Split loan simply put means to cut your loan into portions. Usually the split is a Fixed Portion and a Variable portion. The split can be set up at any percent eg: (50% - 50% split) or
(70% - 30% split).

By splitting your loan, you are spreading the risk. If the rates go up there may be a benefit to you however if the rates drop than you may be caught paying too much. It is for that reason some people like to hedge their bet. Others prefer the security of a Fixed Loan ensuring a non-fluctuating rate of payment and allowing for better budgeting.