QA Forgiving Hybrids

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Editor's Note: This is the latest in a weekly Q&A feature from GOLF CHANNEL's Chief Technical Advisor Frank Thomas. To submit a question for possible use in this column, email letsbefrank@franklygolf.com
 
Frank:
I started playing with stymies and no cleaning the ball on the green.
 
With cart trails and watering systems there have been a lot of changes in the rules, but I've never understood this: Why isnt a divot mark considered ground under repair?
--Wendell

 
Don Pooley
Don Pooley asks about trends in lengthening golf courses in 'Ask Frank,' Monday, June 25 at 11:00 p.m. ET on GC. (WireImage)
Wendell,
This is a question I discussed a few weeks ago and received lots of mail from some very passionate golfers! It is not an equipment question, but I am a golfer and in addition to writing many rules that relate to equipment Ive been peripherally involved in other rules-making issues. Based on this, I can assure you that the divot issue has been considered many times. I think the biggest question that needs to be answered is the same as the one the committees worry about when they consider allowing golfers to tamp down spike marks: How do you enforce it properly?
 
It is very hard to determine if a 'spike mark' is a spike mark. Before you know it, every blemish becomes a spike mark and golfers start tamping a path to the hole. This will not only alter the conditions you are faced with, but also take a lot of time ' and the last thing we need these days is to add time to a round of golf. When is a divot mark no longer a divot mark? At what stage in the healing process can we claim it is still a divot mark? Would it not be easier and fairer all round for everybody, if we allowed a golfer to roll the ball over anywhere on the fairway for every shot?
 
You can see where this would end up. I don't think it is fair to find your ball in a divot mark on the fairway or in a footprint in a bunker, but these are the breaks. The alternative in trying to make this fairer is too much of a change in the game. We play the course as we find it, and the game is not always fair.
 
I have decided to give you the opportunity to speak out. Click here to have your say and tell me whether you think that golfers should be given relief from a divot scar. Results will be published next week.
 
Frank
 
Frank,
Love your column and insight on the equipment Q's. Refreshing to hear an expert tell people the truth as oppose to what they want to hear!! My question is this: Why are clubs shafted with graphite longer than steel ones? I guess its because they are lighter, but wouldn't the benefit of added club head speed be offset by drop in accuracy for the average golfer?
 
Thanks,
--Glenn

 
Glenn,
There are a couple of reasons why a graphite-shafted club is longer than a steel-shafted club.
 
First, because the graphite shafts are lighter than steel shafts, the swing weight of the graphite-shafted club, all else being equal, will be several points lighter than the steel-shafted version. By taking the graphite-shafted club longer, the manufacturer doesnt have to change the head weight when shafting with graphite to maintain the same swing weight.
Swing weight seems to be sacrosanct, and manufacturers like to maintain swing weight for men at about D2. If the length is increased by about 1/2 an inch, this solves the swing weight problem ' though, as you note, it can create other problems for the golfer that are more important than maintaining swing weight.
 
Another but secondary reason to increase the length is that it will increase the head speed slightly, which will increase distance by about 5 yards or more. Anytime you can increase distance, it is good news for sales.
 
Yes, you will also decrease accuracy a little whenever you increase length, but most golfers prefer a few extra yards and will give up a little accuracy for the extra distance.
 
We are all the same, aren't we?
Frank
 
Frank,
How much more perimeter weighting/forgiveness can be designed into hybrid clubs than super-game-improvement irons? I understand how the lower center-of-gravity of hybrids enable them to launch a ball much higher than even a very forgiving long iron, but as ball trajectory and forgiveness are two different issues, how much more forgiving can a hybrid ultimately be?
 
Thank you,
--Christian

 
Christian,
Your question is about the forgiving difference between super game improvement irons and hybrids.
 
Forgiveness is a term used to describe the resistance to twisting of the club head at impact when you miss the sweet spot. Twisting decreases the efficiency of the impact in terms of both direction and ball speed.
 
To increase the 'forgiveness' and decrease the amount of twisting, manufacturers have created clubs with a higher MOI (moment of Inertia) by distributing the weight as far away from the center of gravity (c.g.) as possible. (See What is MOI?). This MOI is measured around an axis through the c.g. from the top of the club to the sole in most cases for irons.
 
Cavity back irons have the weight distributed toward the toe and heel, which provides toe and heel forgiveness. The sole weighting will lower the c.g., which is good, but the forgiveness up and down is not as good as it could be. To improve the up and down forgiveness, weight should be positioned both up and down away from the c.g. on the club head, increasing the MOI around a second axis through the toe and heel. Irons have a limited amount of room in which to distribute weight up and down, if at the same time you want a low c.g.
 
Another useful way to increase the MOI in the up and down direction is to move the c.g. backward, away from the face. To do this you need to increase the weight toward the back of the club head, as it is in wood clubs and mallet putters. Having weight in both the forward (face toe /heel) and back positions will do two things: it will allow you to lower the c.g. as in the case of the mallet putters or hybrids, and it will increase the forgiveness up and down on the face.
 
Drivers have a very high MOI (forgiveness) in the toe and heel direction as well as up and down because the c.g. is far back and the weight is distributed in the shell of a hollow spherical clubhead. To get the maximum spring-like effect, however, the face should be large with the c.g. close to the center.
 
Because fairway woods and hybrids are hit off the fairway in most cases and not off a tee, the c.g. has to be low and directly behind where the impact point is going to be on the club face, with the weight distributed as far as possible from the c.g. To do this most effectively, the shape should be more like a low profile fairway wood than a big faced spherical driver.
 
Because the c.g. is farther behind the face in a hybrid than in even the super game improvement irons and the weight is better distributed around the outside, it will be more forgiving in all directions than an iron club can be.
 
Sorry for such a drawn out answer, but I felt it necessary for you to understand the reason why, so I gave you a super-game improvement answer.
Hope this helps
Frank
 
Click to purchase the Frog PutterFrank Thomas, inventor of the graphite shaft, is founder of Frankly Golf, a company dedicated to Helping Golfers. Frank is Chief Technical Advisor to The Golf Channel and Golf Digest. He served as Technical Director of the USGA for 26 years and directed the development of the GHIN System and introduced the Stimpmeter to the world of golf. To email a question for possible use in an upcoming Let's Be Frank column, please email letsbefrank@franklygolf.com