Great Harbour N37 Young America at our dock yesterday

The GH and N share the same hull design, which is similar in proportions to boats done by both Phil Bolger and Jay Benford. The shape draws from twin screw workboats generally, but not one in particular. Despite the apparent crudeness, its a fairly sophisticated hull shape with reasonably fine waterlines forward; buttocks aft that minimize the stern wave, almost eliminate squat at hull speed, and allow for a large diameter propeller; and chines and skegs that incorporate a massive amount of roll damping. All ideas taken from workboats.

It is a true displacement hull designed to run efficiently at very close to hull speed, but it will not go faster. The 37 uses about 40 horsepower at 7 1/4 knots, fully loaded. The 47 uses about 60 if I recall correctly, at closer to 8 knots.

The original plan was that the boat would be built using FRP panel one off construction, so all the shapes had to be developable with fairly gentle curves. Like a lot of projects, plans changed along the way and a hull mold was made, but we decided to stick with the shape to make tooling affordable.

Also in the original plan was the ability to lengthen the 37 hull. The hull was designed and the mold was built with a shape that allowed for a prismatic insert, a section where all of the buttock lines go fore and aft, parallel to the waterline, across the hull. Everything lines up and fairs in, except for the sheer line in profile.

Lou

Hi Lou,

Welcome aboard

Someone at work accused me of not being 'normal' the other day...my reply was that if being normal meant living in the middle of the herd and never taking risks, no thanks! (Thought you might get a kick out of that).

Thanks for weighing in Lou. Hope you're having a great Holiday. ERIC

Great to have you check in witb us, Lou. Best to you and yours for the Holidays.

LouCodega said:

The GH and N share the same hull design, which is similar in proportions to boats done by both Phil Bolger and Jay Benford. The shape draws from twin screw workboats generally, but not one in particular. Despite the apparent crudeness, its a fairly sophisticated hull shape with reasonably fine waterlines forward; buttocks aft that minimize the stern wave, almost eliminate squat at hull speed, and allow for a large diameter propeller; and chines and skegs that incorporate a massive amount of roll damping. All ideas taken from workboats.

It is a true displacement hull designed to run efficiently at very close to hull speed, but it will not go faster. The 37 uses about 40 horsepower at 7 1/4 knots, fully loaded. The 47 uses about 60 if I recall correctly, at closer to 8 knots.

The original plan was that the boat would be built using FRP panel one off construction, so all the shapes had to be developable with fairly gentle curves. Like a lot of projects, plans changed along the way and a hull mold was made, but we decided to stick with the shape to make tooling affordable.

Also in the original plan was the ability to lengthen the 37 hull. The hull was designed and the mold was built with a shape that allowed for a prismatic insert, a section where all of the buttock lines go fore and aft, parallel to the waterline, across the hull. Everything lines up and fairs in, except for the sheer line in profile.

Lou

Click to expand...

WOW Lou I just love it when to talk that way! Boat lovers like us really like hearing from a boats designer. Your collaboration with Ken Fickett resulted in a outstanding vessel. Owners quickly realize the stability and maneuverability of these trawlers! We have been amazed at how stable the boat is in a wide variety of water and weather conditions. All trawlers have pros and cons and for us the pros have far outweighed the cons!

I cannot resist putting some pictures to your words! Sorry that these photos are before, during and after, the bottom was blasted, sanded and painted but the lines are still visible.

Mr. Codega! The reason I found the Trawler Forum was when I
googled Great Harbour and you and Ken appeared in a thread here. So thank you. Also, to mention Phil Bolger and Jay Benford is meaningful. I knew you were good at the first sight of the N37.

Lou Thank you for joining in and giving us all what we crave. Tidbits of your wisdom and gift of designing boats. Have a wonderful and blessed 2015.
Jim

Hello all!! Does anyone know whether the N37 is EU Certified as Class A, Open Ocean?
Meaning: A. OCEAN: Designed for extended voyages where conditions may exceed wind force 8 (Beaufort scale) and significant wave heights of 4 m and above but excluding abnormal conditions, and vessels largely self-sufficient.
Thanks

No. But I'll let Lou or Ken address this question.

Wow,
Looks like the travel lift straps on the extremely hard Chines would be possibly troublesome.

Eric as I was reading an article about your maiden voyage of spoonbill to the islands the traveling reporter with you mentioned how the form stable hull and " sans stabilizers" performed as advertised in the moderate 2 to 5 foot seas on the nose and the occasional slammer.......Now then what are these sans stabilizers that are mentioned ? I thought you did not need to run stabilizers or ballast on these boats......am I missing something here ?
thank you
jim

Sans normally means "without" so I assume it means no stabilizers.....I am sure Eric will correct me

dimer2 said:

Sans normally means "without" so I assume it means no stabilizers.....I am sure Eric will correct me

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Dimmer,
Thank You and that sounds good to me !!

Interesting...

Site only lets me do one at a time...

Last one...

kraftee said:

No. But I'll let Lou or Ken address this question.

Click to expand...

Thanks

MurrayM - I am actually a very conservative designer. A builder is making a huge investment when they roll out a new boat and my first priority is to make sure that it performs as expected. Which is not to say that I always follow the crowd . . . .

Spotsville - Thanks for the pictures. They are an important addition.

Jobe - Mr. Codega is my father. I answer to Lou.

nickr - As far as I know, Ken has never gotten the boats certified for European export. Its an expensive proposition and is not required for US sales. I'm thinking that the N's could pass CAT A with some easily made modifications or substitutions.

manyboats - as the added photos show, the chines are not an issue on either the straps or the boat.

Thank you for the clarification. As I understand, a higher classed certification could help in acquiring better insurance rates. Might be expensive getting the boat evaluated/certified (needed anyway for export to EU) but you win in the long run insurance wise.

I looked long and hard at the massive swim platforms on the GH's, figuring that this style is what I would add to my own boat. The way we use our boat (or any boat) includes access to the water, and the GH design is the best overall production design I've seen for comfort in accessing the water. I've just completed the job, but I didn't add a skirt around the perimeter for extra strength, thinking that it may add drag in the areas pointed out in the photo below. Has anyone known this to be any issue?

It's just not an issue.

Larry

The swim platform on our GH47, even with a full fuel (1380 Gal) and water (480) and holding tank (320) does not drag in the water while underway or at the dock. I belleive that Lou's design forms a unique path through the water that produces very little squat while underway.

Also, the hull design leaves behind a wake that is kind to others (as we pass by)!

Spottsville said:

Also, the hull design leaves behind a wake that is kind to others (as we pass by)!

View attachment 35834

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And really frustrating for the PWC drivers trying to hop your wake!

Is it possible to install a Steadying sail system on the N37? Would it help in anyway based on its hull design?
People who have installed a steadying sail on their boat (regardless of make/model), either claim it has helped them out e.g roll damping and others who claim no noticeable difference at all.

Obviously, it's POSSIBLE to add a steadying sail - but I am not sure that it would have much effect on the GH hull with its very high initial stability. Again, probably a question best posed to Lou Codega or Ken Fickett.

kraftee said:

Obviously, it's POSSIBLE to add a steadying sail - but I am not sure that it would have much effect on the GH hull with its very high initial stability. Again, probably a question best posed to Lou Codega or Ken Fickett.

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I will pm Lou Codega and ask him. Once I get information on the subject, I will share it with you guys (for future reference).

To answer the question, we need to separate roll stability from roll damping. Often confused, they are totally different. Think in terms of the front end of your car - the springs provide stability and the shock absorbers provide damping. You need both functioning together to get the best possible ride down a rough road.

Stability is the tendency of a system to return to its original equilibrium when disturbed. This is GM, righting moment, stiffness in roll, and so on.

Damping is the ability of a system to dissipate the energy that it has absorbed back into the world. This is how quickly the boat stops rolling once it is disturbed.

Most people, in their quest for what they call roll stability, are actually looking for damping. Which is good, as there is not much that can be done to change stability after a boat is built other than massive ballasting. There are many ways to increase damping: gyro-stabilizers, bilge keels, paravanes, steadying sails, inherent hull shapes, and one or two others that I won't mention. Do active fins provide stability or damping? Ask the manufacturers. Not too long ago, they wouldn't sell you a unit unless your boat did over 12 knots.

Which finally gets us around to the question. The hard chines, wide beam and two large skegs give the N/GH hull massively inherent damping. I don't think that any reasonably sized steadying sail is going to make an improvement that is worth the price, in terms of cost, complication and reduced capability.

That said, Ken and I are both retired sail boat racers and we have talked about putting a simple, workboat style rig with a folding mast on an N for long downwind passages. It would save a bit of fuel and would be a pleasant thing to look at.

Lou

Thank you, for your input much appreciated.

Great Harbour Trawlers Build History

There has been a lot of interest on this forum recently in Great Harbour Trawlers and I thought I might provide, with some help from the Great Harbour Trawler Association (GHTA) archives, a little bit of build history. To date there has been a total of 55 of these stout little ships built, spanning 1996 to 2010. These 55 boats can be broken down into two size groups and four different models.

The original concept vessel was a 37’ model designated a GH37. Christened Hemisphere Dancer, she was completed in 1996 and was given hull #10 in the series. The first GH47, a ten foot longer version of the GH37, was built in 2000 and assigned hull #21.

In 2002, the first flush deck N37 was completed (hull #25) using the same hull mold as the GH37. This vessel was the first of three Great Harbour N37s to be christened Semper Fi and she was used as a demo boat for Mirage Manufacturing, the parent company of Great Harbor Trawlers. The last model to be introduced by Mirage was the N47, similar in layout to the N37 but built on the GH47 hull, which added ten more feet of waterline and was typically used for an extra stateroom and head. The first of the N47s was launched in 2007 (hull #46) and is considered by many to be their favorite Great Harbour Trawler model.

Of the 55 trawlers built, 54 of them are still plying the coastal and near shore island waterways as they were designed to do. The only hull loss has been a GH37, which was tragically destroyed in an arson fire that resulted in the death of the owner.

For those of you keeping score here is the build breakdown:

19 GH37 Models
21 N37 Models
9 GH47 Models
6 N47 Models

The last trawler built was hull #65, Island Swan, an N37 model in 2010. As some of you know, Mirage started construction late last year on a new N37 and when completed it will be hull #67 in the sequence. The reason for this as I recently discovered, is that hull #66 has been reassigned to Spoonbill (previously hull #64), an N47 model Mirage charter boat built just prior to Island Swan in 2009. Spoonbill was sold last spring and re-documented with the USCG as a 2014 model with the new HIN reflecting hull #66 and a March of 2014 certification or completion date.