surfing trawlers

[seattleboatguy]

I looked at a couple trawlers for sale over the weekend. One had a lot more horsepower than the other. When I asked the broker if the bigger boat was over-powered, he said it depended on how you use it. During that discussion, he said something I had not considered before. He said that if you have enough horsepower, when you come in off the ocean and head for the jetty entrance, you can keep up with the swells. I guess the theory is that you adjust your speed so you stay in back of the swell in front of you, and you don't allow the swell behind you to overtake your boat. Do trawlers actually do this sort of thing, and if so, what speed is required?

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[psneeld]

In my exprerience with trawler speeds and towing speeds between 5 and 10 knots.through a breaking inlet....it is very rare to be able to keep up with the swells.

Once they are large enough to worry about..most of the time they are moving faster than 10 knots.

I think the formula is something like 1.5 X the swell period...so a 6 to 7 second period is already near 10 knots.

 

[dimer2]

There is a bunch of effort that goes into the design of most trawler sterns that say this is not possible, even at sea where the wave periods are a lot longer than in shallow inlets. We used to routinely surf the back of waves coming back to the beach in South Africa, where beach launching is pretty standard. This was in 17 ft twin outboard fishing boats and we would be doing 14 - 16 knots coming in between swells, if memory serves me well.

 

[caltexflanc]

If the so-called trawler is capable of the speeds... meaning it is a planing hull of some type, then yes. The Hatteras is way over powered for our usual 9 knot-ish speeds, but boy does that power come in handy in a bad following sea, especially such as one stacked up by the ebb in an inlet (which I try to avoid at all costs). Then throttle control is the whole game.

 

[kchace]

The best way to handle waves when crossing a bar is to indeed ride the backside of the waves. We keep our boat in a river well known for a bad bar crossing. When the tide is ripping out and there is ANY incoming swell component, the waves stack up and at times can be very bad. There is just enough reserve power in our boat that I can pretty much keep up with the waves. Not only that, but the extra speed gets the bow up and stiffens the ride so we are not a bobbing cork at the mercy of the waves. It is a huge help in handling our bar crossings.

Ken

 

[seattleboatguy]

There is just enough reserve power in our boat that I can pretty much keep up with the waves.Ken

Hi Ken. If a 38' Marine Trader had the same twin Lehmans you have, would that boat also be able to keep up with the waves, or would it get into trouble because of its shorter length?

 

[psneeld]

It all dependes...waves travel at different speeds so you need to also.

In my experience...unless you have something other than a displacement trawler, keeping up with storm sized waves is out of the question and even some semi-displacement vessels can fail to keep up.

 

[psneeld]

Right now my inlet is 4 to 6 footers...stacked a little tighter than normal on the 3 knot outgoing tidal current.

The offshore buoy is calling the swell and wind wave combo at 8 second period.

At 8 seconds and 6 foot...no real threat to my 40 foot trawler almost no matter what.

With the 1.5 time 8 seconds to come up with swell speed...they are thavelling at 12 knots...almost 2x as fast as I go...at least 1.5 times as fast as I can go.

If the weekend Nor'easter had produced bigger waves with a longer swell...thevinlt would be interesting for me and then the waves might be 3x faster....so no surfing them unless you have an 18 knot boat or so.

 

[Larry M]

Hobo's FD. This picture was taken from a jet ski as we were crossing a river bar at high slack. We were at WOT as the waves passed underneath us. More speed I think would have added more excitement. You didn't want to get sideways no matter how fast you were going.

 

[kchace]

Hi Ken. If a 38' Marine Trader had the same twin Lehmans you have, would that boat also be able to keep up with the waves, or would it get into trouble because of its shorter length?

Shorter length doesn't help. It means you reach hull speed at a lower speed and it makes it easier to be pushed off course as you surf the waves. Whether you can go fast enough really all depends on the speed of the waves which can vary dramatically. In the case of the bar I'm talking about the waves move a bit slower than average due to them being pushed together by the current. Frankly I was a bit surprised (and pleased) that pushing the throttles got me the speeds I needed to vastly improve my bar crossings.

Ken

 

[GFC]

If the weekend Nor'easter had produced bigger waves with a longer swell...thevinlt would be interesting for me and then the waves might be 3x faster....so no surfing them unless you have an 18 knot boat or so.

I've never had the experience of running the waves coming into an inlet when I was driving. I did as a passenger when we took that boat from Seattle to San Francisco a couple of years ago.

The closest we've come was coming up the Columbia a couple of years ago running on plane against a 2-3kt current with a 25kt wind on the stern. That gave us 5' waves directly on the boat. Dang, that was a fun ride.

I'm anxious (and a bit nervous) about doing it even though we have plenty of power and a 22kt planing speed.

 

[Scary]

Slow trawlers just don't have enough speed

Fast semi displacement boats with smaller rudders need to use this technique of riding the back of wave to control their tendency to broach. Slower boats with large rudders are forced to deal with following sea conditions sometimes by tacking down wind. Stabilizers really help these slower boats track. My boat doesn't surf in the conditions I'm willing to go out in, but it does get a fuel saving push from the wind and the waves. One of the big problems with surfing is catching the next wave and stuffing your bow. The results can be very dramatic, usually a broach and possible roll as the following wave catches your stern as your boat goes stage right or left . If your planning on surfing your big hp is a positive asett. You haven't lived until you stuff a ,57' boat at 24knts into the back of a 20' wave.

 

[psneeld]

at some point you can't outpower the waves and ride them...

then you just have to wait and see if you still have control...which you probably will for a bit....

then it is time to be bow into them if you can or be trailing a drogue...unless you or your boat has a better survival tactic.

 

[Larry M]

The guy on the jet ski was our pilot to get across the bar. You could only get in or out once per day at high tide if and when the winds were light. You can see the breaking waves behind us. It was a bit of a white knuckle ride.

 

[caltexflanc]

Hobo's FD. This picture was taken from a jet ski as we were crossing a river bar at high slack. We were at WOT as the waves passed underneath us. More speed I think would have added more excitement. You didn't want to get sideways no matter how fast you were going.

That looks like very benign conditions; I'd love to have that with every bar crossing and inlet entrance. It's when the waves start to approach your freeboard (or even half way with a wide flat ass boat like the Hatteras) that the pucker factor should kick in.

An additional issue with inlets of course, is that they are narrow, and narrower yet with boat traffic coming in and out (or as they like to do in the Carolinas, guys fishing in the middle of the channel). So tacking or turning around is almost never an option. Slack before flood being the best time, anything with "ebb" in it to be avoided, the more ebb the worse, all multiplied many times over if the wind is against the tidal current. If the inlet is the "outlet" to a significant river system (Columbia, Golden Gate, Caper Fear for instance) is another amplifying factor. Note that we are referring to the current not the tide height stage.

Another example of "the most dangerous thing you can have on a boat is a schedule". Unless your schedule takes these factors into account.

 

[seattleboatguy]

Slack before flood being the best time, anything with "ebb" in it to be avoided, the more ebb the worse, all multiplied many times over if the wind is against the tidal current.

I would have thought that slack before ebb would be the best time due to the increased water depth. Why is slack before flood better?

 

[psneeld]

Depends on the inlet.

Some you need water over the bar to even get in and generally with more water the breakers might be different....

Some have small bascule bridges at the beach where any flood is definitely less desirable...especially with a swell pushing you towards the bridge.

Ebb seems to be worse in many inlets but may not be worse enough to overcome other issues...it will certainly help stack up the swells.

Running any breaking inlet is never wise without a little local knowledge. Look at the cruising guides and note how many inlets are regularly used by locals yet are labeled "not recommended".

 

[MurrayM]

Always thought these Burke Seabrake anti surfing/broaching devices looked really good for controlling ones arse end in conditions we're talking about;

Seabrake | Burke Marine

The conditions here in Douglas Channel can be dangerous for the uninitiated. It's a 60 mile long twisting channel studded with large islands that cuts into the Coast Mountains and is subject to brisk afternoon inflow winds in the spring and summer, strong outflow winds in the winter, and lines up with southwesterly storms in the fall.

It's the islands and steep shorelines that make it unpredictable for those who aren't used to it. On one side of an island the channel can be very curvy which doesn't allow large waves to form, but the other side could have 10 miles of fetch.

The larger waves bend around the end of the island, and now you're into waves crossing each other at about a 30 degree angle...but it can get worse...because those two waves sets sometimes bounce off of steep rock wall shorelines and now there are waves coming from 4 directions

We've seen it so bad that it caused what we called 'haystacking', where the wave formed pyramids which grew so fast and tall that their tops exploded into spray...made for an exciting rodeo ride in our sea kayaks!

If it's not too bad, our method is to try and line up the next piece of channel or bay at a comfortable angle and stay in the trough...or speed up slightly and slide sideways through the trough to get a better angle...or if it's really confined we sometimes wait for a flat spot to turn and take it diagonally on the bow, then turn again when it's a straighter shot downwind...or some such combination.

Like psneeld said; there comes a time when you stop playing with the waves because they're starting to play with you. The trick is to bail into a bay and anchor before that happens.

 

[psneeld]

Steep ocean waves are one thing...till you get into truly strong gale conditions they are annoying but haven't presented much of a threat unless against the current or as Murray suggested from different directions and amplified in magnitude.


Breaking waves from shallowing water are another whole animal as their faces will vetical and roll more so than the crumbling tops of ocean waves.


I know not very technical...but I would rather be in 16 foot ocean waves (up to gale force or so) than 8 foot breakers in my trawler....even 4 foot breakers would make me squeamish.

 

[caltexflanc]

Depends on the inlet.

Some you need water over the bar to even get in and generally with more water the breakers might be different....

Some have small bascule bridges at the beach where any flood is definitely less desirable...especially with a swell pushing you towards the bridge.

Ebb seems to be worse in many inlets but may not be worse enough to overcome other issues...it will certainly help stack up the swells.

Running any breaking inlet is never wise without a little local knowledge. Look at the cruising guides and note how many inlets are regularly used by locals yet are labeled "not recommended".

Personally I am not crossing any bar that won't comfortably float my boat at low to mid tide. I like the challenge of going into and out of secondary and some tertiary inlets, but a man's got to know his limitations. And, we are pleasure boaters, in that order. You sometimes are faced with having to go in at an unideal time, say some sort of emergency, so it pays to know what to do if so, to mitigate the danger.

I'd agree on the few places with a draw bridge over the inlet (Longboat Key, which I've been through and Shark River NJ, which I haven't, come to mind) but on the other hand I'm going to stand well off to begin with until they are ready to raise it. Regardless, if an inlet is tricky, just call me a "slacker".

 

[MurrayM]

Steep ocean waves are one thing...till you get into truly strong gale conditions they are annoying but haven't presented much of a threat unless against the current or as Murray suggested from different directions and amplified in magnitude.


Breaking waves from shallowing water are another whole animal as their faces will vetical and roll more so than the crumbling tops of ocean waves.


I know not very technical...but I would rather be in 16 foot ocean waves (up to gale force or so) than 8 foot breakers in my trawler....even 4 foot breakers would make me squeamish.

There are a couple spots in the middle of Hecate Strait that are 6 fathoms...imagine what a horror it would be seeing a wave bottom out and explode right in front of you, in the middle of nowhere.

 

[psneeld]

If my oceanography understanding is accurate...6 fathoms would start to stack up a wave with a period of 18 seconds ....a long fetch wave of 18 seconds would have a height of 12 feet.


Believe me...these are rough rules of thumb I have remembered through the years so any oceanographers or more educated plese help as this seems a bit out of what Murry would be seeing.


Wow...it sounds like you must get some pretty drastic wave formation and cruising conditions in those straights.

 

[Wxx3]

Hobo's FD. This picture was taken from a jet ski as we were crossing a river bar at high slack. We were at WOT as the waves passed underneath us. More speed I think would have added more excitement. You didn't want to get sideways no matter how fast you were going.

You were on a surfing safari