SD v FD in weather

[psneeld]

West Coast is more accurately predicted?


I was always told by weather people that the East Coast with tens of thousands of weather stations coast to coast gave them and modeling a much better picture than the scant info on the West Coast.


It may have swung back...but I still see the advantage going to the East.

 

[mvweebles]

West Coast is more accurately predicted?


I was always told by weather people that the East Coast with tens of thousands of weather stations coast to coast gave them and modeling a much better picture than the scant info on the West Coast.


It may have swung back...but I still see the advantage going to the East.

Weather is pretty reliably forecast along the west coast, and the patterns are pretty consistent (albeit severe at times). There are three primary zones - straits to cape Mendocino, cape Mendocino to Pt Conception, and then southern California. There is definitely severe weather - a couple weeks ago there were 12+ meter seas pounding the northern section for a couple weeks, which isn't unusual in winter. But they are generally well predicted. The seasonal changes are also pretty consistent. Not always good weather, but generally know what you're getting into without surprises. For example, summer pattern is around 25kts-30kts in the afternoon, dying around nightfall to a pretty quiet evening. I knew that if I saw white caps before 11am (~17 kts), winds could go to 30kts-35kts and would be a long, long day.

Peter

 

[Fletcher500]

Regarding big waves, a few weeks ago at Mavericks, NoCal. The Vid is worth watching whether you surf or not.

 

[Hippocampus]

The bride and I envision the future program to primarily be long coastal hops. Leave Florida and next stop the Chessie. Then Naragansett. Then Maine. Of course with interludes of local cruising and just hanging out. We’re back and forth on “real” passage making having been there done that but it still holds appeal. So far have kept the water out, souls in and got there. Many of the above posts have been extremely informative but are more germane to a different program. Know from experience what the clues are for when a multi or mono is overburdened. Know to take the boat off AP periodically and can rapidly sense when to reef, change course , change tactics or invoke storm protocols. What are the clues for you? What are your go to tactics? Are the clues different for SD v FD like they are for mono v multi?

 

[rslifkin]

In pretty much any powerboat, the clues that it's time to do something different will be one of the following, depending on the situation:

• Excessive rolling
• Excessive pitching
• Pounding or slamming into waves
• Excessive yaw going downwind
• Frequent near full rudder input required to maintain course

Depending on the situation, first steps of corrective action may be a course change, a speed change, trim change (on a faster boat), or a combination of those. And as others have mentioned, the idea of tacking rather than heading directly to your destination is not exclusively the realm of sailboats. It's a good way to reduce rolling in a beam sea in a powerboat, although the tactics for making the turn in rough seas when you're ready will depend on the handling tendencies of the boat in question.

With the pitching and rolling cues, you'll usually find the situation getting unpleasant and want to do something about it long before it's dangerous. And for the most part, these cues will be perceptible without even disengaging autopilot (if in use).

 

[Hippocampus]

Do people shift fluids or change volumes? Have found in past with prior boat having 4 fuel tanks and 2 water tanks that was some times helpful. Of course trying to keep tanks either full or empty to reduce surface effects.
Also found shifting heavy stores (if it could be done safely and have them truly secured) was sometimes worthwhile. Is that done?

 

[rslifkin]

Do people shift fluids or change volumes? Have found in past with prior boat having 4 fuel tanks and 2 water tanks that was some times helpful. Of course trying to keep tanks either full or empty to reduce surface effects.
Also found shifting heavy stores (if it could be done safely and have them truly secured) was sometimes worthwhile. Is that done?

Generally location of stuff would be determined based on what keeps the boat well trimmed, but I personally wouldn't start moving stuff around to re-trim based on weather. For tanks, depending on where in the boat they are, it may make sense to use 1 tank first to reduce trim effects. In my case, my fuel tanks are pretty far aft and only 2 tanks (and 2 engines), so I have choice, the stern lightening as I burn off fuel is just the nature of the boat.

 

[mvweebles]

Do people shift fluids or change volumes? Have found in past with prior boat having 4 fuel tanks and 2 water tanks that was some times helpful. Of course trying to keep tanks either full or empty to reduce surface effects.
Also found shifting heavy stores (if it could be done safely and have them truly secured) was sometimes worthwhile. Is that done?

I'm having difficulty finding a difference in how I'd move a SD vs FD boat over a distance. So I asked myself - what are the chances of going from St Pete FL (my home) to Cancun (~400 nms), a stretch I have studied? Weather looks surprisingly decent over the next week or so. Whether I had a GB42 or a N40/N43, I'd leave tomorrow morning and expect 2.5 days. No difference.

Now, let's say my ultimate destination was Rio Dulce Guatemala, 850 nms from St Pete - Cancun is the halfway mark. Early next week, seas are expected in the 3-5 foot @ 5-8 seconds from the east - right on the beam. Workable but uncomfortable on either boat.

But, due to range, if I were running the GB42, I'd have to stop for fuel somewhere in the Cancun area which would mean checking into Mexico and take at least a day - probably two. With the N40/43, I could keep going.

In short, I think we agonize over "the boat" way too much. The limiting factor in my hypothetical trip above is available time, seamanship skills and experience. There are a LOT of boats that can make this trip, but not many boat owners.

Peter

 

[Solly]

I think talking about weather you have to include the effect that the weather has based on the location. A breeze in open water might not be as bad as one funneled thru a bottleneck. Same 20kt wind. Or wind over tide.
2nd is your level of comfort. I'm pretty sure I'll become uncomfortable b-4 the boat will be in any danger.
3rd in general a SD can become a FD based on speed but not the other way around. In our size range I don't believe there's all that much difference in how they would handle weather given equal size.

 

[AusCan]

Every boat behaves a bit different from others. My FD hull rolls like no other in a beam sea without stabilisation but the sails sort out that problem quite well. With the canoe stern, it behaves very well running with the swell, as long as the waves aren't breaking. Other FD hulls with a square transom aren't quite so predictable with the swell pushing the stern around.

I do adjust my load (usually fuel and water) if I have a long run with a beam sea by keeping the tanks on the windward side full. It reduces the heel and helps improve SOG a bit. I sometimes reduce the load in the vee-berth to get the nose up if I plan on pushing into the swell for the day. But my main concern if rough weather is expected is to ensure everything is secured 100%. I don't like dealing with things coming loose and sliding around a boat when dealing with an angry sea.

Solly - An SD hull can slow to FD speed, but the shape and centre of gravity cannot be changed. These are the advantages an FD hull has is heavy weather. We put up with the slow speed knowing it might get rough and nasty, but the boat will keep us safe.

 

[mvweebles]

Reading AusCan reply reminded me that I delivered 7 or 8 N46s, all uphill from Dana Point to WA/OR. Early on, the tanks were quite a bit aft. First one had full fuel tanks and squatted quite a bit. The N46 was a bit fine in the bow to begin with, with a lot of flair so a fair amount of reserve buoyancy. Combination of which meant she was pretty bouncy in a head sea until she'd burned off several hundred gallons. Consequently, I tried to deliver future boats with half load of fuel. Much more comfortable.

Doesn't fully address Hippos premise about shifting load for conditions, and certainly is boat specific, but is the only big example I can think of beyond simply trimming the boat.

Peter

 

[DDW]

West Coast is more accurately predicted?


I was always told by weather people that the East Coast with tens of thousands of weather stations coast to coast gave them and modeling a much better picture than the scant info on the West Coast.


It may have swung back...but I still see the advantage going to the East.

With satellite and fine grained whole earth modeling, the west coast has an advantage: any systems travel thousands of miles across the Pacific over featureless ocean. East coast the fronts come all the way across the continent, disturbed by convection, arctic flow, all kinds of variables. No squalls and not much "local" weather in the west. There are known wind funnels here and there, but again quite predictable.

 

[Hippocampus]

Thanks for the benefit of your insights. So far this thread has been very helpful. Do notice on the SDs we’ve toured although lockers are more commonly latched floorboards and constraints on shelving not so much. We’ve had latches even on compartments with vertical access under the settees cushions installed. Before passage would stuff pillows or bedding into any residual space in lockers so there was no possibility of things shifting. Thinking was you don’t need a knockdown for things to get moving or even flying. Do you have similar concerns? Have you made modifications to prevent this? Do you routinely prevent chairs or other seating from shifting by a modification before leaving?
When storing things always tried to put the heavy stuff close to the center and low. For a given LOA power tends to be much heavier than sail. Especially for FD boats. Outbound46=30k lbs. N40=50k lbs. Do you have a similar concern about gyradius and heavy ends with your boat or is the impact so minimal as not worth worrying about?

 

[psneeld]

Interesting read on weather forecasting difficulty around the nation......

It does mention what I've heard....below is from a couple articles.

"Forecasting in California is challenging?

Hear me out on this.

First, consider the still relatively data void area upstream known as the Pacific Ocean.

Data from satellites and trans-Pacific flights does help numerical forecast models, but the lack of surface data still lends itself to uncertainties in forecasting strong Pacific storms."

https://weather.com/science/weather-explainers/news/toughest-weather-forecast-places-us

More........

"There are several places where it is difficult to predict weather:

1) Places where there are not ground stations and places where weather balloons are not launched. Examples include the ocean, the Arctic, and countries that do not have a network of weather stations or a system for launching weather balloons (done at National Weather Service offices in the US). Knowing what the current weather conditions are is one of the key pieces of information that gets input into weather forecast models. While we do have global satellite coverage of the Earth that helps a great deal, it is still not as good as data from near the ground.

Along a similar argument, places where the upstream weather does not have data from ground stations or weather balloons can be a little bit more difficult to forecast. For example, it is more difficult to forecast the weather in Seattle (and along the west coast of the US) than in New York (and the east coast). This is because in the US, weather systems typically move from west to east. So when making a forecast for New York, the weather forecast models have the benefit of the dense network of weather stations to west. Conversely, there is ocean to the west of Seattle, where there are not weather stations."

https://www.quora.com/Where-globall...ave-the-most-difficulty-predicting-conditions

 

[Hippocampus]

Very interesting articles PS. From experience wonder about the edges of the Gulf Stream as well. Think due to breakouts, curls and convergence of several weather elements (such as near Bermuda) the regional forecasts you get off of examination of the 500mb, charts, gribs or text forecasts is fairly often inaccurate in predicting hyper local weather. My impression is this is particularly true on the northern side from mid Atlantic states up to R.I. and north of PR to Abacos as well. Sure you download the stream so have a good sense of where it is and what it’s doing but you’re sitting in a fresh breeze with the arrows showing half a vane. Similarly have learned to be very conservative in trusting things around Hatteras/ cape fear. Fortunately the ICW for Norfolk-oriental is a easy stretch.

 

[Porgy]

Hippocampus mentions Florida to the Chesapeake, 750+ nm from Miami. I read of and met plenty who routinely do that trip or from Miami/Bahamas direct to Rhode Island 1000+ nm. I’m sure no big deal for him but, that puts you 200-250 miles from land at it’s furthest. That sure seems out there to me, where you aren’t going to run to shelter in a few hours or dodge your way around storms. While I’m sure there may be those who do those trips in SD boats, all those I’m aware of have been offshore cruising sailboats or FD trawlers.

While SD boats give many the flexibility they want for their travels, it seems that for how Hippocampus intends to use his, a FD offers the greatest flexibility. He can take his time and run inside if he wants or he go directly from Newport to the Abacos - and back again without refueling.

 

[psneeld]

SD boats have crossed oceans, lots of SD boats travel to well off 100 miles to/from East Coast ports, even just a days fishing.


Storms don't necessarily sink SD boats any more than FD boats...lot's more than just FD/SD determines seaworthiness...like owners who choose FD boats, etc...


I would say bar crossing can be just as dangerous as many storm waves, if not way more so...the duration is shorter but the few waves that are important can be killers. SD boats cross the bar regularly too.

 

[rslifkin]

Thanks for the benefit of your insights. So far this thread has been very helpful. Do notice on the SDs we’ve toured although lockers are more commonly latched floorboards and constraints on shelving not so much. We’ve had latches even on compartments with vertical access under the settees cushions installed. Before passage would stuff pillows or bedding into any residual space in lockers so there was no possibility of things shifting. Thinking was you don’t need a knockdown for things to get moving or even flying. Do you have similar concerns? Have you made modifications to prevent this? Do you routinely prevent chairs or other seating from shifting by a modification before leaving?
When storing things always tried to put the heavy stuff close to the center and low. For a given LOA power tends to be much heavier than sail. Especially for FD boats. Outbound46=30k lbs. N40=50k lbs. Do you have a similar concern about gyradius and heavy ends with your boat or is the impact so minimal as not worth worrying about?

Weight varies dramatically with boat design. My 38 footer is spec-ed at 21,600 lbs dry, so I figure 26k loaded, maybe a little more. A GB36 is 26k dry, the 42 is almost 35k dry. The FD stuff like a Nordhavn tends to be far heavier, as the weight has far less of a performance impact. So they build it how they want and as strong as they want, but don't worry nearly as much about making anything lighter. At the extreme opposite of the Nordhavn, a dock neighbor has a Sea Ray almost identical in dimensions to my boat, but not as tall (being an express cruiser). It's a whopping 5000 lbs lighter than my boat. Even the sport fish they built on that hull is still 3000 lbs lighter than my boat.

I don't worry about latching floor hatches. At least on my boat, if I get knocked far enough for a hatch to depart its intended location, I'm at least into the range of downflooding through the engine vents and possibly into the range of "it's not coming back".

I do give thought to where things are placed, or modifying storage locations a bit to make sure things don't go flying. Outside of passagemakers, manufacturers know that 95% of the boats they sell won't be used anywhere near their maximum capability. So they save some cost by not optimizing storage for rough seas.

Furniture-wise, I have a pair of bar stools that get laid down in rough seas, as they'll fall over somewhere around a 20 - 25 degree roll depending on how violent the roll is. The previously mentioned very steep 4 - 5 footers against a river current (which produced enough pitching that I was expecting to put the pulpit into a wave) didn't tip the stools. The club chair and hi-lo table have never moved that I've seen, so I don't know what it would take. The table would probably slide first, but the chair is a bit heavy and the feet sink into the carpet, so I'd expect I'd be in the 40 degree range before it goes anywhere. If I ever expected to see conditions where those would be an issue, I'd find a way to secure them. But those conditions would be really pushing the limits of my boat, so I avoid them by a pretty good margin.

 

[mvweebles]

Interesting read on weather forecasting difficulty around the nation......

It does mention what I've heard....below is from a couple articles.

"Forecasting in California is challenging?

https://www.quora.com/Where-globall...ave-the-most-difficulty-predicting-conditions

Forecasting for land locations may be difficult, but I found the forecast products for ocean forecasts pretty reliable - but from a synoptic point of view, not an interpolated "Buoyweather" nano-forecast point of view. The weather all comes down from the NW where there are a lot of weather stations.

That said, I think where cruisers do themselves a disservice is by not learning a bit more about weather forecasting. I know there are some great packaged weather products on the market (I use PredictWind via IridiumGO), but there is no substitute for learning the synoptic view of weather.

Attached are two sets of charts - surface and wind/wave for 48-hr forecast (valid for tomorrow evening local time), and for 96-hr forecast (2-days later). If you wanted to move a boat southbound from SF, there's a possible weather window opening in the +96-hours timeframe. Not sure its enough of a window to head northbound from SoCal to SF, but as the cold front moves north and the low pressure moves inland, the pressure gradient will reduce. Boats such as ours are not moving until that happens. Forecasting is reasonably accurate in the 48-hour time frame, and the 96-hour forecast gives directional indicators for 72-hours (there are also 72-hour forecasts for surface and wind/wave).

There are a couple absolutes: First, these forecasts will not be 100% accurate. But on the inverse, they will not be 100% wrong which is what would need to happen to be ultra-surprised and suddenly find yourself in unexpected survival conditions. Weather is driven by movement of pressure systems - these do not move in schizophrenic ways. Now, local environmental conditions will have highly localized effects - bar entrances, headlands, etc.

Good discussion

Peter

 

[psneeld]

If you think there are a lot of weather stations between Japan and the West Coast (compared to 3000 miles of populated USA)...well OK...I am just sticking to what a couple of professional weather forecasters published and what I learned through decades of dealing with pro forecasters.


I had the pleasure of flying routinely in the bearing Sea, North Pacific, South Pacific near Antarctica, South Atlantic between Antarctica to the S.Orkney Islands, Antarctica, Gulf Coast, East Coast, All around the East side of Greenland to near the North Pole. The difference in weather forecasting was dramatic. Granted this was before better satellites...but as my links suggested, satellites aren't the full story. I was usually the aviation detachment crewmember responsible for working with the ships weather petty officer to sent data to the Navy Weather Forecasters who at best sent us back yesterdays weather.... Hope it's better now...



Yes...learning a bit about weather behooves any cruiser.

 

[mvweebles]

Thanks for the benefit of your insights. So far this thread has been very helpful. Do notice on the SDs we’ve toured although lockers are more commonly latched floorboards and constraints on shelving not so much. We’ve had latches even on compartments with vertical access under the settees cushions installed. Before passage would stuff pillows or bedding into any residual space in lockers so there was no possibility of things shifting. Thinking was you don’t need a knockdown for things to get moving or even flying. Do you have similar concerns? Have you made modifications to prevent this? Do you routinely prevent chairs or other seating from shifting by a modification before leaving?
When storing things always tried to put the heavy stuff close to the center and low. For a given LOA power tends to be much heavier than sail. Especially for FD boats. Outbound46=30k lbs. N40=50k lbs. Do you have a similar concern about gyradius and heavy ends with your boat or is the impact so minimal as not worth worrying about?

I agree that SD boats tend to be more formatted for level operation than a FD. But I actually think this says more about the owner than the boat. There was a recent thread on furniture - built-in vs household. There were many proponents of unsecured or lightly secured household furniture. Most boats (FD and SD) have nice lamps, candles, coffee table books, all manner of potential projectiles. Even FD boats have succumbed to the marketing draw of household refrigerators that are happy to eject a carton of eggs without much provocation. Simply having sheets of padding to put between plates makes a lot of difference - keeping the galley quiet during boisterous weather goes a long ways to keeping the fear-factor down, especially at night.

But my biggest pet peeve about many boats are non-watertight windows. Being in sustained heavy spray conditions will find the leaks. FD boats tend to be higher quality construction with better ports vs windows.

In the end Hippo, I think your observations say more about the owner than whether the boat is FD or SD. FD owners simply have a different philosophy which is driven by the intended usage whether fulfilled or aspirational.

Peter

 

[bayview]

Regarding big waves, a few weeks ago at Mavericks, NoCal. The Vid is worth watching whether you surf or not.

That PIX is from a well known surf area.
( Mavricks). The storm that caused it was probably very well forecasted. A short distance away is the entrance to Half Moon Bay harbor that has different conditions.

 

[mvweebles]

If you think there are a lot of weather stations between Japan and the West Coast (compared to 3000 miles of populated USA)...well OK...I am just sticking to what a couple of professional weather forecasters published and what I learned through decades of dealing with pro forecasters.

Yes...learning a bit about weather behooves any cruiser.

There are indeed quite a few weather stations - here is a listing of the buoys mid-ocean.

https://www.ndbc.noaa.gov/

There are also forecast tools using satellite, radar, and upper air. I don't think the Pacific is a black hole for forecasting.

Peter

 

[psneeld]

OK...I guess the 2 experts I linked just don't see it your way...or other weather guys I have discussed weather with.


How many buoys? Like many buoy reports how many have certain systems knocked out for months and months?


Here ya go as a comparison....


https://www.wunderground.com/about/data



"Current Conditions. U.S. current conditions data comes from 180,000+ weather stations across the country including: Almost 2,000 Automated Surface Observation System (ASOS) stations located at airports throughout the country."

 

[mvweebles]

OK...I guess the 2 experts I linked just don't see it your way...or other weather guys I have discussed weather with.

It's not 'my way.' Its how the raw data is presented. The links I read - including Wunderground - are more concerned with land-based forecasts so a different animal from marine forecasts. Given the influence of varying geographical influences on land, I can certainly understand how micro-climates variations can slip between zones in forecasting.

The attached picture shows the Natl Data Buoy Center's buoys in the northern Pacific region, the coverage area of the surface/synoptic charts I sent from the NWS (both NWS and NDBC are part of NOAA). The legend on this URL states of the 1429 buoys, 937 have reported in the last 8-hours (yellow buoys), or 65%.

Places like Wunderground, PredictWind, Windy, BuoyWeather, etc. all use this same raw data, they just have proprietary algorithms that interpolate the data to give point-forecasts. Personally, I find the NWS forecasters - the folks who sign the synoptic charts - the most useful as they provide some human intervention and overlay to the data.

All I can say is I found the marine weather forecasts along the Pacific Coast to be reliable and dependable within the confines of weather forecasting. I would never imply I didn't hit unforecast conditions, but I was not hugely surprised either.

Peter

 

[Hippocampus]

Totally agree Peter about learning weather. Thought I knew something until I did a Lee Cesneau course. Just being able to read a weather chart, the 500mb and your own local onboard instruments including a recording barometer has allowed me to understand the limitations of the Grib charts. Personally I’m a big fan of passage weather. All the paid services are taking information in the public domain and repackaging it then charging you for what you already paid for with your taxes. Passage Weather is at least honest about this and only asks for a voluntary donation which I’m pleased to do. Also I find the simple arrows much easier to read and prefer their low baud data when that’s needed. Having simple access to the barometric chart to compare to the gribs leads to reassurance. Don’t know why anyone would pay a fixed rate for any of the services you mentioned above.
Find understanding waves and local effects allows one to predict local phenomena. Things like compression zones as you travel between islands or downdrafts with mountains. Sure it’s simple physics but I didn’t think that way until being taught. So even if you’re just messing around with boats locally think it’s time well spent to learn about weather. Also it’s fun and another arrow in the quiver.
Still, know what I don’t know so for long hops or passage think it’s short bucks and worth it to use a weather router. Some like Commanders. Personally been real happy with Chris Parker. $300/yr. and have all I want with a personal touch.

 

[mvweebles]

I used a weather router a couple times on long runs and under-equipped [new] boats. I didn't care for it as I felt blindfolded. Maybe if I'd had the same weather charts he did and we could discuss it would be better, but relying on external source was not great. But that was a long time ago,

So Hippo - what are your conclusions/inclinations to your own questions from the OP? You ask about vessel design - I can't really think of a lot of design items, but I can think of many construction details (e.g. watertight windows and ports). Given all your search, and your conversations, and all your experience, how would you answer your questions?

So here’s the question. Are active techniques different for SD v FD in weather? If so how? Specifically what techniques do you use? At what point and how do you employ passive techniques such as sea anchors and drogues? What are your feelings about vessel design for vessels doing multi day near shore (<50nm) transits? ​

 

[AusCan]

When securing the load for rough seas, it's worth looking at more than just the portable furniture (which I would never consider). During one of my first ventures out in ugly weather my hot water tank broke loose from its mounting points causing me some grief. The movement kinked the engine coolant hose causing high engine temperature. I've also had the fridge come loose from its mounts.

Since then, I've gone through the boat to ensure that all equipment is suitably secured so it will survive a pounding. Special attention to batteries and toolboxes. I ensure there is nothing in the engine area or in a compartment with a seacock that can move.
I don't have lockable hatches, but I'm good for 70 degrees.

 

[rslifkin]

Those are good points. There's a big difference between "mounted" and "mounted securely". And it's not always all that obvious.



Good to know on the hatches holding to 70 degrees without latches. If I ever get that far over, I doubt it's coming back.

 

[AusCan]

I agree that SD boats tend to be more formatted for level operation than a FD. But I actually think this says more about the owner than the boat. There was a recent thread on furniture - built-in vs household. There were many proponents of unsecured or lightly secured household furniture. Most boats (FD and SD) have nice lamps, candles, coffee table books, all manner of potential projectiles. Even FD boats have succumbed to the marketing draw of household refrigerators that are happy to eject a carton of eggs without much provocation. Simply having sheets of padding to put between plates makes a lot of difference - keeping the galley quiet during boisterous weather goes a long ways to keeping the fear-factor down, especially at night.

But my biggest pet peeve about many boats are non-watertight windows. Being in sustained heavy spray conditions will find the leaks. FD boats tend to be higher quality construction with better ports vs windows.

In the end Hippo, I think your observations say more about the owner than whether the boat is FD or SD. FD owners simply have a different philosophy which is driven by the intended usage whether fulfilled or aspirational.

Peter

I agree Peter, the sliding windows in most trawlers leak like a sieve. When hit with breaking waves, a substantial amount of water is jetted through my sliding saloon windows at the drain points at the bottom. They held up though; I'm glad the deckhouse walls are solid fibreglass.