if you only have a 10 foot length for them to climb, they'll reach the top and continue to grow until they get too heavy to support themselves. at this point, the weight of the excess growth will bend them down, but the growing tip will continue to try to grow upwards, wrap around itself and continue this cycle until it's harvest time. the only problem is that it creates a tangled mess at the top of the structure and is very hard to pick. an english researcher wrote a book which included an experiment where the researchers were trying to see what happens when you grow them on an angle. the conclusion was that 65 degrees from horizontal was the best for production. they also stated that different varieties performed better at different angles(long and involved explanation so i won't go into it). the whole idea is that they want to grow straight up but will grow at less than a 90 degree angle from horizontal with so varying degrees of success.