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Old 12-15-2018, 10:56 AM   #81
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Had you ever considered a VPP for the wing engine instead of the folding prop?

I haven't. I suspect it would be way too expensive. From what I've heard, I think the prop would be more than the engine and grear
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Old 12-15-2018, 01:56 PM   #82
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Thanks for the updated pictures. Interesting. me personally, I have never liked boats that store their dink on the bow. Just my preference.

Question regarding windows. Are your windows set in a frame or are they the new design of frame-less windows that I am seeing on RVs and some new boats?
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Old 12-15-2018, 04:39 PM   #83
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Nice revisions, especially the bigger ER door. Wonder if pop out handles would work for the side access and some Stainless steel step protectors would be a classy touch.
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Old 12-15-2018, 06:45 PM   #84
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Nice revisions, especially the bigger ER door. Wonder if pop out handles would work for the side access and some Stainless steel step protectors would be a classy touch.
Time to drop your drool towel....
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Old 12-16-2018, 09:58 AM   #85
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New post on the engine selection Adventures of Tanglewood: Mirror, Mirror, on the Wall, What's the Fairest Engine of All
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Old 12-16-2018, 10:00 AM   #86
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Originally Posted by Alaskan Sea-Duction View Post
Thanks for the updated pictures. Interesting. me personally, I have never liked boats that store their dink on the bow. Just my preference.

Question regarding windows. Are your windows set in a frame or are they the new design of frame-less windows that I am seeing on RVs and some new boats?

I had some reservations about the forward tender storage too. But in the end favored my own comfort so went with the aft pilot house.


The windows are all "bonded" glass, set right into the fiber glass mold. It's the same as car windshields, and get rid of the aluminum frames that inevitably corrode.
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Old 12-16-2018, 10:01 AM   #87
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Nice revisions, especially the bigger ER door. Wonder if pop out handles would work for the side access and some Stainless steel step protectors would be a classy touch.

I'm getting lots of good ideas on handles for the molded "ladder".
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Old 12-17-2018, 12:50 PM   #88
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Just saw your latest blog post on the step handles, so I'll chime in here on my thought...

I pictured the hand holds oriented as you have them, parallel to the steps, but positioned at the lower edge of every other toe hold. This has the effect of allowing the handle to be used to extend the toe hold with a place to rest the heel of your foot as you progress up and down the hull. It may also make it easier for your foot to 'find' the hole as you descend the hull.
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Old 12-17-2018, 06:04 PM   #89
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Just saw your latest blog post on the step handles, so I'll chime in here on my thought...

I pictured the hand holds oriented as you have them, parallel to the steps, but positioned at the lower edge of every other toe hold. This has the effect of allowing the handle to be used to extend the toe hold with a place to rest the heel of your foot as you progress up and down the hull. It may also make it easier for your foot to 'find' the hole as you descend the hull.

My wife and I were discussing this same idea earlier today. The up-side, as you say, is perhaps a bit more to put your foot on. The down side is that the grab bars will have to carry a lot more weight, and be more subject to working loose.


It's likely going to be a while before I settle on anything. Perhaps not even until the boat is state-side and I can actually pull along side in a tender.... But by all means keep the ideas coming...
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Old 12-17-2018, 06:16 PM   #90
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I've got a metal step mounted between my swimstep and my rail gate on my transom. (no transom door on Hull #1) It's been there for 41 years and is still going strong. I've had some big boys use that over the years!

If Marshall Boats can do it, no doubt Nordhavn can, too.
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Old 12-17-2018, 07:42 PM   #91
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TT, Have you made a decision on your main engine? The last blog entry I read had it down to Cummins, Deere, or Skania. I went to the Cummins website and the legacy N-series continuous duty engines as you'd find in salmon seiners and other big workboats are no longer
available. Can't meet tier 4 numbers? I've heard good things from Skania users in Alaska.
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Old 12-17-2018, 09:10 PM   #92
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TT, Have you made a decision on your main engine? The last blog entry I read had it down to Cummins, Deere, or Skania. I went to the Cummins website and the legacy N-series continuous duty engines as you'd find in salmon seiners and other big workboats are no longer
available. Can't meet tier 4 numbers? I've heard good things from Skania users in Alaska.

Adventures of Tanglewood: Mirror, Mirror, on the Wall, What's the Fairest Engine of All
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Old 12-21-2018, 07:21 AM   #93
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Twisted: I've been digging into your old blog entries. There's lots of good info to soak in! Will you be bringing the new 68 to Mass? I'd love to see you coming through the Cape Cod Canal!
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Old 12-21-2018, 07:51 AM   #94
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Could you mention where you obtained the data on heat rejection?
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Old 12-21-2018, 08:36 AM   #95
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Could you mention where you obtained the data on heat rejection?

The heat rejection data is in the engine performance sheet, or technical data sheet, pretty readily available for all engines.


Attached are the data sheets for the three engines I was considering.
Attached Files
File Type: pdf Technical-Data_Issue-13.pdf (2.46 MB, 15 views)
File Type: pdf 6135SFM85_ALL.pdf (199.2 KB, 11 views)
File Type: pdf QSM11FR20918.pdf (162.8 KB, 11 views)
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Old 12-21-2018, 08:40 AM   #96
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Twisted: I've been digging into your old blog entries. There's lots of good info to soak in! Will you be bringing the new 68 to Mass? I'd love to see you coming through the Cape Cod Canal!

No plans to. We will be south when it's cold, then up in Canada when it's warm. Then off to Europe for a few years. When done exploring, we plan to settle the boat long term in the PNW.
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Old 12-21-2018, 09:38 AM   #97
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The heat rejection data is in the engine performance sheet, or technical data sheet, pretty readily available for all engines.


Attached are the data sheets for the three engines I was considering.
Surprised that the differences can be so large. Not really familiar with diesel engine data sheets and am having a hard time making an apples to apples comparison. Would have expected the differences between engines to be under 30%. Notice Scania states their figure are based on 25 C degree water and 1013 mbar. Deere mentions 32 C degree water (kind of) and omits the mbars. Cummins mentions 25 C degree air temperature and I failed to see a mention of water temp. Still having a hard time seeing the kind of differences you quoted. Sorry, not trying to be quarrelsome but just to understand.
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Old 12-21-2018, 02:07 PM   #98
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Surprised that the differences can be so large. Not really familiar with diesel engine data sheets and am having a hard time making an apples to apples comparison. Would have expected the differences between engines to be under 30%. Notice Scania states their figure are based on 25 C degree water and 1013 mbar. Deere mentions 32 C degree water (kind of) and omits the mbars. Cummins mentions 25 C degree air temperature and I failed to see a mention of water temp. Still having a hard time seeing the kind of differences you quoted. Sorry, not trying to be quarrelsome but just to understand.

Do you see the entries for each for ambient heat rejection in each spec? They all call it something a little different. Scania lists for a lot of different power ratings, and I have highlighted mine on page 25. All engines' performance are at 25C ambient.


Here's my best take on the differences, lifted from teh comments section of the blog entry:

Yes, it's all manufacturer supplied data, meant for people designing the engine into some application where it needs to be cooled. So although I too am surprised by the wide ranging numbers, have to believe they are the most credible data available.

And I agree with you on the fundamentals for heat rejection, i.e. surface area and surface temp. On first inspection I would arrive at the same assumption too, namely all engines have roughly the same surface area, and all have surface temps approximating coolant temp. My previous Deere demonstrated exactly that, with IR surface temps across the engine in the 170-200F range, i.e. coolant temp, give or take.

Here are the things that I expect contribute to the difference, but I can't quantify any of them:

1) Any parts that are not coolant jackets, especially exhaust parts, can run significantly hotter. On some engines, for example, the pipe stubs coming off each exhaust port are not jacketed until they enter the main exhaust manifold. Those pipe stubs run real hot, and the paint is always discolored on them. But as best I can tell, the exhaust manifolds and all three engines are fully jacketed.

2) Turbos are another example, where some are coolant cooled, and others are not. But the un-cooled turbos are always insulated. Ironically, the Deere is the only engine of the three with a coolant cooled turbo. Both the Scania and Cummins are dry and insulated. So perhaps the insulated turbos reject less heat? It's possible, but I won't know until I run it and can measure the insulation surface temp.

3) One of the hottest parts is the intake air pipe exiting the turbo and leading into the after cooler. On the Scania it's maybe a foot total length. Perhaps the others are longer and/or run hotter?

4) The after cooler is another big one. On the Deere, it's a coolant cooled aftercooler, so the whole thing runs at or above coolant temp, and it a large mass with large surface area. On the Scania it's sea water cooled, so I expect runs at a much lower surface temp.

5) The Scania is a very tightly packaged engine, and physcially a bit smaller than the Deere. As such, perhaps the unfolded surface is measurably smaller.

Looking at the specs, I see now that they tell a significant part of the story. Both engines send almost identical amounts of heat out through their combined cooling system, and ambient rejection. The Deere is a bit less at 197kw coolant, and 40kw ambient for a total of 237kw. The Scania is 227kw through the coolant, and 14kw to ambient for a total of 241kw.

The big difference is that the Scania gets rid of a lot more heat via the cooling system rather than the ambient air.

It's also worth noting that the difference between the ambient heat rejection for the two engines is only about 10% of the total heat being carried away from the engine. So a small shift in how the heat gets carried away can make a significant difference in the absolute number for the ambient heat.
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Old 12-21-2018, 04:30 PM   #99
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Here is a "cold side" turbo temp at full load in 55* air. In a high ambient temp. over 400* is normal.



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Old 12-21-2018, 06:33 PM   #100
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No plans to. We will be south when it's cold, then up in Canada when it's warm. Then off to Europe for a few years. When done exploring, we plan to settle the boat long term in the PNW.
Okay. Well it's still nice to see your Gloucester, Ma location listed.
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