OPR-O190-FA-15West Prince of WalesWest Prince of WalesNOAA Ship FAIRWEATHERH127411Cape Bartolome to Port Santa CruzAlaskaUnited States200002015CDR David J. Zezula, NOAANavigable Area2015-03-022015-09-232015-10-06Multibeam Echo SounderMultibeam Echo Sounder BackscattermetersUniversal Transverse Mercator (UTM)UTCAtlantic Hydrographic BranchThe purpose of this survey is to provide contemporary surveys to update National Ocean Service (NOS) nautical charts. All separates are filed with the hydrographic data. Any revisions to the Descriptive Report (DR) generated during office processing are shown in bold red italic text. The processing branch maintains the DR as a field unit product, therefore, all information and recommendations within the body of the DR are considered preliminary unless otherwise noted. The final disposition of surveyed features is represented in the OCS nautical chart update products. All pertinent records for this survey, including the DR, are archived at the National Centers for Envitronmental Information (NCEI) and can be retrieved via http://www.ncei.noaa.gov/.NOAAThe survey area is located in Prince of Wales, AK, within the sub locality of Cape Bartolome to Port Santa Cruz.55.2964372222133.65468138955.1764455556133.403688333 H12741 Survey LimitsSupportFiles\H12741_Area_Surveyed.jpgSurvey limits were acquired in accordance with the requirements in the Project Instructions and the Hydrographic Survey Specifications and Deliverables (HSSD) dated May 2015.The purpose of this project is to provide contemporary surveys to update National Ocean Service (NOS) nautical charting products. This area is considered navigationally significant and of critical survey priority. The entire survey is adequate to supersede previous data.Inshore limit to 8 meters water depthEither complete multi-beam echo sounder (MBES) coverage with backscatter, or set line spacing (single beam echo sounder)SBES/MBES (100m spacing in restricted areas and around rocky points, 200m along open coasts).Greater than 8 meters water depthComplete MBES with backscatterAll coverage for survey H12741 was acquired using complete MBES with backscatter. In some areas, such as those around Cape Bartolome (Figure 2) and the west coast of Suemez Island (Figure 3), coverage to either the 4m curve or the sheet limit was not attained due to factors such as kelp, breakers, and sea state.H12741 Coverage Deviations Cape BartolomeSupportFiles\H12741 Cape Bartolome Coverage Deviations.jpgH12741 Coverage Deviations Suemez IslandSupportFiles\H12741 Suemez Island Coverage Deviations.jpgH12741 Survey OutlineSupportFiles\H12741_Survey_Outline.jpgS2200206.650000025.5802808077.75000004.130280702.2800000002806079.0200000002805046.69000006.4900408.410000036.2108.8715114037.222015-09-232015-09-242015-09-252015-09-262015-09-272015-09-292015-10-082015-10-092015-10-152015-10-242015-10-252015-11-042015-11-05Refer to the Data Acquisition and Processing Report (DAPR) for a complete description of data acquisition and processing systems, survey vessels, quality control procedures and data processing methods. Additional information to supplement sounding and survey data, and any deviations from the DAPR are discussed in the following sections.S22070.44.728088.641.1228078.641.1228068.641.1228058.641.12Reson7125 SV1MBESKongsbergEM710MBESSeabird19plusConductivity, Temperature, and Depth SensorResonSVP70Sound Speed SystemResonSVP71Sound Speed SystemApplanixPOS/MV V4Positioning and Attitude SystemRolls RoyceMVP200Conductivity, Temperature, and Depth SensorCrosslines were collected, processed and compared in accordance with section 5.2.4.3 of the HSSD. All crosslines were filtered 45 degrees from nadir on the port and starboard sides with the exception of two crosslines: 2015X_2662327 and 2015X_2702339 whose outer beams are accepted to augment coverage requirements of both sheet limits and mainscheme holiday coverage. See Figures 12 and 13. Surface Differencing in CARIS HIPS and SIPS was used to assess crossline agreement with main scheme lines. A difference surface was created from a 16 meter crossline surface. Differences in crossline to main scheme lines are caused by steep slope and the rocky nature of the seafloor. Detailed graphical views can be seen in Figures 5 through 9 . See Figure 10 for a statistical analysis of the difference surface that indicates 95% of all nodes have a maximum deviation of +/- 2.15 meters with a mean deviation of 0.11 meters . This deviation falls within the total allowable uncertainties for these depths as seen in Figure 11 where green represents data within allowable uncertainties and red represents data exceeding allowable uncertainty. The difference surface is submitted digitally in the Separates/II Digital Data folder. H12741 Crossline Difference Graphical OverviewSupportFiles\XL_Difference_Overview.jpgH12741 Graphical Zoom of Area 1 Crossline DifferencesSupportFiles\XL_Difference_Area_1_Zoom.jpgH12741 Graphical Zoom of Area 2 Crossline DifferencesSupportFiles\XL_Difference_Area_2_Zoom.jpgH12741 Graphical Zoom of Area 3 Crossline DifferencesSupportFiles\XL_Difference_Area_3_Zoom.jpgH12741 Graphical Zoom of Area 4 Crossline DifferencesSupportFiles\XL_Difference_Area_4_Zoom.jpgH12741 Main-scheme and Crossline Difference StatisticsSupportFiles\H12741_Crossline_Difference_April_11.jpgH12741 Crossline Surface Showing Allowable UncertaintySupportFiles\NOAAness_XL_With_Colour_Key.jpgH12741 Crossline Port Side Beams Re-accepted For Holiday Coverage NW Santa Cruz BaySupportFiles\Reaccept port beams N Santa Cruz zoom.jpgH12741 Crossline Port Side Beams Re-accepted For Holiday Coverage NW Point BartolomeSupportFiles\Reaccept port beams W Point Bartolome zoom.jpg00TCARI00.25Discrete ZoningS22010.5280820.5280720.5280620.5280520.5During acquisition, discrete tidal zoning uncertainty values were processed in CARIS HIPS and SIPS, at the receipt of final Tidal Constituents and Residual Interpolation (TCARI) the values were changed. The values shown in Table 6 above were entered into CARIS HIPS and real-time values incorporated in the TCARI grid were used. In addition to the usual a priori estimates of uncertainty, some real-time and post-processed uncertainty sources were also incorporated into the depth estimates of survey H12741. Real-time uncertainties from both the EM710 and Reson 7125 data were recorded and applied in post-processing. Applanix TrueHeave files are recorded on all survey vessels, which includes an estimate of the heave uncertainty, and are applied during post-processing. Finally, the post-processed uncertainties associated with vessel roll, pitch, gyro and navigation are applied in CARIS HIPS via an SBET RMS file generated in POSPac.The areas of overlap between surveys were reviewed with CARIS HIPS and SIPS by surface differencing the 8 meter combined surface for H12742, and 16 meter combined surfaces for surveys H12292 and H12293 to assess surface agreement. The junction agreement is generally within the total allowable vertical uncertainty in their common areas and depths for all surfaces. Data overlap between all surveys was achieved. See Figure 14 for all areas of overlap. Junctions Between H12741,H12742,H12292,H12293SupportFiles\H12741_Junction_Survey_Overview.jpgH12742200002015NOAA Ship FAIRWEATHERESurface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the 8 meter combined surfaces from H12741 and the 8 meter combined surface from H12742. A graphical overview can be seen in Figure 15, the red circles indicating where the largest differences are. A Statistical Analysis can be seen in Figure 16 where the difference surface indicates 95% of all nodes have a maximum deviation of +/- 2.42m with a mean deviation of -0.64m. The largest differences are located in the north area west of Cape Felix where the seafloor steeply shallows along the shore. Figure 17 highlights this area. Other areas with large differences are due to undeveloped data collected in the outer beams at the sheet limits over steep rock faces shared with survey H12742. Junction Between H12741 and H12742SupportFiles\H12741_H12742_Difference_Overview_meters.jpgDifference Statistics H12741 and H12742SupportFiles\H12741_H12742_Difference_Stats.jpgGraphical Overview of Area With Large DifferenceSupportFiles\H12741_H12742_Difference_North_Overview.jpgH12292200002011NOAA Ship RAINIERNSurface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the 16 meter combined surfaces from H12741 and the 16 meter combined surface from H12292. The statistical analysis of the difference surface indicates 95% of all nodes have a maximum deviation of +/- 2.44 meters, with a mean deviation of 0.44m as shown in Figure 19. A detailed graphical overview can be seen in Figure 16. The largest differences are located in the middle of Bucareli Bay: A zoom-in of a the surface difference in circle A can be seen in the top right corner of Figure 18. Though relatively flat in this area, it is possible that the large tidal movements seen throughout SE Alaska have caused the relocation of the ocean floor sediment. Another area of large difference is shown in circle B in Figure 18 which can be explained by the dynamic nature of the seafloor and its very steep inclines. Junction Between H12741 and H12292SupportFiles\H12741_H12292_Difference_Overview.jpgDifference Statistics of H12741 and H12292SupportFiles\H12741_H12292_Difference.jpgH12293200002011NOAA Ship RAINIERWSurface differencing in CARIS HIPS and SIPS was used to assess junction agreement between the 16 meter combined surfaces from H12741 and the 8 meter combined surface from H12293. Both sets of data at this junction reflect a relatively flat seafloor with less difference than that of Junctions H12742 and H12292 where rocky areas significantly increase differences between surfaces. The statistical analysis of the difference surface indicates 95% of all nodes have a maximum deviation of +/- 1.56m with a mean deviation of 0.41m and can be seen in Figure 21. Differences exist in the more dynamic regions of Junction H12741 and H12293, see the outlined areas A,B and C seen in Figure 20.Junction Between H12741 and H12293 SupportFiles\H12741_H12293_Difference_Zoom.jpgDifference Statistics of H12741 and H12293SupportFiles\H12741_H12293_Difference_Stats.jpgSonar system quality control checks were conducted as detailed in the quality control section of the DAPR.Opperational Effectiveness Exceeded for RESON 7125 200kHzDuring survey acquisition on DN 298, Fairweather launch 2808 ran an east to west line at approximately 2kts across Survey H12741 to pickup a holiday at the edge of the sheet limits. The depth at which line 2015M_2982153 was acquired exceeded the limitations of the RESON 7125 200kHz. Excessive noise was present while viewing through CARIS HIPS and SIPS Subset Editor causing the CUBE surface to misrepresent the sea floor. The outer most beams and any other noise affecting the surface was rejected at the discretion of the hydrographer and the surfaces were recomputed resulting in no impact to data quality. The remaining beams on line 2015M_2982153 most accurately represent the surface. See Figures 22 and 23. H12741 Sheet Limits Holiday Coverage Rejected Outer Beams OverviewSupportFiles\Sheet Limits Holiday Pick Up 200kHz blowouts Overview.jpgH12741 Sheet Limits Holiday Coverage Rejected Outer Beams Subset Side ViewSupportFiles\Sheet Limits Holiday Pick Up 200kHz Blowouts Side View.jpgSea Grass and KelpIn shoal areas of survey H12741 there is a noticeable effect of kelp and sea grass on the Cube surfaces. The most notable are southwest of Point Isleta seen in Figure 24 and west of Pt. Santa Cruz Bay seen in Figure 25. For areas where charted sea grass or kelp obscured the bottom, very little cleaning was done near the surface so as not to inadvertently clean out any rocks. Where charted kelp was present and was distinguishable from features, it was cleaned out at the hydrographer's discretion. See Figure 26 for a Subset view of the effect of kelp on the CUBE surface and Figure 27 where the hydrographer rejected data due to kelp.H12741 Example of The Effect of Sea Grass on The Cube Surface SupportFiles\Seagrass effecting soundings Port Santa Cruz Overview.jpgH12741 Graphical Overview of Example of The Effect of Kelp on The Cube Surface SupportFiles\H12741 West Pt. Cruz Kelp in Cube Surface Overview.jpgH12741 Graphical Subset of Example of The Effect of Kelp on The Cube Surface SupportFiles\H12741 West Pt. Cruz Kelp in Cube Surface Subset.jpgH12741 Example of Kelp Rejected at Hydrographers Discretion in Santa Cruz BaySupportFiles\Kelp Cleaned by Hydrographer.jpgSea StateDuring acquisition on survey H12741, the survey launches experienced periods of high sea-state and breakers due to weather causing excessive pitching. The results of the pitching were periods of blow-outs in the surface sound speed due to launch attitude. These blow-outs caused erroneous soundings which effected the CUBE surface. The MBES data was reviewed in CARIS HIPS and SIPS subset editor with appropriate reference surfaces, data effecting the CUBE surface was cleaned out. The bathymetry accurately depicts the sea floor. An example of these blow-outs can be found below in Figures 28 and 29. Also during acquisition on Survey H12741, survey launch 2808 experienced excessive rolling while acquiring crossline: 2015X_2702339 NW of Cape Bartolome. The image below in Figure 30 shows the Cube surface with a 10x exaggeration. Figure 31 shows a 3D subset representation of the roll artifact.H12741 Surface Sound Speed Blow-outs Overview West of Cape FelixSupportFiles\West Cape Felix Surface Sound Speed blowouts Overview.jpgH12741 Surface Sound Speed Blow-out Subset View SupportFiles\West Cape Felix Surface Sound Speed blowouts Subset.jpgH12741 Overview of Excessive Rolling During Acquisition of CrosslineSupportFiles\Roll Artifiact in XL Surface NW Cape Bartolome.jpgH12741 Subset View of Excessive Rolling During Acquisition of CrosslineSupportFiles\Roll Artifiact in XL Surface NW Cape Bartolome Subset.jpgHeave and yaw artifacts are more apparent in Figure 30 than roll artifacts.Vertical Offset During the survey of sheet H12741, data was acquired on different days in adjacent areas NW of Cape Bartolome. After reviewing the data that overlapped in these areas in CARIS HIPS and SIPS Subset Editor, a minor vertical offset of .35m was observed between data collected with S220 EM710 and 2808 400kHz. The offset observed does not fall outside the Total Vertical Allowable Uncertainty set by IHO order 1. This vertical offset was found to be more pronounced when GPS tides were applied. The data meets all NOAA specifications and the hydrographer recommends survey data supersede charted depths and contours. See a graphical overview in Figure 32 with its accompanied Subset view in Figure 33. Figure 34 shows a graphical view of a crossline acquired NW of Cape Bartolome that also exhibits a vertical offset of 0.25m when observed in CARIS HIPS and SIPS Subset Editor. See Figure 35 for a subset view of this crossline. H12741 Graphical Overview Vertical Offset NW Cape BartolomeSupportFiles\Tide Artifact in Surface NW Cape Bartolomesnag.jpgH12741 Subset View Vertical Offset NW Cape BartolomeSupportFiles\Tide Artifact in Surface NW Cape Bartolome Subset.jpgH12741 Graphical Overview of Vertical Offset NW Cape Bartolome CrosslineSupportFiles\Roll Artifiact in XL Surface NW Cape Bartolome.jpgH12741 Subset of Vertical Offset NW Cape Bartolome CrosslineSupportFiles\Additional Vertical Offset XL Surface NW Cape Bartolome Subset.jpgDuring launch acquisition, casts were conducted at least every four hours. Casts were conducted every 15-40 minutes while towing the Moving Vessel Profiler during ship acquisition.All equipment and survey methods were used as detailed in the DAPR.IHO Uncertainty To assess vertical accuracy standards, a child layer titled "IHO1" was created for each of the 1-meter, 2-meter, 4-meter and 8-meter finalized surfaces. "IHO2" child layers were created for each of the 8-meter and 16-meter finalized surfaces, using the equation as stated in section C.2.1 of the DAPR. See Figures 43 to 47 and the Standards Compliance Review in Appendix II for detailed statistics. The data meets the accuracy specifications as stated in the NOS Hydrographic Surveys Specifications and Deliverables (HSSD) dated May 2015. It was found that at least 95.4% of the nodes in all finalized surfaces meet or exceed IHO order 1 specifications. Areas with high IHO uncertainty are highlighted in red by CARIS HIPS and SIPS and can be seen below in Figure 36. Figures 37 and 38 show an example of high IHO uncertainty where minimal to no overlap was attained, resulting in low density where the sea floor slope changes. Figures 39 and 40 show an example of high IHO uncertainty where CARIS Beam Disabling occurs causing low density. Figures 41 and 42 show an example of High IHO Uncertainty Due to minimal to no overlap over dynamic seafloor. The southern and southwestern border of H12741 exhibit high uncertainty where there is no data to overlap the outer beams. H12741 Graphical Representation of IHO UncertaintySupportFiles\H12741_IHO_Overview.jpgH12741 Graphical view of Southeast Cape Bartolome Area of High IHO Uncertainty, Minimal Overlap Over Dynamic SeafloorSupportFiles\Little to no overlap dynamic seafloor IHO Uncertainty D.jpgH12741 Subset View of Southeast Cape Bartolome Area of High IHO Uncertainty, Minimal Overlap Over Dynamic SeafloorSupportFiles\Little to no overlap dynamic seafloor IHO Uncertainty D Zoom.jpgH12741 Graphical View of High IHO Uncertainty Where CARIS Disabled BeamsSupportFiles\CARIS Disabled beams IHO Uncertainty A .jpgH12741 Subset View of High IHO Uncertainty Where CARIS Disabled BeamsSupportFiles\CARIS Disabled beams IHO Uncertainty A1 Zoom.jpgH12741 Graphical View of High IHO Uncertainty Due to Minimal to No Overlap Over Dynamic SeafloorSupportFiles\Little to no overlap IHO Uncertainty C.jpgH12741 Subset View of High IHO Uncertainty Due to Minimal to No Overlap Over Dynamic SeafloorSupportFiles\Little to no overlap IHO Uncertainty C1.jpgH12741 1m Finalized Surface Uncertainty StatisticsSupportFiles\H12741_MB_1m_MLLW_Final_TVU_QC.pngH12741 2m Finalized Surface Uncertainty StatisticsSupportFiles\H12741_MB_2m_MLLW_Final_TVU_QC.pngH12741 4m Finalized Surface Uncertainty StatisticsSupportFiles\H12741_MB_4m_MLLW_Final_TVU_QC.pngH12741 8m Finalized Surface Uncertainty StatisticsSupportFiles\H12741_MB_8m_MLLW_Final_TVU_QC.pngH12741 16m Finalized Surface Uncertainty StatisticsSupportFiles\H12741_MB_16m_MLLW_Final_TVU_QC.pngDensity ComplianceDensity requirements for the 1m, 2m, 4m, 8m and 16m finalized surfaces for H12741 were achieved with at least 99.5% of finalized surface nodes containing five or more soundings. See Figures 53 to 57 and the Standards Compliance Review in Appendix II for full statistics. An overview of H12741 Density is provided in Figure 48. Areas of low density can be seen in the figures below: Figures 49 and 50 show an example of low density east of Pt. Rosary due to southern swell causing excessive yaw and push of survey vessel while operating within the vessel speed constraints of the RESON 200kHz multibeam sonar. Figures 51 and 52 show an example of low density, less than 5 pings per node, southwest of Cape Felix due to minimal overlap and east winds 10 to 15kts with 3-6ft seas causing excessive yaw of the survey vessel.H12741 Density Overview SupportFiles\Density Overview.jpgH12741 Graphical Overview of Low Density Due to Southern SwellSupportFiles\Low Density Due to Southern Swell 2805 A.jpgH12741 Subset of Low Density Due to Southern Swell SupportFiles\Low Density Due to Southern Swell 2805 A1.jpgH12741 Graphical Overview of Low Density Due to East Winds 10 to 15ktsSupportFiles\Low Density Due to Yaw 2808 A.jpgH12741 Subset of Low Density Due to East Winds 10 to 15kts SupportFiles\Low Density Due to Yaw 2808 A1 Zoom.jpgH12741 1m Finalized Surface Density StatisticsSupportFiles\H12741_MB_1m_MLLW_Final_Density.pngH12741 2m Finalized Surface Density StatisticsSupportFiles\H12741_MB_2m_MLLW_Final_Density.pngH12741 4m Finalized Surface Density StatisticsSupportFiles\H12741_MB_4m_MLLW_Final_Density.pngH12741 8m Finalized Surface Density StatisticsSupportFiles\H12741_MB_8m_MLLW_Final_Density.pngH12741 16m Finalized Surface Density StatisticsSupportFiles\H12741_MB_16m_MLLW_Final_Density.pngHoliday AssessmentH12741 data was reviewed in CARIS HIPS and SIPS. The May 2015 HSSD was used when assessing H12741 for holidays. Holidays are present in H12741 due to the following four factors: 1. Sea State (Holiday-pickup called off on DN 309 due to worsening seas) Refer to scanned boat sheets in Separates I Acquisition and Processing Logs Detached Positions for additional reference. 2. Foul areas of Kelp 3. Steep slope in rocky areas 4. Falling Tide Near Features The least depths of all navigationally significant features are represented by H12741, with the exception of the examples below in Figures 59 and 60. Figure 58 represents an example of a holiday northwest of Cape Bartolome where launch operations ceased due to large breakers and rising swells. Other holidays outlined on Boat sheets for vessel 2807 Day Number 309 are included in this category. Figures 59 and 60 show an overview on the west coast of H12741 where the least depth of a feature was unable to be attained due to limits of hydrography i.e. the safe maneuverability of the survey vessel and large breakers. Figures 61 and 62 show an example of areas which occur on both the east and west coasts of Survey H12741 that have incomplete multi-beam data due to acoustic shadows caused by steep downslope and the rocky nature of the coastline. Figures 63 and 64 display an example in Santa Cruz Bay of incomplete coverage due to foul areas with kelp. Holidays are present in the south bowl of Santa Cruz Bay near shore of Pt. Cruz due to dense kelp beds, refer to Section B.2.6 Factors Affecting Soundings and their images.H12741 Graphical Overview of Holiday Due to Breakers Around IsletSupportFiles\Breakesrs West Cape Bartolome Islet.jpgH12741 Graphical Overview of Holiday Due to Sea StateSupportFiles\Overview Holiday on Top of Rock 1a.jpgH12741 Graphical 2D Subset of Holiday Due to Sea stateSupportFiles\Subset Holiday On Top of Rock 1b.jpgH12741 Graphical Overview of Holidays Due to Downslope of Rocky Coastal LineSupportFiles\Downslope Holidays South Point Rosary 1.jpgH12741 Graphical Subset of Holidays Due to Downslope of Rocky Coastal LineSupportFiles\Downslope Holidays South Point Rosary 2.jpgH12741 Graphical Overview of Holiday Due to Steep Downslope of Rocky Coastal LineSupportFiles\1m_Holiday_Santa_Cruz_Bay steep slope_Overview.jpgH12741 Subset View of Holiday Due to Steep Downslope of Rocky Coastal LineSupportFiles\1m_Holiday_Santa_Cruz_Bay steep slope_Subset.jpgAll data reduction procedures conform to those detailed in the DAPR.All sounding systems were calibrated as detailed in the DAPR.Raw Backscatter was logged as a 7k file and has been sent to the Processing Branch. One line per day, per vessel of Backscatter was processed in the field by the field unit for quality control.CarisHIPS/SIPS9.0NOAA Profile V_5_3_3H12741_MB_1m_MLLWCUBE1-1.063433.781NOAA_1mComplete MBESH12741_MB_2m_MLLWCUBE2-0.788363.994NOAA_2mComplete MBESH12741_MB_4m_MLLWCUBE4-0.915347.238NOAA_4mComplete MBESH12741_MB_8m_MLLWCUBE8-0.367308.758NOAA_8mComplete MBESH12741_MB_16m_MLLWCUBE16-0.311308.651NOAA_16mComplete MBESH12741_MB_1m_MLLW_FinalCUBE1-320NOAA_1mComplete MBESH12741_MB_2m_MLLW_FinalCUBE21840NOAA_2mComplete MBESH12741_MB_4m_MLLW_FinalCUBE43680NOAA_4mComplete MBESH12741_MB_8m_MLLW_FinalCUBE872160NOAA_8mComplete MBESH12741_MB_16m_MLLW_FinalCUBE16144320NOAA_16mComplete MBESH12741_MB_16m_MLLW_CombinedCUBE1600NOAA_16mComplete MBESThe NOAA parameters mandated in the HSSD were used for the creation of all CUBE BASE surfaces in Survey H12741. The surfaces have been reviewed where noisy data, or 'fliers' are incorporated into the gridded solution causing the surface to be more shoal or deeper than the true sea floor. Where these spurious soundings cause the gridded surface to be shoaler or deeper than the reliably measured seabed by greater than the maximum allowable Total Vertical Uncertainty at that depth, the noisy data have been rejected and the surface recomputed. Data LogsData acquisition and processing notes are included in the acquisition and processing logs, and additional processing such as final tide and sound velocity application are noted in the H12741 Data Log spreadsheet. All data logs are submitted digitally in the Seperates I folder.Critical SoundingsDesignation of soundings followed procedures as outlined in section 5.2.1.2 of the HSSD. Survey H12741 contains 29 soundings which are designated in CARIS HIPS and SIPS. These designated soundings were used to draw the CUBE surface to the sounding which most accurately represented the sea floor in cases where the surface deviated from the sounding more than the total allowable vertical uncertainty in accordance with HSSD 2015. Designated soundings were necessary primarily in rocky areas.CARIS Automatic Beam DisablingDuring conversion of the EM710 data in CARIS HIPS and SIPS, some soundings were rejected due to disabled beams causing areas of low density soundings. See Figures 65 and 66 below for an example of where beam disabling was present due to the steep slope of the seafloor. Per instructions from CST Bravo, data from disabled beams were not re-accepted. H12741 Graphical Overview EM710 CARIS Automatic Beam DisablingSupportFiles\H12741_CARIS_Disabled_Beam_Overview.jpgH12741 Subset EM710 CARIS Automatic Beam DisablingSupportFiles\H12741_CARIS_Disabled_Beam_Subset.jpgInconsistent Number of HSX, 7K, RAW FilesDue to numerous Hypack software crashes during acquisition on survey H12741 there are a number of days that have a contrasting number of data files. Refer to H12741_Data_Log where the record of PreProcess, HDCS_DATA, and Backscatter data differ in quantity. This anomaly did not affect data for charting purposes. The only data affected was the loss of 7K files resulting in no backscatter data being available.Additional information discussing the vertical or horizontal control for this survey can be found in the accompanying HVCR.Mean Lower Low WaterSitka, AK9451600Port Alexander, AK9451054Block Island, AK9450406Discrete ZoningTCARI9451600.tidVerified ObservedO190FA2015_Final.tcFinalO190FA2015CORP.zdfPreliminary2015-11-182016-03-11A final Tidal Constituents and Residual Interpolation (TCARI) grid was issued in order to provide a better uncertainty value for OPR-O190-FA-15. Due to a sensor stability issue at Block Island, AK 9450406, the harmonic constituents and tidal datums from this station are not included in the TCARI solution. It should be noted that the TCARI error model underestimates the error in the area around Block Island.The .tid file used for TCARI tide application was 9451054.tid.North American Datum of 1983 (NAD83)UTM Zone 8 NorthSingle Base9677WaterfallVessel kinematic data were post-processed using Applanix POSPac processing software and Single Base Positioning methods described in the DAPR. Smoothed Best Estimate of Trajectory (SBET) and associated error (RMS) data were applied to all MBES data in CARIS HIPS. For further details regarding the processing and quality control checks performed see the H12741 POSPAC Processing Logs spreadsheet located in the Separates folder. See also the OPR-0190-FA-15 Horizontal and Vertical Control report, submitted under separate cover. Gustavus, AK (288kHz)Annette Island, AK (323kHz)Differential correctors from the US Coast Guard beacons at Gustavus (288kHz) and Annette Island (323kHz) were used during real time acquisition when not otherwise noted in the acquisition logs, and were the sole method of positioning of detached positions (DP) and bottom samples.A comparison was performed between survey H12741 and Charts 17406 and 17400 as well as Electronic Navigation Charts (ENC): US3AK40M and US5AK4TM using CARIS sounding and contour layers derived from the 16 meter combined surface. The contours and soundings have been overlaid on the chart to assess differences. All data from H12741 should supersede charted data. 1740612344000082013-102015-01-102014-12-30Soundings from survey H12741 generally agreed within 1 to 2 fathoms with charted depths on Chart 17406, however, there are numerous areas within the survey limits that have more significant disagreements. Included below with graphics and brief descriptions are examples of notable exceptions to this general agreement, specifically surveyed soundings shoaler than charted depths by 3 fathoms or more. 1. Surveyed soundings that are shoaler by 10 or more fathoms than charted are present throughout Survey H12741. See Figure 67 for an example. 2. Surveyed soundings of shoal rock formations in deep water are not adequately charted. An example is given below in Figure 68. 3. Surveyed soundings located near shore in disagreement to charted depths are shown below in Figure 69. Figure 70 displays a 13 fathom surveyed sounding on the point of Cape Bartolome where a currently charted depth of 29 fathoms exists. This surveyed sounding of 13fm was reviewed in CARIS HIPS and SIPS Subset Editor and submitted to the Chief of Party for review as a potential DTON. Because of the surveyed sounding's proximity to the rocky and breaker-ridden point of Cape Bartolome it was determined to not be a danger to navigation. The hydrographer recommends updating the chart to reflect the shoalest sounding. Contours generated in CARIS HIPS and SIPS closely approximate the charted 10, 50, and 100 fathom contours. The two greatest contour discrepancies can be seen in Figure 71 where in the southwest corner of survey H12741. The 50 fathom surveyed contour is located approximately 552 meters east of the charted 50 fathom contour. Similarly, in the southern middle part of survey H12741 the 100 fathom surveyed contour is located approximately 550 meters east of the charted 100 fathom contour. An additional area of interest seen in Figure 73 is located in the south western corner of the survey where the 50 fathom surveyed contour is approximately 354 meters west of the charted 50 fathom contour. The hydrographer recommends adding an additional 50 fathom contour as pictured in Figure 72 below. H12741 Example of Difference in Surveyed Soundings to Charted Depths by 10 or More FathomsSupportFiles\12_Shoaler Soundings top mid sheet.jpgH12741 Example of Surveyed Shoaler Sounding in Proximity to Deeper Charted DepthSupportFiles\08_Shoaler Soundings Southeast sheet.jpgH12741 Example of Surveyed Soundings in Disagreement to Nearshore Charted DepthSupportFiles\A_Shoaler Sounding close to shore.jpgH12741 Surveyed Sounding in Disagreement to Charted Depth Near Point BartolomeSupportFiles\03_Shoaler Soundings West 13fm near 29fm Point Bartolome.jpgH12741 Graphical Overview of Contour ComparisonSupportFiles\Contours 10_50_100 Overview.jpgH12741 Graphical Overview Recommendation to Add 50 Fathom Surveyed Contour to ChartSupportFiles\Contours 50fm recommend adding.jpgH12741 Graphical Overview of Contour ComparisonSupportFiles\Contours 50fm discrepancy.jpg174002715229376182013-092015-01-102014-12-30The sounding comparison between H12741 and Chart 17400 closely resembles that performed to Chart 17406. See discussion above. Figure 74 shows two soundings on the Southern end of the survey area where surveyed soundings disagree with charted depths by as much as 30 fathoms.H12741 Sounding Discrepancies With Chart 17400SupportFiles\17400 sounding discrepanicies.jpgUS3AK40M22937672014-04-072014-12-15falseSoundings from H12741 generally agreed within 1 to 2 fathoms on ENC US3AK40M. Notable exceptions to charted depths are listed and shown in the figures below. Figure 75 displays where ENC US3AK40M was overlaid on Chart 17406 and was found to have one of many charted soundings on the ENC that are located over 100 meters away from the charted depths on Chart 17406. Its location misrepresents the more accurate location of charted depths on Chart 17406 and gives a false sense of disagreement in surrounding surveyed depths. The hydrographer recommends using surveyed soundings to update charted depths to update the accuracy between RNCs and ENCs. Figure 76 shows one of few charted ENC depths that has a 30 fathom disagreement with H12741 surveyed soundings Contours in CARIS HIPS closely approximate the charted contours, deviations from this general agreement are seen in the southern area of Survey H12741 where both the 100 and 50 fathom surveyed contours are located over 300 meters or more away from the charted contours. An overview of these differences is shown below in Figure 77. H12741 Sounding Proximity Between Chart 17406 and ENC US3AK40MSupportFiles\17406 US3AK40M Discrepancies.jpgH12741 Difference Between Charted Depths US3AK40M and Surveyed Soundings: 30 Fathom Shoaler Disagreement With Charted DepthSupportFiles\Sounding difference ENC US3AK40M of 30fm on south of sheet .jpgH12741 and US3AK40M 50 Fathom Contour ComparisonSupportFiles\Contours 50fm discrepancy US3AK40M.jpgUS5AK4TM4000022014-02-242016-04-07falseSee above discussions from Raster Chart 17406 for discussions on sounding comparisons and contours.All assigned Maritime Boundary Points for survey H12741 were investigated, and are included in the H12741_Final_Feature_File. All assigned features were addressed and are included in the H12741_Final_Feature_File.No uncharted features exist for this survey.No Danger to Navigation Reports were submitted for this survey.No shoals or potentially hazardous features exist for this survey.No channels exist for this survey. There are no designated anchorages, precautionary areas, safety fairways, traffic separation schemes, pilot boarding areas, or channel and range lines within the survey limits.Fifteen out of fifteen bottom samples for H12741 were collected and attributed and are located in the H12741 Final Feature File. Locations can be seen in the figure below.H12741 Bottom Sample LocationsSupportFiles\bottom sample locations.jpgFairweather personnel conducted limited shoreline verification and reconnaissance at times near predicted low tides, however, no negative tides were present during the days of acquisition. Annotations, information, and diagrams collected on DP forms and boat sheets during field operations are scanned and included in the digital Separates I folder. Shoreline verification procedures for survey H12741 conform to those detailed in the DAPR. Prior survey comparisons exist for this survey, but were not investigated.All ATONs within the survey limits of H12741 were found to be serving their intended purpose.No overhead features exist for this survey.No submarine features exist for this survey.One cable area was noted in the survey area.No ferry routes or terminals exist for this survey.No platforms exist for this survey.No Significant Features exist for this survey.No present or planned construction or dredging exist within the survey limits.No new surveys or further investigations are recommended for this area.No new insets are recommended for this area.As Chief of Party, field operations for this hydrographic survey were conducted under my direct supervision, with frequent personal checks of progress and adequacy. I have reviewed the attached survey data and reports.All field sheets, this Descriptive Report, and all accompanying records and data are approved. All records are forwarded for final review and processing to the Processing Branch.The survey data meets or exceeds requirements as set forth in the NOS Hydrographic Surveys and Specifications Deliverables Manual, Field Procedures Manual, Letter Instructions, and all HSD Technical Directives. These data are adequate to supersede charted data in their common areas. This survey is complete and no additional work is required with the exception of deficiencies noted in the Descriptive Report.CDR David J. Zezula, NOAAChief of Party2016-04-13LT Matthew M. Forney, NOAAField Operations Officer2016-04-13HCST Douglas A. BravoChief Survey Technician2016-04-13HSST Clinton R. MarcusSheet Manager2016-04-13Data Acquisition and Processing Report2016-04-21Coast Pilot Report2016-05-03Horizontal and Vertical Control Report2016-05-05