NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Silicon Sea: Leg 76
From: Michael Wescott
Date: 2001 Jul 09, 12:06 PM
From: Michael Wescott
Date: 2001 Jul 09, 12:06 PM
> We then motor to the Isla Flamenco and anchor at(08d 55.2'N 79d 31.6'W) to do > the final trip planning, servicing, and provisioning the boat. We will motor > from our anchorage to abeam the Light at Isla San Jose(08d 10.5'N 079d > 15.0'W). Speed 8.3 Kts. Our departure is planned for sunrise on 24/06/2001. > > 1) What is the Zone Time(ZT) of sunrise at our anchorage? > What is the UT/GMT time of Sunrise? > -- ------------------------------------------------------ Anchorage at 08d 55.2'N 79d 31.6'W. Sunrise on 24-Jun-2001 will be shortly after 0541 LMT. LMT is 4d 31.6' West so we add about 18 min to get ZT. And for GMT we add 5 hours. A close enough answer is 0600 ZT (GMT+5) 1100 GMT Wow, sitting in the Pacific further east than where I'm sitting now (Columbia, SC). > 2) What is the TC and Distance from Our anchorage(08d 55.2'N 079d 31.6'W) > to abeam of Isla San Jose Light(08d 10.5'N 079d 15.0'W)? > -- ----------------------------------------------------------------------- Reading directly from the chart (or plotting sheet, in this case) C = 160T D = 47.6 > It is late in the season and the North Pacific storms are beginning so we > elect to bypass the Galapagos Islands. We will follow the recommendations in > Ocean Passages For The World and in World Cruising Routes and on departing > Isla San Jose Light(08d 10.5'N 79d 15.0'W) we will head for a Mid-Ocean > Point(MOP) at (03d 00.0'N 110d 00.0'W). Why so far south? To avoid the storms? Don't we risk light winds so far south? > 3) What is the TC and Distance to the MOP at (03d 00.0'N 110d 00.0'W) > from Isla San Jose Light(08d 10.5'N 79d 15.0'W)? > -- ------------------------------------------------------------------ Using M.P.: C = 260.4T D = 1861.9 Using M.L. (5d30'): C = 260.4T D = 1862.6 Using GC: IC = 262.1T D = 1861.5 > From the MOP(03d 00.0'N 110d 00.0'W) we head to make landfall on the > Southwest coast of Hawaii(19d 30.0'N 154d 45.0'W). We have two alteratives > depending on current and weather, either a Great Circle Course or the Rhumb- > Line course. > > 4) Calculate the Rhumb Line TC and Distance to landfall. > Calculate the Great Circle initial course and Distance to landfall. > -- ------------------------------------------------------------------- Rhumb Line (M.P.): C = 290.5 D = 2820.2 Great Circle: IC = 294.2T D = 2801.1 > 5) To the nearest tenth of a day, what are the total days enroute from our > anchorage at Isla Flamenco to the Southwest coast of Hawaii as our plan is > layed out? Sailing Speed 9.5 Kts, motoring Speed is 8.3 Kts: > > Isla Flamenco (08d 55.2'N 79d 31.6'W) > Isla San Jose Light(08d 10.5'N 079d 15.0'W) > Mid-Ocean Point(MOP) at (03d 00.0'N 110d 00.0'W) > Southwest coast of Hawaii(19d 30.0'N 154d 45.0'W) > -- ------------------------------------------------------------------------ For planning purposes we'll use the longest (Rhumb Line) and slowest (8.3 knot, 199.2 nmi/day). Leg 1: 47.7 Leg 2: 1861.9 Leg 3: 2820.2 ============= Total 4729.8 which is 23.7 days > Having a 6 person crew and water consumption at 1.5 US Gal/day per person. > > 6) What is the expected water consumption for the trip to Hawaii? > -- -------------------------------------------------------------- 213.3 gal > 7) Estimating 3lbs of food per day per person what is the total weight > in food for the trip? > -- ------------------------------------------------------------------- Twice the water. 426.6 lbs. -- Mike Wescott Wescott_Mike@EMC.COM