Seaworthiness

[SoWhat]

Ted Brewer developed a "Comfort Factor" for sailboats as an indicator of motion comfort. The higher the number the smoother the motion and less likelihood of seasickness. The formula claims to assess is how quickly and abruptly a boat’s hull reacts to waves.

Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam↑1.33), where displacement is expressed in pounds, and length is expressed in feet.

A heavier boat will come out with a higher number as more weight dampens a boats motion. A lightweight beamy coastal cruiser would probably not be very comfortable in a heavy seaway.

I think "comfort factor" and seaworthiness are two different issues . I haven't seen any comparable formulas for trawlers but I suspect the typical hard chined flat stern section boat wouldn't score very high for comfort in heavy seaway.

 

[rsn48]

Here is a link to the David Pascoe article in three parts, I just finished printing them out:

https://www.docksidereports.com/rough_water_seamanship_1.htm

 

[ksanders]

Here is a link to the David Pascoe article in three parts, I just finished printing them out:

https://www.docksidereports.com/rough_water_seamanship_1.htm

These are Excellent reading!

 

[ksanders]

Here is seaworthiness...

We just had a member over at the Bayliner Owners Club complete the run bown the Baja peninsula in a Bayliner 4588 as part of the CUBAR rally.

 

[Simi 60]

A Grand Banks dory is seaworthy. Doesn't mean I want to cross the ocean in one.

Not when you can do it in a washing machine (-;

https://www.liverpoolecho.co.uk/news/liverpool-news/crazy-sailor-who-quit-teaching-13181462

 

[Art]

Seaworthy - Now h'e's 6'4, 210 and 1st year in Cal Poly, SLO.

There's a great story behind the look I was getting that day!! He did learn to row!!! LOL

 

[Art]

For those who really know how to take rough seas! - LOL

 

[JLD]

Ted Brewer developed a "Comfort Factor" for sailboats as an indicator of motion comfort. The higher the number the smoother the motion and less likelihood of seasickness. The formula claims to assess is how quickly and abruptly a boat’s hull reacts to waves.

Comfort ratio = D ÷ (.65 x (.7 LWL + .3 LOA) x Beam↑1.33), where displacement is expressed in pounds, and length is expressed in feet.

A heavier boat will come out with a higher number as more weight dampens a boats motion. A lightweight beamy coastal cruiser would probably not be very comfortable in a heavy seaway.

I think "comfort factor" and seaworthiness are two different issues . I haven't seen any comparable formulas for trawlers but I suspect the typical hard chined flat stern section boat wouldn't score very high for comfort in heavy seaway.

While I have do not doubt the logic behind the variables in the comfort factor formula, my understanding is that Brewer came up with the formula "tongue-in-check" on the back of a cocktail napkin.

There are lots of good discussion of 'comfort factor' on the various sailing forums. Interesting it almost always comes down to buying the best boat for your boating needs. One probably doesn't want a heavy boat for primarily light air sailing, or a very light boat for offshore sailing.

Jim

 

[SoWhat]

While I have do not doubt the logic behind the variables in the comfort factor formula, my understanding is that Brewer came up with the formula "tongue-in-check" on the back of a cocktail napkin.

There are lots of good discussion of 'comfort factor' on the various sailing forums. Interesting it almost always comes down to buying the best boat for your boating needs. One probably doesn't want a heavy boat for primarily light air sailing, or a very light boat for offshore sailing.

Jim

Yes, I think it was a joke. But anything on the internet automatically becomes law.

 

[BandB]

Words like "seaworthy", "bad conditions", "coastal cruiser", etc...etc are pretty meaningless unless parameters are discussed.

What is something to one person is something else to another.

If your boat can survive 7 foot seas, but the average crew gets so beat up to be fatigued to dangerous limits or flat out hurt...is that boat "seaworthy "?

Wifey B: YES, YES, YES.

What the heck is "seaworthy?" And to whom? Tell me about the captain and crew as they're more critical to the answer.

Please OP and others, don't ask questions that everyone here will interpret differently. Even asking "would you be comfortable cruising the East Coast with x boat?" gets you more interpretation than you can imagine. My Baby Riva is seaworthy. It's CE A. It can handle very rough conditions but don't intentionally go out in more than 4' or perhaps 5' and most of you wouldn't do that in it. And can't do much on seas with less than 200 nm range.

Yes, the Bluewater is "seaworthy," if you're talking coastal cruising. Would I cross the Atlantic in one? No way. Could it cross an ocean, yes.

 

[JLD]

Yes, I think it was a joke. But anything on the internet automatically becomes law.

I didn't mean to dismiss the formula, as I think it does have some value. Sailboatdata.com does publish the comfort ratio number along with all of the other specs they list.

Many of the sailboats I like, actually have a medium to higher comfort ratio. That is in part because I like a comfortable cruising boat over a racer!

Jim

 

[Slider70]

I commercial fished off the coast of British Columbia for 28 years. I owned three salmon trollers all built to fish and travel in adverse weather, if the skipper wished. I have owned a couple of larger pleasure boats, presently a 3870 Bayliner, built for PLEASURE if the name suggests their role in life?

I make it a point of never going out in adverse weather in a pleasure both unless I absolutely must. So far I have not had to and hope my pleasure boating continues that way.

On my commercial boats I had special plates install over the window as fellows I had fished with had either there glass blown out with a rough wave or the complete window with frame taken out. Just think about that for a minute. Think about how most pleasure boats are constructed. Now ask me about which pleasure boat is seaworthy?

 

[Nightflyer]

Unsinkable is a good quality

To some a 21’ Jon boat would not be a ocean going boat, but this one crossed over to Europe.

There’s a 11 part series on Prime Video titled “I Am Second Voyage”. Smallest powerboat crossing the Atlantic.

They set a world record. But also hold a record of going from the US to Bermuda and back.

An amazing trip but I’m glad I wasn’t on.

 

[Moonfish]

Enjoy your boat and when it’s really snotty stay in port and enjoy life.

I’d rather be sitting happy in port enjoying life than braving huge seas in any recreational boat.

Learn your and your boats comfortable limitations through practice and enjoy your boat.

Excellent advice!

 

[Moonfish]

I commercial fished off the coast of British Columbia for 28 years. I owned three salmon trollers all built to fish and travel in adverse weather, if the skipper wished. I have owned a couple of larger pleasure boats, presently a 3870 Bayliner, built for PLEASURE if the name suggests their role in life?

I make it a point of never going out in adverse weather in a pleasure both unless I absolutely must. So far I have not had to and hope my pleasure boating continues that way.

On my commercial boats I had special plates install over the window as fellows I had fished with had either there glass blown out with a rough wave or the complete window with frame taken out. Just think about that for a minute. Think about how most pleasure boats are constructed. Now ask me about which pleasure boat is seaworthy?

↑↑↑ This! ↑↑↑

 

[dirtdoc1]

The 40 Bluewater is a ballasted round bottom, displacement hulled trawler.

It is 12 inches narrower than a KK42 and has a finer bow section.

There were several BW40 built with coring, like the KK but the majority of them had solid FRP hulls.

The BW40 was designed as a single screw but most appeared to have been equipped with twins.

Does it have the "Wine Glass" shaped transom like the KK? If it tracks nicely in following seas it probably does. You might try the Rolling Chocks if beam seas are a problem. They work quite well if sized correctly.

Cheers!

 

[dirtdoc1]

↑↑↑ This! ↑↑↑

Darren,

That sounds absolutely terrifying!

 

[localboy]

I make it a point of never going out in adverse weather in a pleasure both unless I absolutely must. So far I have not had to and hope my pleasure boating continues that way.

Us too. Our boat is small by all your standards and while I trust it's "sea-worthiness", pushing the envelope is not smart nor fun.


A few yrs ago we were safe at a marina in Ganges Harbor, BC. I listened to the weather and it was going to blow; small craft advisory with winds up to 30 knots and seas up to 5-6'. Hell NO. Told The Admiral, we are staying put for one more day. The older couple next to us starts untying lines on their 26' Bayliner. I ask where they are headed and if he checked conditions. Yep, he did...says they are headed S/W to go home. The timing was not good IMO.



That afternoon/night it blew and rained like hell. We walked up to Moby's (sports bar/restaurant) and watched MNF on the big screen (after the hockey game, of course). That was the night the Seahawks played MNF and the power in Seattle went off...due to the same storm.


Sure hope those folks and their dogs were OK.

 

[syjos]

Does it have the "Wine Glass" shaped transom like the KK? If it tracks nicely in following seas it probably does. You might try the Rolling Chocks if beam seas are a problem. They work quite well if sized correctly.

Cheers!

It sorta does. The KK42 has less transom in the water than the Bluewater.

But Sandpiper handles big waves the best in following seas. The AP keeps course downwind.

 

[Nomad Willy]

syjos,
Looks like a good lobsterboat (built down).

 

[Fish53]

The seaworthiness of a boat is determined by the person operating it, an idiot in a good boat still isn't seaworthy.

 

[Nomad Willy]

Fish,
One of the elements indeed.

 

[Art]

The seaworthiness of a boat is determined by the person operating it, an idiot in a good boat still isn't seaworthy.

Well put.

However, I must add... on the other side of the coin... Best captain ever in a crap boat can be unseaworthy too.


sea·wor·thy /ˈsēˌwərT͟Hē/

adjective: seaworthy; sea-worthy

(of a vessel) in a good enough condition to sail on the sea

 

[OldDan1943]

and common sense

 

[Art]

sense /sens/

noun: sense; plural: senses

a faculty by which the body perceives an external stimulus; one of the faculties of sight, smell, hearing, taste, and touch.


Therefrom which I believe emanates - "Common Sense"; with the necessity of brain power to be included for "reading" the senses [ie. the "scenes" - at hand]. This includes the brains of humans, dogs, bears, fish, insects... etc, etc. We are not the only entity with brains, and, our physical senses in general may actually be substantially less acute in comparison to other living entities' senses.

That brings in the ultimately important factor of "reasoning"! Ahhh - now that my friends is what sets us humans atop of all other living entities on Earth. We can reason!

Let us hope that civilization soon enough reasons [thinks] itself ways to divert oncoming climate/environment/ecosystem collapse. We can be successful... but only by soon enough applying enough "reasoning".

 

[DNT99611]

syjos,
Looks like a good lobsterboat (built down).

I have seen the term "built down" mostly with lobster boats for years.
What does the term mean?

 

[syjos]

Built down lobsterboats have a skeg/keel that is an integral part of the hull, curving in from the sides. Skeg built has the skeg/keel attached to the bottom of the hull with a hard angle.

The built down has more carrying capacity and the skeg type is faster.

 

[Fish53]

Well put.

However, I must add... on the other side of the coin... Best captain ever in a crap boat can be unseaworthy too.


sea·wor·thy /ˈsēˌwərT͟Hē/

adjective: seaworthy; sea-worthy

(of a vessel) in a good enough condition to sail on the sea

That's just the point, a good captain doesn't sail on an unseaworthy vessel. Being seaworthy starts at the dock.

 

[Fish53]

Built down lobsterboats have a skeg/keel that is an integral part of the hull, curving in from the sides. Skeg built has the skeg/keel attached to the bottom of the hull with a hard angle.

The built down has more carrying capacity and the skeg type is faster.

By definition a built down boat has a garboard strake, a skeg boat does not. The assumption that a skeg boat is faster than a built down boat can get you into some mighty hot arguments around my part of the country. The theory is the abrupt angle where skeg meets hull creates turbulence where having a garboard provides smoother water flow. You see both types in evidence at our lobsterboat races. (I live in Maine despite my claim of Pitcairn Is.)

 

[syjos]

That's just the point, a good captain doesn't sail on an unseaworthy vessel. Being seaworthy starts at the dock.

I agree 100%

I have declined delivering boats when the boat is not seaworthy.