The lifeguards launched the service's Sea Rider rescue vessel.
Mr Baker, Alex Tidyman and Jon Drucker had also responded and set up base at the MHVLS clubhouse, with Mr Baker controlling communications between the rescue vessel and Surf Com.
The Sea Rider attempted to navigate the Mangawhai Bar but conditions were too rough so they beached at the mouth of the harbour and sent Mr McInnes by land to the stranded vessel.
Two people were on board and, although they were cold and wet, they were unharmed.
The trimaran was grounded in a metre of water, and at first the crew wanted to stay on board and try to enter the Mangawhai Harbour later when the tide had come in.
"However, after some discussion the crew of the grounded vessel were taken back to the Mangawhai Surf Club to warm up," Mr Baker said.
When the tide had come in the Sea Rider crew helped bring the stranded and damaged vessel into the harbour, with the help of the two sailors.
They reached dry land at 10.30pm.
"This is the third sailing vessel that has run aground in Mangawhai Heads in the last 12 months. Just last week another yacht sank on the Mangawhai Bar, and the vessel broke up into sections due to large swells. Parts of this vessel are still submerged at the harbour entrance," Mr Baker said.
"This highlights the issue of poor preparedness and lack of knowledge of weather and local conditions by boaties leading to dangerous after-hours search and rescues on the Mangawhai Coast. From my perspective it's a silly mistake that can be very costly."