Which ramp you back down decides the kind of day you get. Lake Champlain is 275,917 acres of open water in this pack, enough fetch that the afternoon wind builds a real chop and the far shore is a crossing rather than a glance. Back down at Lake Bomoseen instead, 2,397 acres, or at Lake Dunmore at 1,038, and you can see most of your day from the ramp. The question changes with the water. On the big lake it is when to go out and when to come back in. On the small ones it is how thin it gets over the bar off the point.
The Vermont pack carries 1,178 charted water bodies. Of those, 861 have a name on the chart, and 62 of the named lakes are over a square kilometer, which is a shade under 250 acres. The other 799 named ones sit below that mark, which is most of the pack by count: water with a gravel pull-off rather than a paved ramp. All of it is charted water in Helm, with contours and a depth number on it, read against the draft you entered once.
Lake Champlain is the largest water the pack carries, 1,116.6 square kilometers, or 275,917 acres measured off the chart polygon itself. Nothing else in the pack is near it. Lake George comes next at 28,392 acres, which is under a tenth of Champlain, and Lake Memphremagog follows at 23,500. Add the nineteen next largest lakes together and they come to 326.7 square kilometers between them, less than a third of Champlain on its own.
Below the top of the list things tighten up fast, and that is where most of the pack lives. Seymour Lake is 1,754 acres and Lake Willoughby is 1,730, which puts 24 acres between them. Harriman Reservoir and Lake Francis match to the tenth of a square kilometer at 1,927 acres each. Great Averill Pond is 840 acres, within 25 acres of Waterbury Reservoir, so the word pond in a name up here tells you nothing useful about what you are launching onto.
| Lake | Charted surface area |
|---|---|
| Lake Champlain | 1,117 km² (275,917 acres) |
| Lake George | 115 km² (28,392 acres) |
| Lake Memphremagog | 95 km² (23,500 acres) |
| Sunapee Lake | 17 km² (4,102 acres) |
| Moore Reservoir | 13 km² (3,262 acres) |
| Lake Bomoseen | 10 km² (2,397 acres) |
| Harriman Reservoir | 8 km² (1,927 acres) |
| Lake Francis | 8 km² (1,927 acres) |
| Seymour Lake | 7 km² (1,754 acres) |
| Lake Willoughby | 7 km² (1,730 acres) |
| Tomhannock Reservoir | 7 km² (1,705 acres) |
| Somerset Reservoir | 6 km² (1,507 acres) |
The twelve largest named lakes the Vermont pack carries, by charted surface area, measured from the chart polygon itself. The pack carries 1,178 charted water bodies in all, 861 of them named, and 62 named lakes larger than one square kilometer.
NOAA surveys the coast and the result is a nautical chart. Somerset Reservoir does not get that, and neither does Lake Bomoseen. Inland, Helm builds the chart from two other sources. The water bodies themselves come from the National Hydrography Dataset, the national record of where the water actually is, and the depth under them is built from state elevation surveys of the ground the water sits on.
That pairing is the whole difference between a lake you can plan a run across and a blue shape with a name floating in the middle of it. Once there are contours and a depth number on the water, you can draw a line from the ramp to the far end and read it against your own draft before the trailer is hitched. How depth shading and draft aware routing work in general is covered on their own pages. What matters here is that on all 1,178 of these water bodies there are real numbers underneath them.
An elevation survey measures ground. On a reservoir that ground spends its life under a pool held at whatever level it is being held at that month, and the survey does not ride up and down with the pool. Read a contour on one of these as the shape of the basin rather than as today's water, and carry the current level as an offset on top of it. Anybody who has launched on the same reservoir in June and again in October is already doing this without calling it anything.
The useful part is that the shape does not move. The old creek channel running through the middle of a flat is in the same place at any level, and the shoulders on either side of it are the ground that goes from crossable to not. Enter your draft and those shoulders shade, which is the thing that tells you to hold over the channel while you still have room to turn.
Five of the twenty largest lakes the pack carries have Reservoir in the name:
The packs are cut to a box rather than to a state line. A lake on a border therefore turns up in more than one pack, whole in each of them. That is why this one carries the full 275,917 acres of Lake Champlain, all 23,500 acres of Lake Memphremagog and Lake George at 28,392, along with Sunapee Lake at 4,102, Lac Lovering at 1,186 and Mascoma Lake at 1,137.
For a trailer boat this is worth sorting out in the driveway instead of at the ramp. The New York, New Hampshire and Massachusetts packs overlap this one along their edges, so a border lake comes with whichever of them you already have on the phone. Download the pack that covers the rest of your season and the water on the line comes with it.
Inland lake depth comes from state elevation surveys rather than from nautical charts, and a reservoir sits at whatever level it is being held at that week. Treat the shape and the depth as a guide, keep a lookout, and verify locally.
Depth data. Champlain is the largest water the Vermont pack carries, 275,917 acres, and the depth under it is built from state elevation surveys rather than from a nautical chart, so the lake has contours and a depth number on it. Enter your draft and the water your boat cannot take shades on the screen.
Lake George at 28,392 acres and Lake Memphremagog at 23,500 are next, then Sunapee Lake at 4,102 and Moore Reservoir at 3,262. Further down the list are Lake Bomoseen at 2,397, Seymour Lake at 1,754, Lake Willoughby at 1,730, Lake Carmi at 1,408 and Lake Dunmore at 1,038. The pack carries 1,178 water bodies in total, 861 of them named.
Read them as the shape of the basin. They come from an elevation survey of the ground, so they stay put while the pool moves, and the level the reservoir is being held at works as an offset you carry on top of them. The old channel through a flat is in the same place at any level, and with your draft entered it is the shoulders on either side of it that shade.
Helm Boating