Re: Reasons To Be Grumpy thread

[Siz]

fascinating

Got in a tangle while baring away and resetting

what does ^^this mean?

Got in a tangle = exactly as it sounds - got tangled up in my ropes.
Baring away = turning from an upwind heading to a more downwind heading. Boat is much less stable when travelling in the same direction as the wind. The transition during baring away can be dicey in a blow.
Resetting = adjusting the sail settings to make more efficient use of the new direction of wind incident on the sail. (mainsheet (adjusts angle of bottom of sail relative to wind), kicker (tightens the sail leech, increases mast bend, reduces sail twist at top of sail) cunningham (flattens the sail luff), outhaul (flattens the sail foot) and centreboard (keeps boat in a straight line, but sometimes just causes drag) need to be adjusted).

Sounds impressive, probably, but the reason I'm not a great sailor is that I don't fully understand the interrelationships between all of these settings in relation to wind direction, wind speed, my weight, body position, sail design, draft characteristics, pitch and roll angles etc...). I can follow the fundamentals and that keeps me in the game, at least.

[billy rubin]

changing the shape of the aerofoil is an intriguing skill. in an aeroplane its fixed, all you can do is mess with the flaps, and thats a low speed thing.

but on a boat its all up to you. amazing.

do hi tech yacht racers use wind tunnelz to dezign their boats?

[Siz]

changing the shape of the aerofoil is an intriguing skill. in an aeroplane its fixed, all you can do is mess with the flaps, and thats a low speed thing.

but on a boat its all up to you. amazing.

do hi tech yacht racers use wind tunnelz to dezign their boats?

Mostly done with computer simulation these days. No expense spared though - these things are spacecraft!
Check out the new AC75 design for the 2021 America's Cup. Solid sail, foiling monohull yachts:

However, this below is the pinacle of racing for me - 18ft skiffs:

[Bad Penny II]

changing the shape of the aerofoil is an intriguing skill. in an aeroplane its fixed, all you can do is mess with the flaps, and thats a low speed thing.

but on a boat its all up to you. amazing.

do hi tech yacht racers use wind tunnelz to dezign their boats?

Mostly done with computer simulation these days. No expense spared though - these things are spacecraft!
Check out the new AC75 design for the 2021 America's Cup. Solid sail, foiling monohull yachts:

However, this below is the pinacle of racing for me - 18ft skiffs:

Yes well, all this isn't for you now, is it?
Have you considered taking up knitting?

[Siz]

Yes well, all this isn't for you now, is it?
Have you considered taking up knitting?

Ouch. Truth hurts, Dude!
I always fancied the idea of green bowling when I'm too infirm to do anything fun. Past that, I'd never given thought to a seated activity. P'haps spend more quality time with my tropical fish???
Knitting isn't out of the question...

[billy rubin]

that skiff stuff looks fucking dangerous, if you dont mind me saying so.

what doez the hull of your boat look like? these skiffs seem to be cut off square at the rear, although i cant make out the shape at the water. a square back might or might not cause a low pressure zone that would slow the boat, depending on the angle of closure. motorcyclez have a serious problem there.

are the shapes rwquired to be tge same by the rulez?

is there a thread here about your boat? i have queztionz

[Siz]

that skiff stuff looks fucking dangerous, if you dont mind me saying so.

what doez the hull of your boat look like? these skiffs seem to be cut off square at the rear, although i cant make out the shape at the water. a square back might or might not cause a low pressure zone that would slow the boat, depending on the angle of closure. motorcyclez have a serious problem there.

are the shapes rwquired to be tge same by the rulez?

is there a thread here about your boat? i have queztionz

Nah, not really dangerous. Just difficult to get right without falling over.

Does this answer your question? (not me BTW, just same class of boat) The transom is completely open with no lip. Shape-wise, just a smaller version of the 18ft skiff:



This is a one-design boat. There is a single mould from which ALL class-compliant boats must be formed (currently owned by Hartley Boats, but originally owned (and designed) by Topper). Even the sail has to be made by one particular company (North Sails). And there are strict rules about where and how any fixings are made to the hull.

[jumbojak]

Sciz, would you be deeply offended if I told you I read all your posts in a Yorkshire accent?

[Siz]

Sciz, would you be deeply offended if I told you I read all your posts in a Yorkshire accent?

ROFL. Would that voice also be female, by any chance...??? 

Anywhere between Daniel Craig and Ricky Gervais (depending on who I'm talking to) would be nearer the mark.

You're all George Peppard to me...

[billy rubin]

Nah, not really dangerous. Just difficult to get right without falling over.

Does this answer your question? (not me BTW, just same class of boat) The transom is completely open with no lip. Shape-wise, just a smaller version of the 18ft skiff:

This is a one-design boat. There is a single mould from which ALL class-compliant boats must be formed (currently owned by Hartley Boats, but originally owned (and designed) by Topper). Even the sail has to be made by one particular company (North Sails). And there are strict rules about where and how any fixings are made to the hull.

so the stern lookslike this?


so the boat is basically a wedge, but the bottom is rounded so that the waterline around the stern assumes an ellipse? in spite of the square transom. nd the front will be an ellipse as well, because the bow is tapered and maybe even out of the water. your picture shows pretty clear laminar flow slipping out from under the stern, so low drag.

is this a decent cross section?



what are you allowed to change? can you mess with ballast to change the area and the shape of the contact between the hull and the water?

what's it called? topper has all sorts of hulls on the net.

[Siz]

Ah, a laser 4000. Nice quick boat, but, like Topper-designed boats (apart from THE Topper) have lost popualrity in recent years to the RS fleet (in the UK at least).

My boat is a Blaze. My son co-owns a Buzz (also originally Topper). I also used to Race the ISO (big brother to the Buzz).

Almost all modern racing dinghy hulls these days look like this.

Ballast is pretty irelevant in dinghys unless for very light people trying to achieve more weight as righting moment (subject to an upper limit set by class). The water contact area is one of the 'settings' that one tunes with one's body. Move forward in light winds to raise the fat stern out of the water (creating the oval-shaped contact area), or move more aft in strong winds to encourage planing on the flat rear portion (not eliptical).
Re laminar flow: I have limited knowledge of the concept. I just know that the boats of this design are the fastest on the dighy circuit.

From your blue image, Ian Howlett co-designed all of the 'modern' Topper boats. John Caig, Howletts design partner, is member of my club's alumni.

WRT what you can change - lots and not much! The one-design concept is used to create an even field so that the rich aren't advantaged.

[jumbojak]

Sciz, would you be deeply offended if I told you I read all your posts in a Yorkshire accent?

ROFL. Would that voice also be female, by any chance...??? 

Anywhere between Daniel Craig and Ricky Gervais (depending on who I'm talking to) would be nearer the mark.

You're all George Peppard to me...

Female? No, but I can make adjustments.

[billy rubin]

Ah, a laser 4000. Nice quick boat, but, like Topper-designed boats (apart from THE Topper) have lost popualrity in recent years to the RS fleet (in the UK at least).

My boat is a Blaze. My son co-owns a Buzz (also originally Topper). I also used to Race the ISO (big brother to the Buzz).

Almost all modern racing dinghy hulls these days look like this.

Ballast is pretty irelevant in dinghys unless for very light people trying to achieve more weight as righting moment (subject to an upper limit set by class). The water contact area is one of the 'settings' that one tunes with one's body. Move forward in light winds to raise the fat stern out of the water (creating the oval-shaped contact area), or move more aft in strong winds to encourage planing on the flat rear portion (not eliptical).
Re laminar flow: I have limited knowledge of the concept. I just know that the boats of this design are the fastest on the dighy circuit.

From your blue image, Ian Howlett co-designed all of the 'modern' Topper boats. John Caig, Howletts design partner, is member of my club's alumni.

WRT what you can change - lots and not much! The one-design concept is used to create an even field so that the rich aren't advantaged.

the water contact thing is something i was unaware of, in that you can switch between a minimal oval shape water contact area to presumeably a smaller, what, parabola? when planing.

glen curtis invented a cutoff to the rear of his floatplane pontoons to reduce hydrodynamic drag. he found that he couldn't get the planes into the air. apparently the pilot tipps the plane back and planes on the rear, while lessening the overall contact to reduce hydrodynamic drag.



it looks like a stepped hull is used in planing on speedboats. are there sailboats in your size class that use these?

[Siz]

Nope. Never seen or heard of anything like that.

Is there an image missing in your post? I only see 1. Can you edit?

[billy rubin]

they both show up for me