RedactedNarrative: 14' homebuilt vessel was anchored approx. 200 yards from the reef (location: West side of Guam, closest to Mangilao)  while both individuals were spearfishing.  Upon returning to the vessel, they notice the vessel was partially submerged due to rough waters being 2' to 6' high.  Fishermen got to the vessel and called for assistance, to which both the Guam fire Rescue Unit and Navy HSC25 responded.