? Dunno, the Skaters reckon they out-reach the I-14s and
16s, but neither 14 or 16 can beat an 18.

You'd get better power ratios in a Flying Ant,. probably (10'6" version
of a Cherub) than a 420, but would a Flying Ant beat an 18???? I
somewhat doubt it.

Have any of you who reckon a 420 could even look at an 18 ever
sailed an 18? Do the rough calcs on the power to sail area ratio, which
have
already been posted here. The 18 has much more power. The 18's hull
shape is designed to be efficient at much higher speed; that's one of
the reasons they have chines (the chines are there largely to keep the
boat tracking at extreme speeds). 420 hulls aren't.

18s and other skiffs are designed to lift entirely out of the water and land, without losing control. 420s aren't.

Skiffs are designed to go fast when heeled, which is inevitable in a big breeze. 420s aren't.

The Laser is faster than the 420 normally, the Radial is faster than
the big rig Laser in a strong wind, but it's a joke to think that a
Radial will out-speed an 18 in any conditions.

I'm not saying I'm sure the 18 will survive higher winds than the 420,
but it will go much faster in 25 + knots than the 420 will go in 50.

There's a possible analogy with windsurfers. The Formula boards (fat,
but only 8' long) have to stop racing in conditions when the longer
raceboards (12' long) can still get around the course - because the
short, fat idea doesn't always work.

But the windsurfer analogy isn't much good generally. Boards just feel
different, they work differently. I've heard all the supposed reasons
and I still disagree with most of them (and I have some very good
support for my disagreement). But it's noticeable that windsurfer
dynamics are generally very different from boat dynamics. Things that
work on windsurfers don't work on boats, and vice versa.

I'm not knocking the 420, which is a good boat; but the fastest dinghy????

Edited by Chris 249