Are there any "full displacement hull" trawlers out there?

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kurt.reynolds

Senior Member
Joined
Apr 20, 2013
Messages
134
Location
USA
Vessel Name
Grace
Vessel Make
1982 Grand Banks Motoryacht
I am in the market for a trawler style cruiser. I love the grand banks 42 and have a 100k budget give or take, so have a lot of options.

I was reading an article today about the down falls (fuel efficiency) of twin engine semi-displacement boats. I have found that I cannot find a single engine Grand Banks in my budget, because I guess there are not a lot out there.

Of course, the internet can not decide what boat is best for me, but what "full displacement hull" boats are out there in the coastal cruiser and/or ICW cruiser category? I cruise mostly in Southern Chesapeake Bay and Coastal Carolina's.

Thanks,
Kurt
 
I would not to get too hung up on whether it is FD or SD. You are severely limiting your search by demanding that criteria. A FD hull might save you 5-10% in fuel burn. Fuel is a very small fraction of total cost of a boat. With that said, There should be quite a few GB36s that were single engine???...if you are hung up on that Brand. Also, if you go as small as a 32 those are singles as well. Other than that, if you are looking for help with the type of boat you are looking for, more information is needed from you. Also, check out the "Boat Search 101" sticky thread on here....
 
The only reason for twin engines is maneuverability, and some say redundancy. Too much maintenance for my way of thinking. If you want to move a given hull through the water at a certain speed, it will take a fixed amount of horsepower to accomplish that. One engine or two, same thing, same amount of power. If you want to go faster than hull speed in a semi-displacement hull, just start pouring on the horsepower (and the fuel), the amount you have available is the maximum speed you will achieve.

Grand Banks began putting large twins in its latest boats and I believe you could get a GB42 to do about 25 knots but the fuel burn made the Saudis grin and it threw a wake like a destroyer. Lots of horsepower, big fuel burn.

The earlier GBs could have been had with a single 120 hp Lehman that could make hull speed with no problem. In fact, the 42 that I really wanted badly had a single Gardner in her, probably the boatiest motor ever floated with endless brass and copper fittings that had to be polished lest you be drummed out of the GB club.

I would prefer a single GB, with or without a bow thruster, for economy and lower maintenance. No problem doing trawler speeds.
 
The're not very many out there. Most trawler owners feel the need to outrun weather and have extra power.

They do however come in more variations than you probably realize. For example there are many w hard chines and often in light displacement versions. You mention Chesapeke Bay that I think is rather shallow so anchorages likely will be shallow too. Look on YW and when you see something that attracts you pop it up here and comments will give you an almost immediate idea if it is FD and or something you want. I don't know if it's seaworthyness or fuel burn advantages you're after but keep in mind that on an average SD trawlers require 1.25 to 2 times as much power to drive. And you also should be aware that FD craft do not travel at hull speed ... but about one knot below hull speed. Traveling at hull speed is the domain of SD hulls.
 
There is a significant difference in fuel consumption, as much as 50% difference, between a true full displacement hull and a semi displacement hull while going less than hull speed.

But this is maybe 2 gph vs 3 gph to push a 30,000 lb boat to 7 kts. $2.50 per hour!!! Unless you put hundreds, maybe thousands of hours each year on your boat, it will be relatively insignificant in the grand scheme of costs of owning and operating a boat.

David
 
Stay one knot below hull speed and you'll obtain fuel efficiency with one engine or two.
 
you might check out Kadey Krogen if you like the full displacement idea
 
Kurt,
Go find some on YW and post them here.

Something not often mentioned here FD/SD wise re drag is displacement. Years ago I heard or read someone using displacement to calculate power requirements for FD boats. I adopted it and over the years of comparing many numbers and hulls gave me a good comparative scope on the question of drag and power requirements. Four hp per ton of displacement seemed to be enough power and anything less seemed clearly not enough. My boat has 5 and is more than enough.

So as you compare FD boats and consider that if boat X weighed half as much as boat Y they could likely have the same drag and the same fuel burn. So a SD boat weighing considerably less than a FD will have "considerably" less drag and hence fuel burn. Most SD boats will weigh less than FD boats and will have less drag because of it so a SD boat halving almost as low drag as a FD will most likely be far lighter than the FD counterpart. So a SD boat can have even comparable drag as a FD boat if it weighs about half as much. Most SD boats weigh more than that. So if a SD boat has similar fuel burn it will be because of the much lighter weight not the hull shape. Pound for pound a 15 ton 34' SD boat will have almost double the drag of the SD counterpart. By pound for pound I mean both 34' boats will weigh the same.

So how close or distant a SD boat's drag is compared to a FD boat depends on how light it is and that will depend on what operational speed the designer intended for the SD boat. Usually the faster the speed designed into the boat the more weight will be designed out.
 
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Eric, isn`t the FD boat likely to be "rolly". My friends FD Resort 35/Cuddles rolls a lot more than my SD when we are in company.
 
Eric, isn`t the FD boat likely to be "rolly". My friends FD Resort 35/Cuddles rolls a lot more than my SD when we are in company.
Yes - FD boats are in general more inclined to roll given their hull design. That's why you often see them with steadying sails, paravanes, fin stabilizers, flopper stoppers, etc.

Richard
 
Kadey Krogen, Nordhavn, Willards, some DeFevers.

Full Displacement's advantage is in its offshore seakeeping ability. The trawlers that make it down here to the Eastern Caribbean, or which cross an ocean are almost always among that small percentage of trawlers which are full displacement.

As with anything on a boat it is important to determine how you are going to use it. Figure out where you are going to use the boat and then work backwards as to the type of boat that works best for that use.
 
I second the concept that if it takes 30-40HP to cruise the advantages of a single screw displacement boat become minor.

The hassle with twin engines on a small boat is servicing them , not fuel consumption.
 
Maybe I'm defending my own choice, but I like my FD hull for holding 600 gallons of fuel and 300 gallons of water. A single diesel garners me a roomier ER and greater range (2knm) than twins, even after I give up a little space for the electric get-home (which I've never had to use, but it's nice to know it's there). I know a boat of equivalent displacement will have equal volume below the waterline, but naval architects often use those square corners for living space instead of fuel.

It is true, though, that I spent a lot of time on the minutiae of fuel burn before accepting that fuel is just one of many boating expenses, as others have also said.

Andrew
Willard 40 Hull #1
 
The square corners and flat bottom aft is what ruins seaworthyness w SD trawlers. Not to mention the small rudders.

My W30 is on B float.
 
The square corners and flat bottom aft is what ruins seaworthyness w SD trawlers. Not to mention the small rudders.

My W30 is on B float.

It is also what ruins fuel efficiency!
 
I can't comment on US makes but from my own practical experience.
Both FD and SD are great load carriers.
I've found an SD working at displacement speeds to be the best compromise in getting the rated hull speed and economy.
Recently I cruised from Ireland to the Mediterranean with my own 42' Perkins 80 hp SD single engine cruiser in company with a 32' SD with 2 x 120 Volvo's.
Having cruised for a couple of days at hull speed there was only cents when we refuelled BUT the moment he opened the throttles full he got 5 knots speed increase but his fuel burn was 40% more.
I can walk around my ER for servicing, he has so little space he can barely change filters when servicing.
His 32' boat only has a flybridge command and tends to roll a fair bit, my own has both and I use the lower helm at sea with far less roll.
As FF and others pointed out the servicing/noise/accessibility/costs are much greater for twin installations and considering the reliability of a well maintained diesel I would never dream of owning a twin.
A bow thruster 1 size above the recommended size takes care of any manoeuvrability issues.
 
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Henry's boat above is a good example of a hard chine beamy boat that probably dos'nt roll much. May be their best selling feature for many.
 
Kurt,
You're a good looker.
If you can afford a Willard 40 I don't see how you could go wrong. This one has an old engine but I know of no chronic problems w the Perkins. Everything I've heard has been positive but I'm no expert on the brand. Read some of the other posting on the 6cyl Perkins.

Read about the W40 in the great book "Voyaging under Power" by Bebe. This boat is considered a passagemaker. Some passagemakers don't make good coastal cruisers as they have design variations that lean toward long ocean travel ... very different.

So if you get by the old engine and possible design unsuitabilities the survey is the only bridge to cross. This price seems very reasonable. Basically if this is the kind of boat you want it will be hard to beat.

Not being very familiar w the 40 my comments are only a light introduction.

Opps ...
I was confusing this with another boat here in the west but I've edited and all else is valid.
 
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I am in the market for a trawler style cruiser. I love the grand banks 42 and have a 100k budget give or take, so have a lot of options.

I was reading an article today about the down falls (fuel efficiency) of twin engine semi-displacement boats. I have found that I cannot find a single engine Grand Banks in my budget, because I guess there are not a lot out there.

Of course, the internet can not decide what boat is best for me, but what "full displacement hull" boats are out there in the coastal cruiser and/or ICW cruiser category? I cruise mostly in Southern Chesapeake Bay and Coastal Carolina's.

Thanks,
Kurt


Can I assume that your love of the GB 42 comes from many days of cruising on one and not just from walking the docks and listening to an owner tell you how much he/she also loves that boat?

Also your mention of an article on the "downfalls" of twin engine semi displacement boats, suggests that you are way too early in your search to eliminate the very boat you say that you love.

I have spend many a day on GBs, 36, 42, 46. None with singles though.
Good boats all. No "downfalls" that I could find that relate to whether they have singles or twins, None related to their being Semi Displacement.

Unless you are planning extended offshore cruising, where a FD hull will shine, you will find that a SD boat is perfectly suited to the ICW or any coastal cruising. Twins are as efficient as a single, as what drives up your fuel bill is not the number of propellers in the water, but the size of your stern wave. Keep that under control and the fuel cost is minimized.
 
Keith,
One "downfall" I suspect is excessive weight for twins. May only be a concern for the 36' boat.
On a GB I would limit my search to singles. And I actually would rather have a twin. Some GB's had a single JD. When I was shopping for a GB I found a JD boat and also a 36 w lightweight Yanmar twins.

Many or even most are'nt concerned about weight but for those that are holding out for a single may be worthwile. The GB has a wonderful hull IMO.

Keith wrote;
"Unless you are planning extended offshore cruising, where a FD hull will shine, you will find that a SD boat is perfectly suited to the ICW or any coastal cruising. Twins are as efficient as a single, as what drives up your fuel bill is not the number of propellers in the water, but the size of your stern wave. Keep that under control and the fuel cost is minimized."
I fully agree w this.
 
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Find a motorsailer, they have large engines (80hp and up). Take the "lighting rod" off and all the rigging and you have comfortable and efficient trawler. I have one.
 
"Find a motorsailer, they have large engines (80hp and up)."

The usual sail hull is very sweet and only requires about 3HP per ton (2240lbs) .

For many boats that hardly requires a "large" engine , especially if fuel burn and engine life are a consideration.
 
Starting contacting brokers yesterday, almost every boat I had on my short list is under contract or sold. Including the Willard and 4 GB 42's that were way up on my list. If you are looking to sell your boat, now might be a good time.

Thanks Everyone for contributing, I appreciate the help very much.
 

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