Realistic top cruising speed for Nordic 42 ?

[Nomad Willy]

Hi-

My wife and I are contemplating purchase of a 2000 Nordic Tug 42 with a 635 HP Cummins QSM11 with 1500 hours.

I am looking to purchase a semi-displacment hull vessel that can cruise all day at 14 knots. Is this realistic? Or not with this setup....

This would be our first NT and diesel setup.

Thanks,

Mike

Mike,
The NT is a SD hull so your "top cruising speed" is just how fast the NT you want will go when the engine is at the max continuous output level. It may supprise you how high that output level is. And at the speed that max cont power delivers you may not like other things that may be going on. If it's choppy or worse you may not like the rough ride or all the seawater slaming down on the boat. Vibraation wise that speed may not be a "sweet spot". Or you don't like the bow high attitude. As in most things boating there are lots of variables.

But as to max continuous speed it's easy to find. You can probably just ask NT. By the way .. great choice of boat.

Oh I see Smitty in post #21 has it already researched.
A constant output of about 380hp should be a walk in the park for a 600hp engine.

 

[Nomad Willy]

Putting a boat of that size on the six small pads of that hydraulic trailer is a recipe for unseen structural damage to the hull skin!

I agree the aft pad is may be supporting over half the weight of the boat. And the fwd pad is probably just transfering weight to the aft pad. Bad

 

[RCook]

NT's are semi-displacement hulls. They will go quite a bit above hull speed, but at considerable cost in fuel. Don't know about the 42's max, but my 2002 NT37 with 330 hp Cummins hits 16 knots wide open. Friends say their 37 can go 12 knots all day, but I don't do that, more like 7-7.5 normal cruise, and max 9-10 (when I have a good reason to be in a hurry and am willing to burn much more fuel).

Numbers from this year's 5-month summer cruise of BC and SE Alaska:

Total nautical miles: 4403
Gallons burned (including generator): 1158
Overall average NM per gallon: 3.8

We traveled at 7-7.5 knots most of the time, but did 8 knots or more (relative to water, of course) maybe 10%.
On one tankfull, during which we kept more to 7, we calculated 4.4 nmpg.

 

[smitty477]

Mike,
The NT is a SD hull so your "top cruising speed" is just how fast the NT you want will go when the engine is at the max continuous output level. It may supprise you how high that output level is. And at the speed that max cont power delivers you may not like other things that may be going on. If it's choppy or worse you may not like the rough ride or all the seawater slaming down on the boat. Vibraation wise that speed may not be a "sweet spot". Or you don't like the bow high attitude. As in most things boating there are lots of variables.

But as to max continuous speed it's easy to find. You can probably just ask NT. By the way .. great choice of boat.

Oh I see Smitty in post #21 has it already researched.
A constant output of about 380hp should be a walk in the park for a 600hp engine.

FWIW - What I found on our last 47 foot 35000#+ boat was that the ride was most often much better at 17 knots then at 7 knots when in a choppy sea. The vibration and sound level was also very good when comparing the two speeds in rougher seas - you need to be able to achieve those speeds in order to do a fair comparison. The boat had twin 315 hp engines and would top out at about 22/23 knots.

 

[Rufus]

I agree the aft pad is may be supporting over half the weight of the boat. And the fwd pad is probably just transfering weight to the aft pad. Bad

Hydraulic trailers that do not lift via the keel should be banned.

 

[rwidman]

If you want to cruise at 14 knots all day you should be looking at a different kind of boat. Buying a slow boat for a fast journey is not smart.

That said, a Nordic Tug is a fine boat and 1500 hours is nothing on a diesel engine.

 

[eyschulman]

Another reinforcement that generalized statements that SD boats point their bows skyward at speed are not accurate. It depends on the hull design-drive train and weight distribution. I suspect some of this misinformed opinion is based in prejudice against the SD hull. I have been running high speed capable SD hulls on two different boats since 2007 and the ride is pretty flat on both. My present boat has trim tabs but they are not needed. I have observed SD boat ride nose up and Full displacement boats nose down it is all in the details of design implementation and how the individual owner might modify the equation. There is nothing inherently wrong with either type just different inherent capabilities with considerable overlap at and below hull speed. While a FD boat has a slight edge on fuel burn at lower speeds it is rarely an economically significant difference when comparing apples to apples. Depending on where and how the boat is used the ride roll and comfort differences can also cancel out. I would rather be anchored or slow running in a wake area with my present SD than my previous FD rolly Polly round bottom FD. I like both types and would own either depending on where and how I intended to use the boat.

 

[smitty477]

The way that boat is powered it can likely do 20+ knots on the top end - no problem cruising at 14-15 with that type of power.

 

[seasalt007]

I am on my second Nordic Tug 42, a 2000 model with a 330 Cummins and a 2006 with a 540 Cummins.

First, Nordic Tugs are not meant to plane but my newer one will easily. Keep your Exxon card handy if you choose to cruise much above 8,5 knots with either engine.

My 330 hp tug would top out at about 12 knots. We cruised it at 8.5 knots for almost 3,000 hours without a single problem. It went though three 1,000 hours checks which included a valve adjustment.

The 540 hp we have now will top out at about 19 knots with half fuel and water plus six passengers. It makes a very nice wake at that speed because it is fully up on top. The fuel burn at that speed is over 30 gph. At 8.5 knots the fuel burn is 7.7 gph. Anything in between it is plowing and will put out a wake that will roll a battleship over. Lugging with the bow high is not good.

I wish you well with that big engine. It should be fine for a long time if the PO treated it well.

A seasoned Cummins engine surveyor will be money well spent. He can ping all sorts of info about the engine's history.

 

[mvp]

I called NT

Ok..

So, I got the hull number and thought I might try calling NT to see if they had the original sea trials. To my utter amazement Dave pulled out the record and is sending me the original numbers..

Here are a few readings from 2000:

750 rpm...5 knots
2800 rpm.... 17 knots

The boat seemed "comfortable" at 2200 rpm when I was on it but I did not see the GPS speed....too busy looking at all the other gauges...


Dave will send me more numbers. I was hoping for fuel flow but for some reason they did not have or measure that. I thought the Cummins would have a smart craft gauge? Maybe not..

I think the original sea trial will be great to compare to a new sea trial.

M.

Attached is pdf report. Vessel Data speed slightly different than what is reported on second page under performance...

 

[rwidman]

.......... Keep your Exxon card handy if you choose to cruise much above 8,5 knots with either engine............. .

That goes with my comment about the choice of boats. The Nordic Tug will go fast but it and any similar boat will use a lot of fuel doing it. Going twice the speed doesn't use twice the fuel, it uses four times the fuel.

 

[seasalt007]

What am I missing? Looks like the engine is a 2300 WOT engine and the speed was 21.2 knots. That's what I would expect rather than17 at 2800.

I think page two is incorrect because page three shows that it is a 2300 rpm engine.

The 5.9 Bta is a 2800 rpm engine and my QSC 8.3 is a 2600 rpm engine.

I am more prone to believe page one that shows 21.2 kts at 2300...unless I am missing something

 

[mvp]

What am I missing? Looks like the engine is a 2300 WOT engine and the speed was 21.2 knots. That's what I would expect rather than17 at 2800.

I think page two is incorrect because the page three shows that it is a 2300 rpm engine.

The 5.9 Bta is a 2800 rpm engine and my QSC 8.3 is a 2600 rpm engine.

I am more prone to believe page one that shows 21.2 kts at 2300...unless I am missing something

Yes.. I see that as well and am calling someone about that now...weird.. The engine specs also show 2300 as max rpm....

 

[Simi 60]

I plan on having an engine survey completed on the Cummins QSM11 but would like to know from those that have this powerplant what are some possible issues at 1500 hours we may be facing?

.

I have a different cummins engine (nta855m) but 30,000 hours between rebuilds is often mentioned for mine.
It had under 4000 on it when we got it so it will live longer than me.

 

[smitty477]

Yes.. I see that as well and am calling someone about that now...weird.. The engine specs also show 2300 as max rpm....

The gear are not consistent on the spec sheets either - it would be pretty important to know the exact specs on the boat that was tested.

 

[Codger2]

If you want to cruise at 14 knots all day you should be looking at a different kind of boat. .

I have made that mistake several times since 1995. I now have the right boat!

 

[smitty477]

That goes with my comment about the choice of boats. The Nordic Tug will go fast but it and any similar boat will use a lot of fuel doing it. Going twice the speed doesn't use twice the fuel, it uses four times the fuel.

Hello Wes - in most cases I say "so what" to those types of comparisons.
This boat may be able to do 4 nmpg at 6 knots , 3 nmpg at 8 knots , 2 nmpg at 10 knots and 0.95 nmpg at 17 knots like my last boat did.
So you have the choice of speed and economy every time you cruise. And when you might like to uie the speed - like up the Hudson , or at hells gate or at the Race you just dial it up.
Its just a choice that you can make.

 

[Nomad Willy]

mvp,
Codger makes a good point.
If you actually have intentions of "all day at 14 knots" you should be looking at boat that will be more efficient at that speed. A planing hull or a SD hull closer to a planing hull will probably be better for you. A Camano comes to mind. Somebody makes a Camano descendant about 40' (Helmsman?) and it may come closer to 1/2 the fuel burn on a NT at that speed. Eight to 10 knots is where the Nordic Tugs shines. Get above that (probably 12 w the longer boats) and a flatter straighter bottom aft is better. And rocker at higher speeds I'm sure will promote bow high attitudes.
In the NT line I'm more familar w the 32 and it has rocker. I'm curious to know from those that do .. do the bigger NT's have some rocker? Very few trawlers do and I wish they did as much of the fuel efficiency talk on TF would not be necessary.

 

[mvp]

Thanks everyone for the comments on this power plant and suggestions for another boat.

This is the deal. We have been looking for a suitable floor plan in a Tug for a long time.. stumbled onto a 2000 NT in Anacortes just by accident. Has a dual staircase. It was only manufactured two years (I think). I told my wife it needed to have a flybridge. Guess what was moored one marina over? 2000 NT with flybridge..and the BIGGER engine.

So, at this point we are just trying to figure out what is a suitable offer and I'm trying to figure out the Cummins QMS11 635 power plant since it was not installed in many NT's.

I will just have to cruise slower and get used to it. Probably not at 14 knots. My wife is actually great at the helm so I may just let her pilot. I run an inboard jet on rivers on East Coast at 37 mph... a different beast. You don't want to know what the fuel flow is... I don't even look anymore... But dang it is fun! This NT is another type of fun that we have been waiting to do for a very long time.

I really only had one other question about painting the hull. Is this done every so many X years or do you inspect and then make a decision. I am kinda thinking if it has been in the salt for close to 18 years something will be needed.

Thanks and Thanks again for all the speedy responses!

Mike and Keri

 

[seasalt007]

I really only had one other question about painting the hull. Is this done every so many X years or do you inspect and then make a decision. I am kinda thinking if it has been in the salt for close to 18 years something will be needed.

Thanks and Thanks again for all the speedy responses!

Mike and Keri

I have never heard of an NT with a hull blister. Vinylester construction.

 

[Fletcher500]

MVP, like you, I previously went fast on a planing hull. It took some time to get use to the idea of going slow, but I am there now and often ran our Express cruisers at hull speed the last few years when we had one. Enjoying the view, and the environmental aspects of putting along at a low fuel burn is a good thing.

I have spent time on other websites where quite a people had the QSM11s in Larger EC's and I believe the overall majority really liked them.

Good luck with your potential buy.

 

[FF]

"or at hells gate or at the Race you just dial it up."

With a tide table one can zip thru Hell Gate or the Race at idle.

 

[smitty477]

"or at hells gate or at the Race you just dial it up."

With a tide table one can zip thru Hell Gate or the Race at idle.

Absolutely yes - we use the Eldridge tide and current tables to map out the trips as well.
If your goal is to travel from where we are in Northport up the Hudson you will find the currents to be a much larger problem if you cannot make a faster speed as they reverse in a couple of places. So if you time out hells gate there will be heavy current facing you for many miles before and after.
When we made those trips in our 34 Mainship we would need to reasonably take 2 or 3 days for the trip and there were less than great options on where to stay the night(s).
There is always a solution if you have the time - just pointing out that if you do not have the option to move faster than a 3-5 knots current can be a real planning issue.

 

[North Baltic sea]

Hi, I do not know what the NT-42 is the fastest speed. My NT37 is 18.5 kn 3050 rmp cummins qsb 380hp. The cruising speed can be kept at 14-15kn. When I bought my boat from Germany on time in its three days home about 600nm middle speed at 15kn 2600-2700 rpm Cummins qsb 380hp.3 fuel refueling and time 12-16 hours day trips.

Here's a small video on the my way home Baltic sea. The video speed ranges from about 15 to 17.5 cummins rmp 2600. The engine may be somewhat low power at high speeds because the waves are slowing down, and the surface starts to surf faster.


That trip, with waves rising about 3-4m(not this video) to the NT broaching wave at 19.5kn speed, and now I know it can not / should not go harder than max 18.5kn, note the same rmp 2600 my cummins

https://vimeo.com/236749780

 

[dhays]

Hi Dave,

Not in NT boats the bow does not aim at the heights at any speed, thanks to Lynn Senour's hull design for NT boats. Look this NT42 video https://video.search.yahoo.com/vide...h&age=1222944114&fr2=p:s,v:v&b=61&fr=sfp&tt=b

NBs

Thanks for the video link. While the NT bow definitely goes way up at the higher speed, not nearly as much as I might have expected.

 

[OldDan1943]

Looks like it will do 17 knots with 450 hp so your goal should be fine......
Nordic Tug 42: Sea Trial - boats.com

The limiting factors is how much fuel you carry and how much fuel you use at your desired speed.

You must also consider the physical fatigue factor of the you and your wife.

 

[sunchaser]

The very attraction of pseudo trawler (SD) designs from NT, AT, OA, GB and Beneteu amongst others is their ability to efficiently cruise above hull speed. Those of us with slow trawlers do not have the option to cruise all day comfortably at say 9 or 10 knots.

So those of us with Nordhavns, Selenes, KKs, various Taiwan brands DeFevers etc are relegated by design to the slow lane. For short jaunts it really doesn't matter. But for multi thousand mile summer trips it can be important. To whit, the journey of Alaska Seaduction and Pairadice this past summer. AK Seaduction smartly took advantage of his ability to fuel efficiently ramp it up.

For the above reasons, if the NT 42 passes inspection I'd say go for it and ignore the mumbo jumbo about "high" fuel burn when wide open. Fuel burn on this NT is at the owner's discretion. For our vessel there is no discretion. We are always relegated to the low gph lane, with it's specious bragging rights.

 

[OldDan1943]

I have a car that can travel in excess of 120mph. I do not feel the need to drive that fast.
I get better gas mileage and fewer traffic traffic tickets when I drive slower.

Same way with a boat. Just because your boat can go 20 knots does not mean you need to go that fast. Relax, go slower, enjoy the experience.

 

[smitty477]

The limiting factors is how much fuel you carry and how much fuel you use at your desired speed.

You must also consider the physical fatigue factor of the you and your wife.

Yes - we would get fatigued sometimes , that was one of the reasons we would speed up so we were not on the water for longer periods in certain situations.
But we could always slow down if that was a better choice.

 

[CDreamer]

Putting a boat of that size on the six small pads of that hydraulic trailer is a recipe for unseen structural damage to the hull skin!

I am just asking: Aren't the hydraulic pads just intended to keep the boat upright, while the boat's weight is resting on the keel?

I didn't realize those would put more pressure on the hull than "manually positioned" screw-jack type pads.