Throughout the summer in Canada, most of the lawn bowling rinks that I play on are less well maintained than those in Australia or Portugal. This is not surprising. These latter places don’t have a freezing winter to contend with. Whatever.
On some rinks the two meters closest to the ditches slopes off towards these edges by so much that a bowl that arrives near them almost inevitably continues on into the ditch. An observant team should not ask a lead to deliver jacks to within 4 meters of such front ditches. The reason: better players are more likely than poorer ones to deliver bowls behind the jack and if the jack is close to the front ditch such bowls will be lost.
In utter contrast to the above, there are other rinks that have somewhat of a physical barrier at one and sometimes both ends. Sometimes this is a thin strip of longer grass. Sometimes it is a raised strip of carpet on an older synthetic green. Sometimes it is an actual strip of wood or metal intended to support the grass but which over time has become higher than the playing surface as a whole. This lip on a rink is usually higher at some places than others.
This lip at the edge of the ditch can be used to improve your control of your team’s preferred jack length. Move the mat up the green so that the distance from the front edge of the mat to the two meter line at the front ditch is precisely what you would like. Then, bowl the jack, aiming it so that if it is long it will encounter this lip at the front ditch. So long as your deliver is at or past the two meter mark and so long as your delivery is not so strong that it jumps over the lip into the gutter, you will end up with the exact length you want once the jack is re-spotted on the T as the rules require. The protruding lip at the area of the ditch where you have aimed gives your team a reduced likelihood of losing the jack and a correspondingly increased chance to get your most preferred length!