Definition Of Full Displacement

Just about every working trawler here would have a submerged transom.

https://www.boatsonline.com.au/boat...+Trawler+&action=search&match=all+words&pge=3

HaHa when we say “trawler” on TF I assume recreational trawler.

On TF very few FD boats have more than an inch or two below the WL. Of course there are numerous skippers here having SD boats that think they are FD. Many of those should be called “displacement” as they don’t raise their bow much if any so they sit completely “in” the water. But that’s defining them by speed more than hull design. One is limited with only FD, SD and planing. Too many boats are in the grey zones inbetween.
Does your boat look like menzies in post 97?

Nomad Willy said:

HaHa when we say “trawler” on TF I assume recreational trawler.

On TF very few FD boats have more than an inch or two below the WL. Of course there are numerous skippers here having SD boats that think they are FD. Many of those should be called “displacement” as they don’t raise their bow much if any so they sit completely “in” the water. But that’s defining them by speed more than hull design. One is limited with only FD, SD and planing. Too many boats are in the grey zones inbetween.
Does your boat look like menzies in post 97?

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No, my boat looks like the work boats that I linked to.
This was her in her previous life



And what her underwater shape at the stern is

Holy cow Simi. Looks like she’s haul’in net and at anchor. That’s strange.
The lower photo confirms to me your boat is FD. Quite a bit of submerged transom but a lot of boat down deep. And I’m assuming your QBBL angle is fwd of the prop. That would limit your speed a bit I would think but prolly fly stuff.

300 T travel lift ... big. Biggest one ever lifted Willy was 100T but Willy’s not even 10% of that. You should post some more pics of your boat. Are they in the archives?

Nomad Willy said:

300 T travel lift ... big. Biggest one ever lifted Willy was 100T but Willy’s not even 10% of that. You should post some more pics of your boat. Are they in the archives?

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A couple put here just now


http://www.trawlerforum.com/forums/members/13645-albums809.html

300 tonner to get the 8 straps and spread the load.
Next one down has 4 straps so not as kind on the hull.
They do the 300t for the same price as the 4 strapper

Nomad Willy said:

Of course there are numerous skippers here having SD boats that think they are FD.

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Really, I didn't read that? I would have thought everyone knew what hull they were getting when they had the surveys done? I suspect that there are many on here that have no interest in a FD hull?

It's not that one is "better" than the other.

Simi 60 said:

A couple put here just now


http://www.trawlerforum.com/forums/members/13645-albums809.html

300 tonner to get the 8 straps and spread the load.
Next one down has 4 straps so not as kind on the hull.
They do the 300t for the same price as the 4 strapper

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Very nice conversion. A few questions.

What is the draft? The space aft of the PH, on the top level, was that turned into a master cabin (like the N62)? Or more a sky lounge?

No bow thruster? Have you considered adding one?

menzies said:

Really, I didn't read that? I would have thought everyone knew what hull they were getting when they had the surveys done? I suspect that there are many on here that have no interest in a FD hull?

It's not that one is "better" than the other.

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Most have no interest in a FD boat. Few trawlers are FD. And FD trawlers on the market command no price premium. FD trawlers are no more expensive than SD. And it is a matter of what is best. Most are SD so it can be assumed that SD is best.
However over time there have been many that have tried to get their boats blessed just as trawlers. After all this is the Trawler Forum so there is an amount of prestige associated with trawler ownership. Makes one part of the club. And if you expand the difference between a planing hull and a SD hull from a SD hull you arrive at a FD hull. So mental logic seems to dictate that a FD trawler is more of a trawler than a SD trawler. I think that is a mindset here. Too much evidence to that end. But then they (FD trawlers) don’t command higher prices. Go figure.

Nomad Willy said:

Most have no interest in a FD boat. Few trawlers are FD. And FD trawlers on the market command no price premium. FD trawlers are no more expensive than SD. And it is a matter of what is best. Most are SD so it can be assumed that SD is best.
However over time there have been many that have tried to get their boats blessed just as trawlers. After all this is the Trawler Forum so there is an amount of prestige associated with trawler ownership. Makes one part of the club. And if you expand the difference between a planing hull and a SD hull from a SD hull you arrive at a FD hull. So mental logic seems to dictate that a FD trawler is more of a trawler than a SD trawler. I think that is a mindset here. Too much evidence to that end. But then they (FD trawlers) don’t command higher prices. Go figure.

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I understand what you are saying, but I have always taken TF as a lifestyle forum, not boat design forum.

" And FD trawlers on the market command no price premium."

I would disagree, for a few.
The few, 1 in 100, that are built capable of making an ocean voyage are usually quite expensive due to far heavier scantlings and very different outfitting .MY estimate is 2x or 3x as expensive.


Wing engine , roll chocks or flopper stoppers ,,huge tankage , different heavier ground tackle and windlass all, are not cheap and hardly required for the lakes bays and rivers the usual "trawler" use.

Nomad Willy said:

Most have no interest in a FD boat. Few trawlers are FD. And FD trawlers on the market command no price premium. FD trawlers are no more expensive than SD. And it is a matter of what is best. Most are SD so it can be assumed that SD is best.
However over time there have been many that have tried to get their boats blessed just as trawlers. After all this is the Trawler Forum so there is an amount of prestige associated with trawler ownership. Makes one part of the club. And if you expand the difference between a planing hull and a SD hull from a SD hull you arrive at a FD hull. So mental logic seems to dictate that a FD trawler is more of a trawler than a SD trawler. I think that is a mindset here. Too much evidence to that end. But then they (FD trawlers) don’t command higher prices. Go figure.

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Eric - My good boating TF buddy:

The post above goes in circles. I'm getting dizzy!

In humor I say... upon your grave stone should be the acronym "FD". Upon mine - "P" For others - "SD" or "SP"... depending what side of the coin their personally descriptive preference lies

menzies said:

I understand what you are saying, but I have always taken TF as a lifestyle forum, not boat design forum.

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BINGO!!!

Winner, Winner... Chicken Dinner!!

FF said:

" And FD trawlers on the market command no price premium."

I would disagree, for a few.
The few, 1 in 100, that are built capable of making an ocean voyage are usually quite expensive due to far heavier scantlings and very different outfitting .MY estimate is 2x or 3x as expensive.


Wing engine , roll chocks or flopper stoppers ,,huge tankage , different heavier ground tackle and windlass all, are not cheap and hardly required for the lakes bays and rivers the usual "trawler" use.

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Much agreed!

This lifestyle thingis BS unless you like aboard.
It’s about the boat and cruises long and short.
This boating thing is just a hobby.
Something we do when we aren’t doing what other things one does or necessary things like food and shelter. “Lifestyle” ? You’re trying to make more of it than exists.

FF you’re right there are a few. I was addressing the common Trawler Former. I’d include myself but my boat’s too small.

Nomad Willy said:

This lifestyle thingis BS unless you like aboard.
It’s about the boat and cruises long and short.
This boating thing is just a hobby.
Something we do when we aren’t doing what other things one does or necessary things like food and shelter. “Lifestyle” ? You’re trying to make more of it than exists.

FF you’re right there are a few. I was addressing the common Trawler Former. I’d include myself but my boat’s too small.

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I disagree. If I spend a large part of my discretionary income and time on extended cruises, that is a lifestyle.

Plus, you clearly don't agree with the following:

The late Art DeFever, Naval Architect, is the man who rightfully earned credit for creating the cruising yacht designs we commonly call trawlers today. Since 1939, Mr. DeFever has drawn boats that are sea kindly, comfortable and pleasing to the eye.

Delfin said:

Be that as it may, I agree with NAs like Gerr that full displacement hulls are not designed to provide hydrodynamic lift.

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On this we agree.

Absent lift, you have a maximum hull speed where drag simply increases as you power the vessel faster. You disagree, which is fine, but I don't think the physics supports your position.

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On this, we don't agree, and almost every NA is on my side including Gerr. Without lift, the displacement does not decrease, and the drag curve is simply a classic wavemaking drag curve. These curves get steeper to the right, but never go vertical. That means more power = more speed. There is no maximum hull speed (well, the speed of light - but let's not go there). Here is a typical curve you can find in any book on naval architecture (including Gerr's). There is nothing at all remarkable about the 1.34 point on the curve - it is an arbitrarily picked point. To add power without a speed increase, the curve would need to be vertical, and it is not.

As a practical matter as you move to the right on the graph, adding power produces diminishing returns, and so there is a soft practical limit somewhere around S/L ratios of 1 to 1.5 depending on goals. No matter what the hull shape - sphere or Delphin - there are impractical ways to add nearly infinite power. The physics are well understood and on my side. What you say is a practical and economic limitation, not a physical limitation.

menzies said:

Very nice conversion. A few questions.

What is the draft? The space aft of the PH, on the top level, was that turned into a master cabin (like the N62)? Or more a sky lounge?

No bow thruster? Have you considered adding one?

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Thanks

6 1/2 ft draft + -

Aft of PH is a 2nd bathroom and master cabin with a walk around standard king size bed opening out onto a shaded deck area.

We only come into a dock maybe twice a year for fuel and water and choose a fuel dock with easy in and out.
Would probably look at stern thruster over bow but it is way down the priority list.

menzies said:

I disagree. If I spend a large part of my discretionary income and time on extended cruises, that is a lifestyle.

Plus, you clearly don't agree with the following:

The late Art DeFever, Naval Architect, is the man who rightfully earned credit for creating the cruising yacht designs we commonly call trawlers today. Since 1939, Mr. DeFever has drawn boats that are sea kindly, comfortable and pleasing to the eye.

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Art DeFever may have introduced the heavy cruiser but I see GB w the boat Spray then the 32 and 36’ trawlers in the early 60’s as the begining of the modern trawler. Then there are/were boats w/o the trawler style that led up to conventional trawlers such as the heavy cruisers ... Monk and the like. But I really don’t know what I’m talking about .. just mouthing what I think. I wasn’t interested in trawlers at all even in the 70’s. Who on earth wanted to go that slow. Interestingly I was born in 1939 and I don’t recall hearing bout DeFever until 07 on TF.

But re the lifestyle thing if it is it is.
So is flying and motorcycling.
If that’s all you do it’s a lifestyle.

Nomad Willy said:

But re the lifestyle thing if it is it is.
So is flying and motorcycling.
If that’s all you do it’s a lifestyle.

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Maybe we could expand [elasticize] the term lifestyle to include the word "partial"... as in "partial" lifestyle.

Thinking: Aren't we all living as personally designed life form [style] conglomerates of specific life-type [style] portions to which we each adhere? Motorcyclists have a "partial" portion of their life [style] ridding motor bikes. Boaters; "partial" portion [style] is on the water in crafts. Pilots' [style] is flying planes. Some persons practice doing all three [styles]. So, I guess, we could say each portion of what people often do is a "partial" lifestyle for them.

What started the "lifestyle" conversation was whether or not "trawlering" is being on a trawler, or living the trawler "lifestyle". Willy is suggesting that perhaps there is no such thing as a trawlering lifestyle.

Boats have been my life not a lifestyle, I worked offshore for years during the codfish boom in the eighties and then to Alaska in the early nineties. I loved a lot of boats, the old Ambassador you see as my avatar and several others. My first job as captain was on this one, the Nobska. I went on to own several and run others but it was never a lifestyle, it was always my life. Now that I'm aged a bit and have the medical issues that come with it life has slowed and I'm a dirt person until I get my boat done, then watch out. I should point out that for good or bad that's a trawler, everything without a net and fish blood is an imposter.

menzies said:

What started the "lifestyle" conversation was whether or not "trawlering" is being on a trawler, or living the trawler "lifestyle". Willy is suggesting that perhaps there is no such thing as a trawlering lifestyle.

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Details, details!! :lol:

Fish53 said:

Boats have been my life not a lifestyle, I worked offshore for years during the codfish boom in the eighties and then to Alaska in the early nineties. I loved a lot of boats, the old Ambassador you see as my avatar and several others. My first job as captain was on this one, the Nobska.View attachment 85028 I went on to own several and run others but it was never a lifestyle, it was always my life. Now that I'm aged a bit and have the medical issues that come with it life has slowed and I'm a dirt person until I get my boat done, then watch out. I should point out that for good or bad that's a trawler, everything without a net and fish blood is an imposter.

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Art, I should also point out that I didn't intend that as an insult, it's just the lament of an old trawlerman that's lost too many friends.

Fish53 said:

Art, I should also point out that I didn't intend that as an insult, it's just the lament of an old trawlerman that's lost too many friends.

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Not taken so by me. I never call any of my "pleasure boats" a trawler.

Greetings,
All I do is eat so I guess being fat is MY lifestyle...

I have a flat stomach, its just that the "L" is silent.

Is that FD or SD?

Like many changes with life and generatins in general... either you adapt or get left behind.


All the real boaters I know, they know the general description of a recreational trawler and use the term appropriately.


Fish guts and nets...yeah...sure....but for decades, recreational trawlers hanve been built, used and recognized by an industry and boaters that "get it".