Hohonu

Coastal cities don’t just need forecasts — they need street-level truth. Hohonu delivers hyperlocal, real-time water and flood intelligence that enables better emergency response and smarter long-term planning for coastal resilience. As sea levels rise and storms intensify, ports and municipalities lack the granular, real-time data they need to make informed decisions when it matters most. Hohonu bridges that gap with a flood monitoring, alerting, and forecasting platform that fuses ground-truthed sensors with predictive modeling — delivering actionable, street-by-street insights. We invested because Hohonu translates hydrology into operations, helping protect infrastructure, reduce downtime, and keep communities safe. Dive into the full story below — and save your seat for Katapult Ocean’s Digital Investor Day to meet the founders behind Hohonu and other pioneering blue-tech ventures: https://luma.com/8xrxfndm 🌊

How does a dense network of water level sensors help us understand changing flood impacts along the coast? Last week, much of the East Coast coast faced a double whammy: seasonal king tides and a nor'easter, causing widespread flooding. We saw an interesting opportunity along the NC coast to dig into the data and highlight some points we commonly encounter at Hohonu. NOAA operates a tide station at Wrightsville Beach (beachfront pier) and three of Hohonu’s sensors are in more sheltered bays at Topsail Beach, Surf City, and North Topsail Beach—spanning about 15-30 miles north. The first two figures cover October 11-13, 2025, showing the same data but referenced to different tidal datums: Mean Lower Low Water (MLLW) and Mean Higher High Water (MHHW). MLLW is a standard tidal datum that represents the average daily lowest tide. Leading into the storm, MLLW shows a tidal oscillation of over 5 feet on the open coast, compared with dampened ranges of ~1-4 ft for the backbay sites. This visualization also cleanly illustrates the time shifts between the southern open-ocean site and the backbay sites to the north.  We also see peaks in MLLW on 10/12 at all the stations, but how high were the peaks and what do they really mean? Water level reported as "5 feet above MLLW" at one station doesn't necessarily equate to the same absolute elevation (e.g., relative to mean sea level or land elevation) at another station nearby. Spatial variations in geomorphology, tide range, bathymetry, or other oceanographic factors can lead to significant variability. Persistent winds or storm surges further complicate matters for understanding if differences are due to tides or surge. MHHW is also a standard tidal datum, and represents the average daily highest tide. MHHW is often used as a reference point for coastal flooding because inundation typically begins when water levels exceed MHHW. This plot displays the same data, but now relative to MHHW. We can see how water levels elevate and linger in the back bay sites at Topsail, Surf City, and North Topsail. Topsail Beach experienced the highest surge stacked on its 10/12 high tide, while North Topsail remained at least +1 ft above MHHW all week. Takeaway For Topsail Beach, the peak water level on 10/12 (+6.0 ft MLLW / +2.9 ft MHHW) was the 4th highest that Hohonu has measured since our measurements began there in 2023, and were well above advisory thresholds (set by town managers) that are available as real-time text message alerts. For North Topsail Beach, waters never receded much even during low tides. These plots help reveal how datum choice frames the story: MLLW highlights common tidal oscillations, while MHHW helps interpret flooding potential above typical high tides. The differences between open-coast and inlet data, even over short distances, show why dense sensor networks are key for accurate local alerts & predictions. Thanks to NOAA IOOS SECOORA for providing funding for these three Hohonu stations!

We are thrilled to finally unveil the 8th Accelerator Cohort, bringing together 13 pioneering companies addressing some of the most urgent challenges in ocean innovation! 🌊 From carbon capture to pollution destruction, these 13 startups show how system-changing science is transforming ocean industries and the future of freshwater, food, and resilience. The cohort represents Katapult Ocean’s most technically advanced and commercially mature group of startups to date, with companies delivering IP-rich, science-driven solutions already piloted and validated with global customers and partners.  Read the full announcement and get to know all 13 companies below. 👇