My views on the (non)value of a liferaft were confirmed recently by an ex SAR pilot.
He told me that of the 4 successful light aircraft ditchings he had attended where a liferaft had been carried, only two were able to get the raft out of the plane. Of the two that succeeded in extracting and inflating the raft, nobody was able to get aboard. Nobody. Apparently it is almost impossible in even the slightest sea.
His advice was:
1. Your best chance from a light a/c is in an immersion suit with a life jacket.
2. Dye or a streamer makes a big difference to visibility from above.
3. Never tow an aircraft behind a boat through the water backwards - it'll destroy it in minutes, even if travelling slowly.
To insist on the carriage of a liferaft is daft. The weight penalty reduces other options more likely to save your life.