Forum: Construction, Maintenance & Refit
Today, 18:38
|
|
Replies: 6
Views: 153
|
|
Forum: Monohull Sailboats
Yesterday, 21:00
|
|
Replies: 13
Views: 567
Re: Hylas 46 polars
Wrong boat; go up one:
Hylas 46 (https://sailboatdata.com/sailboat/hylas-46/)
|
|
Forum: General Sailing Forum
10-04-2024, 15:33
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
That's an unusual definition for loading. It seems more like the definition of "efficiency." The former would generally entail a reference to the maximum capability of the engine. Common metrics are...
|
|
Forum: Monohull Sailboats
10-04-2024, 14:40
|
|
Replies: 13
Views: 567
|
|
Forum: General Sailing Forum
02-04-2024, 05:18
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
I can't believe I forgot one of the most important questions.
So here is NC's little summary box:
288384
So, the questions are:
- Which engine has higher loading*, the one producing more power...
|
|
Forum: General Sailing Forum
01-04-2024, 21:52
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Yes, I challenge this. But I'll ask again: how do you define "engine loading?" Without agreement on this rather important detail we'll most certainly keep talking past each other.
I don't see...
|
|
Forum: General Sailing Forum
31-03-2024, 20:34
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Uhhh, yeah, I've said many times that you could move to a more efficient point in the map.
Why didn't you quote the remainder of that paragraph?
|
|
Forum: General Sailing Forum
31-03-2024, 18:09
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Lots could be said about this article, but I'll keep it simple.
As Calder says on the bottom of the first page, bigger props are more efficient, so that kind of limits the usefulness of the whole...
|
|
Forum: General Sailing Forum
31-03-2024, 17:54
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
I never said I haven't read any of their work. There are at least two of Calder's books on the bookshelf on the boat right now. (I am not currently there.) I've read lots of Calder in books and...
|
|
Forum: General Sailing Forum
30-03-2024, 19:30
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
:thumb:
I have no problem with people doing whatever they want to their boat. It's their boat after all.
However, I do think what they do should be based on an informed opinion. There are many...
|
|
Forum: General Sailing Forum
29-03-2024, 19:55
|
|
Replies: 137
Views: 12,171
|
|
Forum: General Sailing Forum
29-03-2024, 19:30
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Yes. But I did more than that, I demonstrated it. But please show where it was flawed, I'd love to learn something.
Why? Please explain why/how, in your opinion, it changes. (As opposed to...
|
|
Forum: General Sailing Forum
28-03-2024, 21:28
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Which ones are diesel?
Not all engines, especially diesels, have the minimum SFC occur at the low RPMs shown in your figures. Perhaps many do, but not all.
For example, if you look at this Cat...
|
|
Forum: General Sailing Forum
28-03-2024, 21:08
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Yes, really.
I'm not an automotive engineer, but let's use the Saturn SL sedan and the engine that Adelie presented, and give it a go. I looked up some data (tires and gearing).
Tire size is...
|
|
Forum: Construction, Maintenance & Refit
22-03-2024, 22:33
|
|
Replies: 18
Views: 1,625
|
|
Forum: General Sailing Forum
22-03-2024, 22:17
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
:thumb:
:thumb:
No, I'm not suggesting that...I'm stating that. And I have about a dozen times.
To be clear, I am using "load" to be the same as power. %MCR. If you mean something else,...
|
|
Forum: General Sailing Forum
21-03-2024, 20:15
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Here you go:
287895
Note design point G1 on the calm water prop curve (curve 1, dashed) at 100% rated engine speed and 90% MCR on power. If you start over-propped on curve 2 (solid black) you...
|
|
Forum: General Sailing Forum
21-03-2024, 19:55
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
This is close, but not quite right, IMHO. Or maybe incomplete is a better description.
In many/most cases, they're not exactly the "SAME ENGINE." The same block and basic engine, yes, but they...
|
|
Forum: General Sailing Forum
21-03-2024, 19:37
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Ditto.
I can accept that we are now generally on the same page (or close enough that I don't want to repeat) with one big exception: you aren't changing the engine load by over-propping. The...
|
|
Forum: General Sailing Forum
21-03-2024, 09:37
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Yes.
That is a gasoline engine. So while the trends are similar, I believe the possible efficiency gains are much smaller (~half) with a diesel. Your lines show ~6.7% improvement, generally....
|
|
Forum: General Sailing Forum
21-03-2024, 09:25
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
Riiiight...
Me too, but you haven't presented any (conclusions or science, just some name dropping).
Do you know my credentials? Do you need to?
|
|
Forum: General Sailing Forum
19-03-2024, 21:53
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
This is too much of a simplification. It's more than that. It's: you do it (not overprop) for the health of the engine and to maximize the performance of the prop/engine system across the widest...
|
|
Forum: Rules of the Road, Regulations & Red Tape
12-03-2024, 09:50
|
|
Replies: 13
Views: 561
Re: IRPCS/COLREGS Source
I believe the document you're looking for is at the link provided by Kelkara. It's at the bottom of the first table (before the countries) under the "Text documents" line. See here:
287543
...
|
|
Forum: Rules of the Road, Regulations & Red Tape
12-03-2024, 08:49
|
|
Replies: 13
Views: 561
Re: IRPCS/COLREGS Source
Here are the USCG version:
NavRules (https://www.navcen.uscg.gov/sites/default/files/pdf/navRules/navrules.pdf)
|
|
Forum: General Sailing Forum
11-03-2024, 21:51
|
|
Replies: 137
Views: 12,171
Re: Diesel RPM?
That’s correct.
Thread drift is one of the things I don’t enjoy about this forum, but I’ll take the good with the bad.
Thanks to those who have contributed towards my original question.
As...
|
