Houghs Neck, Quincy, MA to Hull Gut and Peddocks Island Circumnavigation. 12:00Am-4:00Pm. Two Pods, Bob L
Total Page:16
File Type:pdf, Size:1020Kb
4/14/2018: Houghs Neck, Quincy, MA to Hull Gut and Peddocks Island circumnavigation. 12:00am-4:00pm. Two pods, Bob L (Green Explorer), Marc P, Shari G, Jim S, Christopher C; and Jeff C, Peter B, Sue H, Karen G, and Patrick D. Boston Harbor Navigation paddle. HT 10:55am 10.1 feet, LT 5:04pm 0.2 feet. Tidal range 9.9 feet, near last quarter moon. Low 40F air, mid 40F water, 1-2 foot chop, NE winds increasing to 15-20 kts as late afternoon storm approaches. We met 11am at Houghs Neck in Quincy. There was a brief consult with the harbormaster, who had kindly left the office doors open for us to dress and use the restrooms. In the pre-paddle briefing we discussed the overall goal for the day being an on-water review of navigation as we paddled around Peddocks Island. We further considered the big picture for paddling around Hull, Hingham, and Quincy Bays. To summarize: The area has unique tidal dynamics of a scale less than, but approaching, the river systems around Boothbay in Maine. Due to the importance of Boston as a commercial port, the harbor currents are extensively mapped by NOAA. Figure 1 contains the marine chart of Boston Harbor showing the area we paddled. Appendix A is a data sheet showing currents for April 14-15 taken from the NOAA website. The appendix also has a chart, Figure A1, showing the locations of reported NOAA currents and rotary currents. There are two constrictions, West Gut and Hull Gut. The situation on the day of the paddle, 4/14/2018, captures the properties of flow around Peddocks involving these two guts. West Gut (data sheet graph #1) had a slack-before-ebb around 11:36am whereas Hull Gut had slack-before-ebb (data sheet graph #3) at 10:18am. That means that Hull had started ebbing a full 1.25 hours before West Gut. During this time, water was pouring out of Hull and entering through West. Water levels continued to rise until 10:55am when the drain from Hull finally turned the tide against the slowing West Gut flood. Once started, the Hull ebb reached a peak value at 2.32kts at 3:00pm, before ending at 4:54pm. During this long Hull ebb, the delayed West Gut ebb had started to drop from a peak value of 1.43kts at 2:03pm until hitting slack-before-flood at 4:59pm. The two guts are coincident at the slack- before-flood. The lag in ebb between West and Hull is due to the fact that West Gut is more exposed to the larger Boston Harbor tidal cycle through Quincy Bay, whereas Hull Gut is controlled by Hull and Hingham Bays. The two distinct phases were 10:18am-11:36am, water flowing in from West and out through Hull (cycling around Peddocks), and then 11:36am- 4:59pm, water flowing out through both Hull and West. These are shown in Figure 2. The current station #7R on the data sheet chart indicates a rotary current along the eastern shore of Peddocks. It is mostly flowing up to 0.4kts in a northerly direction towards Hull Gut, but had a few hours of stalled westerly flow. AREA OF PADDLE Figure 1: Chart of Massachusetts Bay and Boston Harbor. Area of Paddle Indicated. Note constrictions of Hull and West Guts and locations of Hull, Hingham, and Quincy Bays. PHASE I: 10:18am-11:36am PHASE II: 11:36am-5:00pm Figure 2: Phases of Tidal Flow around Peddocks Island on April 14, 2018. After the briefing, we first moved out onto the Hough’s Neck dock and oriented charts to recognize Pig Rock, and Sheep, Bumkin and Grape Islands. I tried my arms-length thumb estimate of the Grape Island range. As seen on the Figure 3 chart, the island contours, separated by 20 feet, have a maximum at 80 feet. Assuming a peak halfway between contours (90 feet) we would have an 80 foot height-above-sea-level at high tide. My sighted thumbnail was just covering the island so, with a length of 1cm on an 80cm extended arm, we have a range 80/(1/80)=6400 feet. Taking 6000 feet/nm (actual value is 6076 feet), I found one and 1/15th nautical miles to the island. A quick check from the chart was 1.2 nautical miles. That was a reasonable result given the uncertainties in arm length and height. A more careful analysis at home; eye-to-thumb of 85cm, and using the 6076 feet/nm; I get 1.12nm estimate of a 1.18nm range – which is amazingly accurate! Of course, you would never use numbers like 85 and 6076 on the water unless you had a Gauss-like brain condition. We also tried horizontal estimates of distance using the British Army (reference Gatty and Eyges below) technique of looking at the shift of a finger at arm’s length sighted with left then right eye. I also counted knuckles of an extended fist. We ran out of time, and would consider this is detail the next day in Salem Harbor, but I did note that sighting from the left to the right eye did move my finger from Pig Rock halfway to Princes Head, which on the chart is close to the supposedly universal six degrees. Figure 3: Range to Grape Island and Paddle Ground Track to Peddocks Dock. Observation of Sheep Island against Grape from Peddocks Island. After orienting the chart and understanding our location, I noted that coming back to Houghs Neck from out on the bay can be confusing for people. The coastline will look featureless, and it is important to assess the back view on the paddle out to determine guidelines for the return. Of course, we have West Gut and Princes Head – but those landmarks are still distant from the put- in at the end of a long paddle. The key feature that pinpoints the public ramp is the topography of Houghs Neck. It is a very well defined hill of probably 100 feet height; and the ramp is just south of the hill. Everyone agreed that despite the many land and water features, Boston Harbor is no place to be without a chart. We launched around noon and headed north towards Peddocks. Our choice of mid-April for the paddle had a lot to do with expected boat traffic. As we were paddling up Houghs Neck a freighter and pilot boat were moving from the Fore River to Hull Gut. They were much too fast for us to catch up and intercept them in the gut. This was unfortunate as it would have been quite a sight! As we passed Pig Rock and the nearby daymarker, it was noted that the Pig and its Piglets were safe zones for kayakers crossing in mid- summer among a lot of boat traffic. During the day we defined safe zones – locations where paddlers would likely not encounter boat traffic. Except for one small but significant incident later in the Hull Gut, there were no more boats present during our paddle. We crossed West Gut after the ebb had started (see data sheet Plot #1) and first attempted to use the Hull Gut windmill against Prince Head as a transit. The problem was that the angle of the crossing was moving the windmill even if you paddled on the desired straight line. A more useful transit was formed by the edge of Prince Head against a large structure on Hull. After crossing on the transit we went to the east side of Prince Head. During a break there, we discussed the “Rule of 30”, namely that the boat angle on a transit is a measure of the current. In the crossing, I noted that at the peak current, my boat angle was about 15 degrees. A 30 degree boat angle for a 3kts paddler corresponds to 1.5kts current, so 15 degrees would counter .75kts of current. Certainly, it was no more than one knot. The ebb was probably closer to .5kts at this time so it was an over-estimate, but there were other factors such as the NE wind that may have been quartering at some points. Also, we were not making three knots on the crossing. At Prince Head we first encountered the “Hull Lighthouse”, a prominent vertical tower on Hull that looked just like a lighthouse. Some people thought they could see lights flashing from it, although on this trip I did not. We stopped to take a 90M bearing to the “lighthouse” from the Prince headland. This became a post-paddle discussion point described in Appendix B. As we progressed up the east side of Peddocks, we checked lobster buoys for the current which seemed slack. A member of the group noted a single moored sailboat pointed northeast, indicating a southwest flow. There was a slight NE wind, but it was weak and shadowed at this point, and it is known that moored sailboats are more impacted by current than wind (due to the keel). Hull Gut was heading for maximum ebb, and the effect could have been back-flow in the consequent eddy. West Gut had already started the ebb, which would contribute to a southwest flow. I decided that the evidence for a rotary current at this location would require much more sustained observation. Landing at the docks on Peddocks, I took a 105M bearing to the “lighthouse” after walking down the beach. We then worked on the problem of finding Sheep Island in Hingham Bay.