Learning to Deal With Tides

[CollinR]

Have a look at the Dinghy Cruising Association - dinghycruising.org.uk - they do exactly what it says on the label, but mostly on the leeward side of the pond. Tides around the UK are not inconsiderable, the Bristol Channel manages the second highest in the world, the Solent gets two high tides every twelve hours and the Corrie Bhreachan in full flow has to be seen to be believed.

Dwedais "Gwirion", nid "Twp"

[signalcharlie]

This seems to be an updated reference, Captain Q mentioned it during one of his videos.
A CRUISING GUIDE TO THE MAINE COAST - 6TH ED.

• complete coverage for every harbor and anchorage
• exacting navigation advice
• overview and detailed sketch charts
• advice on cruising in Maine: tides, fog, lobsterboats
• detailed shoreside activities and amenities: hiking, exploring, dining
• Maine history and natural history
• emergency numbers, advice, and harbors of refuge

As for gear and other small boat ideas you browse through Small Boat Magazines Product Review and Techniques articles.

And I'd consider joining the Small Reach Regatta facebook group, they'd have a lot of regional specific advice.

Good luck!

[Canoeyawl]

A lot of the Maine coast looks like this.
(check your pm's)

Saturday Cove looking east at Islesboro, across the west branch of Penobscot Bay
Tides in
15C9E589-DD37-46D0-B23E-7A200992EF89.jpeg

Tides out
9BAD2522-20B8-4BA5-BF56-C3E10A2A459E.jpeg

[Ian McColgin]

Tide rise and fall is not always even. You may see a pause in the ebb or flow. Nor is exactly sinusoidal. Nor is there exactly six hours from one slack to the next But the amount of change for any given span can be reasonably approximated by the "Rule of Twelfths"

During the first hour after slack the depth will change 1/12 of the total tidal range.
Second hour 2/12.
Third hour 3/12.
Fourth hour 3/12.
Fifth hour 2/12.
Last hour 1/12.

Here on Nantucket Sound the range is only 4' so I just convert to inches - first hour 4", 2nd 8", third 12", fourth 12", fifth 8", last 4". For a place like Portland Maine with more like a 10' tide range, I go in my head as a 12' tide and knock each hour back about 15%. Easy in your hear arithmetic and saves you from a spurious sense of precision that may come from using a calculator. This is all approximate and based on models that ignore local reality.

Since there are many places where there's a tidal current but no hourly current chart, this gives you a useful clue as to when the flood or ebb will be strongest. And of course knowing that fully half of whatever the tide range is happens in the middle two hours will tell you what to do or not do when running aground.

[chas]

I consider the Discovery Islands my home cruising grounds, although we are away from there at the moment. Running through my charts yesterday, I noticed the large scale chart of currents through the Yaculta and Dent Rapids. I thought of this thread Tom and snapped a pic which I'll try to download here. In the meantime here is a nice video which gives an idea of conditions there at both slack and high water flow. This is the one set of rapids out here I have yet to transit in one tide cycle, and if it remains unconquered, so be it.
Both the chart and video illustrate the flow and strength of back-eddies, which are indispensable when navigating these types of coastal waters in slow boats. / Jim

[John Meachen]

I hesitated to mention it, in case it could be a deterrent,but Tom might learn a few things from Frank and Margaret Dye's records of their voyages.Calling your book "Sailing to the Edge of Fear" might not be the best way to recruit sailors to small boat cruising even though it does admirably describe the details very well.

[WI-Tom]

Thanks again, everyone--interesting stuff. I've read the other Dye books, but not the "edge of fear" one.

Tidal eddies look similar to the eddies I've rowed past/though/into/out of in the Grand Canyon.

The reminders about the rule of 12s are very handy, too.

Tom

[P.I. Stazzer-Newt]

The rule of twelfths also applies to current speeds - but 90 degrees out of phase.
Linear interpolation is useful for secondary port calculations.

If you're not naturally comfortable with vector calculations then the way tidal current can influence tack choice is interesting

https://www.pbo.co.uk/seamanship/nav...-defined-41887 <- nice explanation.

[Nicholas Scheuer]

I was in your situation exactly, Tom some twenty years ago but ended up greatly enjoying a week-long cruise on Penobscott Bay in our 28' Shearwater Yawl. I used to be a dedicated paper chart and magnetic compass guy. While still in that state we enjoyed another week-long cruise to Desolation Sound on the "sunshine coast" of BC, where the tides are even higher than in Maine. I had heards E Coast sailors talk of "Eldridges" and thought they might be talking about some sort of fowl weather gear. While moored at one of the Elizabeth Islands in Vineyard Sound another skipper showed me his Eldridges Tide Tables, which we did not have. We've recently installed a Garmine Echomap in our boat, but not having GPS never got in the way of enjoying cruises on all of the coasts surrounding the USA.

So, how would a Great Lakes sailor who has rarely had to deal with tides of any kind learn to do so?

Let's imagine, say, that those pesky Canadians are likely going to keep their border closed this summer, shutting off access to tide-free cruising. ANd let's further imagine that, as a Plan B, someone were to begin thinking about a month on the Maine coast in this boat (which offers options to sleep aboard comfortably, on a raised platform):

Attachment 76957

What would you recommend a guy like that do to prepare for his first-ever foray into serious tidal waters?

What kinds of challenges should he be preparing for that he might not even be aware of?

What kind of gear might he need to add to his kit?

What kinds of books/charts etc. would he need to navigate the Maine coast for several weeks?

What kinds of places and situations might be more dangerous because of tides than a non-tidal sailor might think?

If this guy were philosophically opposed to GPS and electronics, how could he manage without it?

I'd greatly appreciate... Er, this guy would probably really appreciate any thoughts from people experienced with tides, especially tides on the Maine coast in particular.

Thanks!

Tom

[WI-Tom]

The rule of twelfths also applies to current speeds - but 90 degrees out of phase.
Linear interpolation is useful for secondary port calculations.

If you're not naturally comfortable with vector calculations then the way tidal current can influence tack choice is interesting

https://www.pbo.co.uk/seamanship/nav...-defined-41887 <- nice explanation.

Thanks for that--I had vague notions that I knew about at least of the existence of the need for lee-bowing the tide, but that explains it nicely. Something to muse about more, as real-world situations will rarely be so clear, but the idea of "choose the tack that will push you back toward the rhumb line" is handy, as is the vector-induced wind angles.

Tom

[WI-Tom]

I was in your situation exactly, Tom some twenty years ago but ended up greatly enjoying a week-long cruise on Penobscott Bay in our 28' Shearwater Yawl. I used to be a dedicated paper chart and magnetic compass guy. While still in that state we enjoyed another week-long cruise to Desolation Sound on the "sunshine coast" of BC, where the tides are even higher than in Maine. I had heards E Coast sailors talk of "Eldridges" and thought they might be talking about some sort of fowl weather gear. While moored at one of the Elizabeth Islands in Vineyard Sound another skipper showed me his Eldridges Tide Tables, which we did not have. We've recently installed a Garmine Echomap in our boat, but not having GPS never got in the way of enjoying cruises on all of the coasts surrounding the USA.

Thanks--good to know!

How'd you deal with fog without a GPS? Ded reckoning?

Tom

[Ben Fuller]

Thanks--good to know!

How'd you deal with fog without a GPS? Ded reckoning?

Tom

Dead reckoning, its not hard at small row sail boat speeds, and a few tricks like aiming off and handrailing. These are explained in some of the reference books on kayak navigation. Unless you do the mouth of the Kennebec or get up in the Eastport area or find one of the few tidal falls currents may get around 2. And they aren't in any of the books, but are on the GPS aps. The MITA book points out a few other current hazards.

[Gib Etheridge]

If you're feeling intimidated by the amount there is to learn and/or your ability to implement all of the information, as I would be, let me offer a bit of relief. You can get all of the help you need (for a relatively small fee) from any of the manufacturers of 6 HP 4 stroke outboards.

[WI-Tom]

If you're feeling intimidated by the amount there is to learn and/or your ability to implement all of the information, as I would be, let me offer a bit of relief. You can get all of the help you need (for a relatively small fee) from any of the manufacturers of 6 HP 4 stroke outboards.

Get thee behind me, Gib Etheridge!

Tom

[WI-Tom]

My copy of the David Burch "Fundamentals of Kayak Navigation" arrived today--thanks for the suggestion. His view on small boat navigation seems to match my own experience:

...kayak navigation is done from "the seat of the pants"--meaning done in large part by careful looking and trained intuition. Done well, it appears to be not done at all. Although a watch and compass might be at hand, even those are often used by experienced paddlers without conscious thought of navigation. Some paddlers, who have covered thousands of miles in a kayak, have the same feeling that many mariners have--that they do not actually do much navigation underway. But to get by without much navigation requires much skill at navigation.

I suspect that tides will bring an interesting set of complications to the process of "not much navigation," but I'm not starting out as a complete beginner, either. I've got the "thousands of miles" in a small boat, a bit of fog time, and a decent amount of backcountry land navigation.

Again, thanks for all the thoughts here--I really appreciate it!

Tom

[stromborg]

Something to keep in mind about how water moves is that the smaller the passage is the faster it tends to run. There are places out here where unless you have a lot of horsepower and fuel to burn it is better to wait for the tide/current to turn in your favor. The locals should know, pay attention to when they haul up their anchors and head out. Asking another boater is potentially a great way to meet new friends too.

[WI-Tom]

Anyone want to weigh in on which coast has the most challenging tides to deal with--east or west? Maine, or the PNW?

I know some of the big PNW rapids are fearsome, but what about overall? Seems like maybe more narrow passages on the Inside Passage than on the Maine Coast. Not sure about tidal ranges--similar, maybe?

Tom

[AJZimm]

Are there any places on the US eastern seaboard that have circular tidal currents - that is currents that don't have a slack period but simply go round the compass in a cycle, without slowing to a slack?

We have at least one place like that out here, a place not likely to be encountered by the small boater, fortunately - middle of the west entrance to the Strait of Juan de Fuca.

Just wondered.

[Canoeyawl]

Tide at Center Harbor, Maine tonight is 11+feet : https://www.tide-forecast.com/locati...e/tides/latest

For anchoring in and around Penobscot Bay I usually figure a 12 foot drop, which is fine unless there is a rock under your boat. It is nice to have local knowledge.

7C3D0839-2C7D-4E89-A044-730AE92B92CB.gif

[Gib Etheridge]

Get thee behind me, Gib Etheridge!

Tom

Did you mean "Get thee behind me Honda 6!"?

[Ben Fuller]

Anyone want to weigh in on which coast has the most challenging tides to deal with--east or west? Maine, or the PNW?

I know some of the big PNW rapids are fearsome, but what about overall? Seems like maybe more narrow passages on the Inside Passage than on the Maine Coast. Not sure about tidal ranges--similar, maybe?

Tom

There are few places on the Maine Coast that you have to go through that have the currents of the PNW. Much more challenging. Read Alex Zimmerman's Becoming Coastal.

[AJZimm]

Anyone want to weigh in on which coast has the most challenging tides to deal with--east or west? Maine, or the PNW?

I know some of the big PNW rapids are fearsome, but what about overall? Seems like maybe more narrow passages on the Inside Passage than on the Maine Coast. Not sure about tidal ranges--similar, maybe?

Tom

Tom, I've never sailed on the east coast, so can't speak to conditions there, but here in British Columbia, the tidal range gets bigger the further north you go.

In the next couple of weeks, for example, the highest tide here in Victoria, where I live, is a little over 10 ft. At the same time in Prince Rupert, the highest tide is a little over 22 ft. Currents in the long channels to match.

Flood current in Seymour Narrows on January 12th, 5 days ago, was predicted to be over 15 knots.

[Bill Perkins]

Tom ; I remember my excitement when I received my MITA guide book . I wish you joy of your cruise ! I did two trips there , hauling my 120 lb 15 ft. boat up with a pair of fenders tied together at their tops .The boat centered nicely in the cleft between .Untied the pair were jammed forward under the small deck for storage and lashed in place to serve as added flotation when underway .Being able to haul out is one of the big advantages of going small I think .

Not tide related but another piece of gear I found essential was the best quality air mattress ; preferably brand new . Mine was 3/4 length ; looked and felt like canvas ( for back packing ). It was for sleeping of course ; but I discovered the mattress had an important second use when sailing in mild weather . With about half the air let out it could be set athwart with me sitting on one end in the bottom of the boat and leaning on the rest to weather , with a big crease forming a hinge between the 2 parts . This makes a surprisingly comfortable chair .To be comfortable for long stretches' under sail really adds to the enjoyment . When conditions change it's easy enough to stow forward . At the end of the day it was no small thing not to have to inflate the mattress from scratch . This chair is also really nice ashore deployed against a tree or rock . There's allot of rock out there ;take something soft !




.

[WI-Tom]

Tom ; I remember my excitement when I received my MITA guide book . I wish you joy of your cruise ! I did two trips there , hauling my 120 lb 15 ft. boat up with a pair of fenders tied together at their tops .The boat centered nicely in the cleft between .Untied the pair were jammed forward under the small deck for storage and lashed in place to serve as added flotation when underway .Being able to haul out is one of the big advantages of going small I think .

Not tide related but another piece of gear I found essential was the best quality air mattress ; preferably brand new . Mine was 3/4 length ; looked and felt like canvas ( for back packing ). It was for sleeping of course ; but I discovered the mattress had an important second use when sailing in mild weather . With about half the air let out it could be set athwart with me sitting on one end in the bottom of the boat and leaning on the rest to weather , with a big crease forming a hinge between the 2 parts . This makes a surprisingly comfortable chair .To be comfortable for long stretches' under sail really adds to the enjoyment . When conditions change it's easy enough to stow forward . At the end of the day it was no small thing not to have to inflate the mattress from scratch . This chair is also really nice ashore deployed against a tree or rock . There's allot of rock out there ;take something soft !

Bill,

thanks for the post. My boat (Alaska) is significantly heavier--so much so that I doubt beaching will be an attractive option if there are any ways to avoid it. With two people it'd be more realistic, but I generally sail alone.

As for rock--well, I'm used to that. My usual cruising grounds:



The new thing will be how they don't stay the same distance above (or under) the water!

Tom

[WI-Tom]

Thanks to all posters here again--my copy of the Eyges book on piloting arrived in the mail today. Looks great. I like learning from books--I also like how he explains in the preface that this book deals with navigating realistically--what he really does in a small boat, and not what the "standard" navigation classes teach. I suspect he'll be preaching to the choir--and I'm sure I'll learn a lot.

Tom

[dutchpp]

Hi Tom,

for my sailing area which look like this;
waddenzee terschelling.jpg
I use a small program on my iPhone called QuickTime, it can predict with a large amount of accuracy the tides on almost every spot of the map.
Which is necessary because the green parts on the chart dries out during very low tides and we tend to sail over the green parts
There must be something similar available in the US? If not, that could be a great business opportunity for an entrepreneur!

Their website in Dutch only ( it's a specifically Dutch program, but hey it's for free!) https://www.nautin.nl/wb/pages/getij/quicktide-app.php

[Edward Pearson]

Tom,

This is my day sailing small boat passage planning sheet (front and back) I drew up for Solent. Feel free to use, amend or ignore. It's a precis of much pilotage and passage planning info with the aim of guiding me to a smooth daysail and avoiding of rough conditions while pouring over the chart and drawing vectors

A sheet close to hand with the actual tide times and back up navigation bearings in case of electronic failure is good practice, especially when in the thick of it with the aim of moving in the most ideal conditions. Some bits are for filling in, other bits for circling. Anything that isn't intuitively understandable just ask.

Most of the time this would be overkill, but there was a point a few years ago everyone was going to have to carry a passage plan.


Screen Shot 2021-01-20 at 14.45.06.jpg

Screen Shot 2021-01-20 at 14.46.25.jpg

[John Meachen]

Bill,

thanks for the post. My boat (Alaska) is significantly heavier--so much so that I doubt beaching will be an attractive option if there are any ways to avoid it. With two people it'd be more realistic, but I generally sail alone.

As for rock--well, I'm used to that. My usual cruising grounds:



The new thing will be how they don't stay the same distance above (or under) the water!

Tom

Do keep in mind that on a coastal trip you may find your boat getting dropped onto those rocks with a bang and exercise caution.

[Canoeyawl]

A typical Maine "beach" north of Portland, except missing the occasional half-tide round rock the size of a small house...

826C6DFA-0F7C-44BA-B859-905422AD2B55.jpg

[Thad]

I had a friend working on one of the islands in the Mussel Ridge who anchored near high tide and returned later to find his boat suspended between two of those car size boulders.

[Arlc]

Compared to the Maine coast, it looks like we have it easy on the SE Coast. The main things we encounter are tidal flats, razor sharp oyster shells and hurricanes. WI-Tom, perhaps you should consider a trip South.

[Breakaway]

About rocks-- and not Maine-- but same principle that applies from Montauk east.

I used to fish with a guy out of Cuttyhunk,MA, Charlie Tilton. Charlie, a great and gracious man, like many of us once we reach a certain age, would repeat certain things without thinking about it. One such, " Charlie-ism," was a comment about the reef--Sow and Pigs ; or just, "The Pig"-- that we'd fish over.

As the tide dropped, he'd declaim, in his thick, deliberate Kennedy-esque accent, that we needed to take especial care because: " There's more bottom paint on those stones than on all the boats in the harbor."

Nuff said.

Kevin

[nedL]

About rocks-- and not Maine-- but same principle that applies from Montauk east.

I used to fish with a guy out of Cuttyhunk,MA, Charlie Tilton. Charlie, a great and gracious man, like many of us once we reach a certain age, would repeat certain things without thinking about it. One such, " Charlie-ism," was a comment about the reef--Sow and Pigs ; or just, "The Pig"-- that we'd fish over.

As the tide dropped, he'd declaim, in his thick, deliberate Kennedy-esque accent, that we needed to take especial care because: " There's more bottom paint on those stones than on all the boats in the harbor."

Nuff said.Kevin

It was Sow and Pigs that got Wanderer.

[WI-Tom]

We have a Sow and Pigs around here, too, but they tend to stay in the same position relative to the surface. That's them in the background:

S. Benjamin.jpg

[WI-Tom]

Another couple of questions:

Around the Great Lakes, it's very easy to rely almost completely on eyeball navigation and terrain association.

What non-electronic navigational instruments and techniques do y'all find most useful--and most practical from the cockpit of an open boat with a solo skipper--for dealing with tides?

And how common is it to be able to get away with just eyeballing the islands as you sail by?

Tom