Pepper Spray. I ALWAYS have a can on me, no matter what the local laws.

I was at a school playground about a year or so ago and a dog (German Shephard/Lab Mix it looked like) came up out of nowhere and headed straight for my wife, and 14 month old daughter. It was barking furiously, snarling, teeth bared and lunging forward. The kids were screaming, my wife was screaming, and I was yelling and waving my arms, but the dog would not back down and started to move forward. I got between wife and kid, my son ran into the van, and I sprayed the *&^*&^ing dog with a whole can of pepper spray, right in the eyes and nose I would have shot it too, if I had my gun in the car, but then again we were on school grounds and I imagined that it would have been a Big Issue.

The dog was effectively blind except for sensing light and shadow and snapping at any motion at this point, so my wife and kids got into the van while I looked around for a large stick to club the damn thing to death. Unfortunately, I wasn't able to find a big stick, but I did try to run it down with the van as we left, but it was in between some cars by that time. I called the school Monday to let them know about the vicious dog on the grounds and they said that they knew about it, but they didn't want to do anything about it - they said when the dog comes, the teachers tell the kids to run away. Duh.

Anyway, pepper spray made a good stop, I HIGHLY reccomend that people carry some AT ALL TIMES. The only time this does not apply is flying, even in checked luggage (even though it's allowed) because a burst pepper spray canister would make the cabin very unconforatble.

I'd suggest you get a lawyer, and get that Ridgeback put down. that's a dangerous animal and should not be out in the public. I have no tolerance for dangerous animals of any kind.

I've owned large dogs and medium sized dogs - the mediums were Pits or in the family of Pits (AmStaffs, American Bull Dogs) so people have a certain reaction to them without the dogs ever acting agressive in the first place. I never let my dogs run where there are people around. At the first sign that a person has arrived - the leashes go on. I trust my dogs, but one can never tell, and they may interpret something as an attack that isn't.

You might consider mace - like postal delivery people carry. If someone has their dog off leash and the dog is charging you - to my mind they can hardly complain if you defend yourself in a non-lethal manner. Better that than you getting bit and the dog getting the blue juice.

Speaking of attatching leashes quickly - REI used to sell a collar that had a short leash attatched that wrapped around the collar and secured to itself (to keep from hanging) with velcro. It's not good for walking - but it makes a good emergency leash - when you didn't expect to need one, but here come people / another dog... I had one and have used it for that purpose and it worked out well.

Dog Collar

I realise I wasnt there and you were focused on your dog, but if the ridgeback turned on you at any stage, the first thing you need is your hand covering your throat. Thats the first place a dog will attack if it means business.
Here in Australia, where dogs are likely to come into contact with wild pigs or kangaroos, they use wide leather collars the protect the dogs throat. maybe you could invest in something to protect your dog.
As for other means of protection, start with a heavy stick, but knowing ridgebacks you could hit one across the back of its head with full force and it would barely know you are there.
Available over here is an electronic sounding device designed to hurt a dogs hearing. These are marketed to stop dog attacks and video footage I've seen shows a dog in full attack mode stop instantly. Might hurt your dog in the process, but both dogs wont be looking at each other after you press the button, and they will survive.
Another cheaper alternative would be to fill a small water pistol, something like the small Super Soaker range, with citronella. Dogs seem to hate it. With the range of those water pistols you could give the aproaching dog a dose in the face before it had a chance to bite.
And you can also try yelling at the other dog at the top of your voice as if you are the one in control.(full scream might be a better description)
The idea being to confuse the other dog, so use standard dog control type commands. "Sit Down and shut up" would be the first thing coming out of my mouth. Ive made guard dogs back down that have charged up to a fence by yelling back at them. If they think they are doing wrong or if you make them think that, they soon back off. Mind you I wouldnt have tested it without the fence being there <img src="/images/graemlins/smile.gif" alt="" />

Yeah, my dad was a postman for 20+years, and he always used this funny helmet when he was riding the motor scooters. i found out why one day, when he came home from work and told me about this new dog on his route that attacked. This helmet sat on his head, not like modern helmets which fit around the head, and he had a quick release button on the strap. As he was riding the dog ran up and as it was about to bite his leg, Dad had grabbed the quick release and swung the helmet down and layed the dog out cold. That dog wouldnt go near him after that.

He taught me to deal with agressive dogs.
When I was at high school some of my friends told me aboutt a dog in a wrecking yard and how mean it was,So we walked past the 6 foot high fence. They wouldnt go near the fence but I walked up close and when the dog ran up and started I turned towards it and acted as if I knew it and called it over as if to play with it and wanted a game. That confused the hell out of it and I even got to give it a quick pat through the fence.
Its all in the bluff.

I think that might be an overreaction. I generally agree that any dog who bites a person without provocation should be put down. However, in this case: (1) they were in a place where people agree not to use leashes and (2) he didn't let go of his dog's collar when the other dog charged. I would humbly suggest this was a mistake on the part of the original poster and I wouldn't necessarily blame the dog for it.

Dogs go for each other's throats. If you've ever seen a large dog grab another one around the neck and do the "shake of death," you quickly learn not to get your hands involved in that. Most of us who keep large dogs learn how to manage this kind of situation without getting bitten. I'm sure this sounds barbaric but dogs will be dogs. They will bite each other and if you put your hands in there, you're guaranteed to get bitten too. This applies even to good, trained dogs; even the best of them can be unpredictable and it's the responsibility of the owner to learn how to manage it, which is why I think pteron asked this question in the first place. I think it's great that he wants to figure out how to deal with this, without saying the dog should be put down, etc.

My $.02.

My dad has been bit by loose dogs a few times. Once he took the brunt of an attacking large dog to save our cocker spaniel from harm (she was leashed). He picked her up (an option I don't think you have, given your large dog), but not in time to save his leg from a nasty bite. Rabies shots are not fun.

When facing an irresponsible owner, who is really the root of the problem, there is not much you can do before an incident. It's not too much fun to keep dogs on a leash when they want to run, but at least you wouldn't be contributing to the problem of loose dogs.

I've always lived sorrounded by dogs. I love big breeds but I take their trainning very seriously, I'm not going to be one of those idiots who can't control their dog and give the whole breed a bad name. I hate hurting them, even when they attack me (weird for a guy who hunts for a living, isn't it?).

In the city I have a really large Mastiff (he weighs 100kg, around 200 pounds) a young Pit Bull and a ridiculously small mixed breed dog that just walked into my yard a couple of years ago (watching him play with the mastiff is great). Al my dogs are very friendly, they are used to other dogs and people (I try to make them play with kids as often as possible). The mastiff has a lot of training as a rescue dog. Since I usually walk them together with a friend who has six labs (also rescue dogs) I haven't had many problems with other dogs, since they tend to stay away from a tight knit group like this one.

Anyway, the only problems I've had were with owners too stupid to keep an eye on their dogs and dog walkers who just sit down at the park with their headphones and let their dogs loose. I'm proud to say that my dogs never started a fight and in many years I only had a nasty incident. There was a doberman trying to attack my smaller dog and my mastiff stood infront of him, looking at me and waitting for permission to help his little buddy. I put both of my dogs on leashes and shouted to the dog walker who was sitting down under a tree listening to music, oblivious to what was happening. Things got out of control when the doberman finally attacked the my little dog and my mastiff went berserk. I pulled off the small dog, but I wasn't able to separate the other two (plus the little one kept trying to get back in). The poor doberman got really mangled (thank God it wasn't killed and a veterinary friend of mine had his office right across the street). When everything was over the idiotic dog walker came running and threatening me to call the police because of what my dog had done. I didn't let him finish the sentence before I kicked his ass, I was so pissed of that this idiot had gotten the animals hurt (not just mine, I can't stand the sight of a wounded dog). He tried to press charges for assault, but since the park was a block away from my home lots of neighbours who know I'm not an agressive person and whose kids play soccer with my dogs told the police what happened and I didn't even have to go to the police station.

In the mountains or in the countryside dogs are a bit more of a problem. Sometimes they'll come out of a field just running at you. I think a good, thick, walking stick is an excelent defense. If I was with kids and thought there was real danger, I would act like with a mountain lion or wild boar: fill it up with lead. Extendable batons can be a good choice for urban dog attacks. I know I could take out almost any dog with my knife, but I would probably get hurt badly in the process. Heavy boots are another good thing.

In the city I find that the problems are usually the owners. People don't assume the responsability that comes with owning a dog and the poor critters get hurt because of the overpopulation of idiots.

Big sticks work!! I do not walk my dogs with out at least a hickory cane or more likely a staff. My normal walking stick is about nose high on me and gives me enough reach to ward them off if they are just curious or lots of stick to work them over with if it comes to that. They are usually intent on my dogs and never see the stick coming. I have swatted their legs out from under them, driven the end of the stick into them, as well as just plan old hit them across the back or head. I have spent many hours working with my dogs to try to ensure they don’t cause problems and take what precautions I can to keep the irresponsible at bay.
The English have a history with the quarter staff might be time to knock the rust off of some of those old techniques.

P.S. No hope of putting the other owner down I guess? Since they are the problem not the dog that is the most logical answer.

I've been lunged at a few times, I found that having a firm grip on your dogs collar allows you to use him as leverage: pull back hard on your dog as you pivot at the hips, lift your foot up and kick the attacking mutt under the chin as he lunges. I've done it twice and stunned the attacker into retreat. It even surprised my dog so much he also stands down.

If you separate fighting dogs, seize the hind legs and pull hard. They will let go with their jaws and turn on you. Let you foot be convincing…

I carry pepper spray (dog repellent), used it once, it works, you will get a mouthful yourself and you need time to pull it out.