Can anyone please explain the difference for me.

None
They are two words for the same thing

The one I have says "booster" on the sail bag.

I'd be inclined to say a gennaker is a cruising sail usually designed to go into a snuffer or sock but an Assy is a racing sail but hey, it's a pretty marginal description of the difference.

Thanks.
Found this on North Sails after a bit of searching: www.northsails.com/sailing/en/sails/types

So an Asym is not a Gennaker. However a Gennaker is an Asym.

Hi Valo,
My two chutes are labelled gennaker and spinnaker.
The gennaker is our reaching kite, uses a wire luff and is a crossover headsail/spinnaker. It goes off the bowsprit, not the forestay and uses the spinnaker sheet blocks at the back of the boat, so its rated as a kite. We can hold it up to about 70 TWA in light airs, and if its really blowing we can run it effectively down to about 150 TWA, in light to medium airs you get rid of it at 120TWA. Great sail, indestructible and by far my favourite. It's the smallest at 100m2.
If you're three sail reaching, it's the gennaker as the kite and the staysail, the luffs are the same angle.

The spinnaker is an asymmetrical VMC deep running sail , bigger, and loose luffed on a tack line to the bowsprit with much broader shoulders. This is for 110-160TWA. Much better for running deep as you can ease the tackline and get the shoulder to windward of the forestay, something the gennaker will never do. It's a bit bigger than the gennaker at 150m2.

Cheers,
SB

They are pretty much generic terms that can be used to describe each or both. An asymmetric is any spinnaker that is not symmetrical, obviously.
Gennaker is a cross between Genoa and spinnaker and is asymmetrical as a result.
So can describe any asymmetrical downwind or reaching sail that is not a true headsail.
confusing isn't it?

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shaggybaxter said..
Hi Valo,
My two chutes are labelled gennaker and spinnaker.
The gennaker is our reaching kite, uses a wire luff and is a crossover headsail/spinnaker. It goes off the bowsprit, not the forestay and uses the spinnaker sheet blocks at the back of the boat, so its rated as a kite. We can hold it up to about 70 TWA in light airs, and if its really blowing we can run it effectively down to about 150 TWA, in light to medium airs you get rid of it at 120TWA. Great sail, indestructible and by far my favourite. It's the smallest at 100m2.
If you're three sail reaching, it's the gennaker as the kite and the staysail, the luffs are the same angle.

The spinnaker is an asymmetrical VMC deep running sail , bigger, and loose luffed on a tack line to the bowsprit with much broader shoulders. This is for 110-160TWA. Much better for running deep as you can ease the tackline and get the shoulder to windward of the forestay, something the gennaker will never do. It's a bit bigger than the gennaker at 150m2.

Cheers,
SB

Thanks Shaggy.
I just looked up TWA. Learn't something new again.
I think from 100sqm to 150sqm is a bit more than slightly bigger.

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Galatea said..
They are pretty much generic terms that can be used to describe each or both. An asymmetric is any spinnaker that is not symmetrical, obviously.
Gennaker is a cross between Genoa and spinnaker and is asymmetrical as a result.
So can describe any asymmetrical downwind or reaching sail that is not a true headsail.
confusing isn't it?

YEP!

The term Assymetric came out of Skiffs (18s) whereas the term Gennaker came from Keelboats (Genoa/Spinnaker)
Assymetrics were for sailing apparent wind angles to advantage along with simplifying the gear, while Gennakers I suggest we're more about making sail handling easier.
Not until Keelboats became light enough/the right shapes would carrying such a sail be advantageous.
I recall Australia IV using a Gennaker in the final stages of the 87 America's Cup defender races to some effect...mostly due to its massive area, but it was not usable on the runs.
Forget the sailmaker double talk....call it what you want I reckon.

Just make sure that when buying a boat and they say it has a gennaker they know what they are talking about.
I bought mine from an inexperienced person who only used the boat for a short period as the boss said NO.
He said as well as a main and jib it had a gennaker and spinnaker but he had never used them which I accepted due to his inexperience.
What I got was an old sym spin. No pole and a number two Genoa.

Should we also throw a Code '0' into the mix? Just to make it more confusing.

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Jode5 said..
Should we also throw a Code '0' into the mix? Just to make it more confusing.

Oh hell don't even go there . What about a screecher aren't they both gennakers which are reaching assys OR are they big colourful genoas.
sym spin and a blooper solves everything KISS

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Jode5 said..
Should we also throw a Code '0' into the mix? Just to make it more confusing.

Please no

We forgot Jib top...have to chuck them in there as well.
Why have you got a bimini Jode? That almost reaches the back of the boat, shade for everyone!
That's my next sail, a go to windward Code 0.
Yum.

Bring back the Blooper!

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Jode5 said..
Should we also throw a Code '0' into the mix? Just to make it more confusing.

Is it sheeted through a block on the boat behind you ??????

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shaggybaxter said..
We forgot Jib top...have to chuck them in there as well.
Why have you got a bimini Jode? That almost reaches the back of the boat, shade for everyone!
That's my next sail, a go to windward Code 0.
Yum.

It's an awesome sail when just cracker and under 15 kn. Hair is getting thin, so need the Bimini.

Screecher tends to be a multi hull term for code 0.
As for keel boats flying off a sprit, you have the following.
J0 - same size as a #1 h head sail, flown when beam reaching in higher winds
FR0 - fractional code 0. Usually higher wind strengths than the code zero and closer to the breeze
Code 0 - usually masthead and lighter breeze TWA 50-130deg depending on the breeze and boat

Then you have the range of assymetrics from A1 through to A7, with the common ones being the A2 for VMG running l, A4 for heavy running and A5 for heavy reaching.
A7 is usually out of a laminate cloth while the rest are normally nylon

My mate has a 28ft sailing cat and we wanted a bigger front sail and all the various terms came out which can be a bit confusing. Ended up calling it code zero.
We have had it out a few times and it's a game changer.
I used to sail on Greg Young 6.5m "Raging Bull" and also the Bull 7m and pivoting bowsprit with asymmetric kite.
From that experience, the cat's bowsprit is a cut down pole that we can change the angle for downwind.