Many trucks have auxiliary power units (APUs) -- essentially small generators -- to power the AC and other house loads at rest stops. Some states have anti-idling laws.
The coolest recent development in marine propellers is toroidal propellers which are now commercially available and seem to perform significantly better than standard propellers: https://www.sharrowmarine.com/
For the most part the Sharrow props have not proven to be much of an improvement, particularly for the high price.
The tests that have shown "significant" improvements have frequently compared the Sharrow to a sub-optimal prop. Feedback from many actual users is that the gains are moderate over a narrow RPM range.
Do you have any more information/sources to share on this? I have an Eastern 18 powered with a Yamaha 60hp 4 stroke and I've been struggling to dial the prop right. I don't know off the top of my head what the specs of my current prop are but basically I feel like I'm not taking advantage of the engine's torque at less than WOT, so I basically just run it flat out. If I could extract just a little more thrust out of the prop at lower RPMs it feels like the engine would have enough grunt to make the boat plane in the mid-high 4000s instead of 5000-5200rpm where I currently run it. Ideally, given the bsfc/hp curves, I'd like to run the engine at a bit lower RPM, but the way it's currently set up at ~4600rpm it's not fully up on the step. I was (perhaps wishfully) thinking a little more efficient prop design might help.
The other thing I was thinking of trying is swapping in a different "high torque" lower unit with a lower gear ratio and running a significantly larger prop.
Sources are primarily boating forums, dockside conversations, etc.
In theory your boat in right in the sweet spot of recommended power range at 60HP. I don't know all the background on it, so all kinds of potential problems, but I would wager that "propped wrong" is unlikely to be the core culprit.
I'd start by getting it weighed and comparing your loaded weight to manufacturer specs. USCG requires positive buoyancy for hulls under 20'. This is typically achieved with using expanding foam in hull cavities, and that foam can have a tendency to absorb and hold water if the boat develops any failure of the seals around the bilge areas that are foamed. Reports of poor performance are very common for these sub 20' hulls because of waterlogging. If not a waterlogged hull, you might also just have too much stuff on-board.
To a lesser degree, a bimini can also have an adverse affect on speed/planing, if it's acting like a parachute. Not sure if you have a bimini, but if so it's worth trying a run with it up vs. down.
I'd also look at how your outboard is mounted. It's not clear if it the outboard from the factory, or if the boat has been repowered. Outboards being too high, too low, etc. are pretty common issues that can also majorly impact performance.
That's a few thoughts that comes to mind off-hand.
Yeah, you're likely right it probably makes sense to just run it rather than trying to optimize further. As for excess weight, there is some--mine is a rare variant that has a small cuddy cabin forward, and that thing is really wet and needs to be completely rebuilt. A previous owner's refit of the decks removed any flotation there may have been originally, but also introduced a lot of unsealed wood which is now wet and heavy. It needs a deck job soon.
The boat was re-powered under my ownership. I'm pretty confident the motor height is correct based on a variety of observations and measurements, so I don't think there's really anything to adjust there.
I wouldn't say I have a complaint with the boat's performance, more like trying to get the engine to run at cruise in a more efficient range of the bsfc/hp map, which may be a tall order at 60hp. To your point, though, if I can shed a couple hundred pounds in the refit that could very well do it.
That website seems to no useful information; only marketing speak about how great it is... Do you know of a good source on how toroidal propellers work and the engineering behind them?
> In the centuries after Archimedes invented the Archimedes' screw, developments of propeller design led to the torus marine propeller... it was invented in the early 1890s
Propellers (both marine and aero) are just spinning wings. If you picture a 2D airfoil like you might see in one of those "intro to lift" diagrams, all the flow is in what we call the chordwise direction, that is the flow is entirely along the axis of the wing's chord (leading edge to trailing edge).
A real 3D aircraft, however, has a fuselage. Similarly, a prop has a hub and the tips of each blade are spinning faster than the roots. The tl;dr of this is that real 3D lifting surfaces typically exhibit a mixture of chordwise and spanwise flow, which causes wingtip vortices to form[0], resulting in induced drag/induced power loss.
For a given amount of thrust the total amount of momentum that the prop transfers to the fluid is fixed. The tip of a conventional prop ends abruptly which causes a large pressure gradient and a strong vortex. A toroidal prop's shape causes the pressure gradient to be broader and less concentrated, therefore the wake vorticity is distributed over a larger region, reducing peak swirl velocities and lowering the kinetic energy lost to vortex formation (and to cavitation).
If that's machined, that's impressive. I've seen some crazy 5-axis CNC examples, and it's usually some bladed turbine fan. Not sure how many axis (axii??) this would require, but it looks cool nonetheless.
Packaging. Boxes, shippers, pallets, parts transports for use within automotive and other factories, etc. Very little direct to consumer or display stuff.
Analysts use packaging companies as a canary for manufacturing in general.
Interesting! I am familiar with this space as we developed a software tool [0] to optimize packaging based on 3D packing technology we developed. If it is relevant to you, happy to chat!
We currently use ArtiosCAD and TOPS pro for load and pallet optimization. I'll check out your software and forward over to the people-that-sign-the-checks.
"Authorities have investigated whether his death could be connected to this weekend's Brown University shooting and, at this point, a senior law enforcement official briefed on both cases told ABC News there is nothing to suggest they’re connected."
Authorities and the university have also been asking for tips but then flipping the script as soon as they get them: "Accusations, speculation and conspiracies we're seeing on social media and in some news reports are irresponsible, harmful, and in some cases dangerous."[]
Also worth noting... at one point the arrested the wrong guy.
They have no clue. And become hostile when people try to come up with one. While scrubbing student profiles and simultaneously claiming they have no knowledge of doing so. The whole thing is a total clown show and nothing said by the authorities is to be believed without independent verification.
Without further context, I don’t blame them for being hostile towards “Accusations, speculation and conspiracies…on social media and in some news reports”. Remember the Boston bombing? Tips shouldn’t be public.
Tips should be "public" in this case because that's the only way they get noticed enough to garner attention. Wouldn't surprise me if "homeless man" was ignored by the cops if he tried earlier, or "homeless man" was too afraid to approach them directly because of how cops treat the homeless.
Well maybe they should have been a bit more open to "conspiracies" since they're now saying they think they're connected and that they found a link of the same make/model car at both. Seeing as the "homeless guy" who remembered the plate was seemingly ignored for 5 days, he should have just blasted it on X.
Absolutely useless without a name and reputation on the line. It's an absurd to publish that multiple academics killed within an hour drive within one week have "nothing to suggest they're connected".
Are you from Boston / have you lived there? I do, and thank you for your concern. But this is confusing to say the least.
1. No one should be stupid enough to put their name and rep on the line, in a fluid situation, where there’s 0 idea who did the first anyways, for days now.
2. Dunno what you mean by academics, students and professors? Usually academics refers to professors / grad students / has a job at university related to teaching, but Brown victims weren’t professors. Hard to see how that indicates a connection.
3. It’s a real stretch to put Providence to Brookline at a 1 hour drive. In general, it’s two different worlds, so it’s strange to use it as a clear indicator they must be related.
4. If it’s obvious they’re connected, and making any claim of probability re: their connection should require putting your name and reputation on the line, what’s your name?
You are demonstrating a fundamental misunderstanding of trust. Aaron Katersky and Josh Margolin put their name on the line because without that you wouldn't know the provenance of the information and wouldn't know if you should trust it. Citing an unnamed officer making claims that they have insufficient evidence for is not good journalism, so their reputation takes a hit. The officer also deserves this reputational hit since they are making the unsubstantiated claim.
To be very clear here, the claim is that "there is nothing to suggest the two sets of predmeditated murders within a week within an hour are related". The fact that they're the same demographic, high profile, using the same weapon, close in proximity, and close in time are all concrete things that relate them. It is embarrassing to state otherwise, so the officer was not named. However the reporters are not immune to this, so they take the hit.
I am not stating the positive "they are related", I am refuting the negative "they are unrelated".
And as for my identity: I am not a reporter or public official. You don't need to and shouldn't use me as a source of truth. I am a member of the public applying logic to facts. I am closer to this event than you but I won't say more. As a member of HN who respects privacy I'm sure that should be enough for you.
You aren’t refuting a negative because the statement isn’t “they are unrelated” the statement is “(with current information) there is nothing suggesting they are related”
If you’re close to the situation, and have a substantiated reason to believe the claim that there’s no current information suggesting they’re related is inaccurate, you should be able to back that up. Except we both know you can’t, because you’re attempting to refute something that wasn’t actually said.
Other comments cover the “logic” being applied here. Dunno who those two names are. I’m genuinely worried about your grip on reality based on your writing, I don’t say that lightly and am very, very, serious, to the point I’d prefer to eat downvotes and offend you than hide that and possibly contribute to you worsening.
I hope you’re extremely close to one of these events and are extremely distraught, even though that’s tragic, because it would indicate you’re not just comfortable disassociated from reality.
Note the difference in your approach this morning versus now, to wit, you this morning: “ We have no info but he was the department head of the MIT PSFC. It's easy to imagine a deranged individual picking a high profile target by browsing MIT's website. Or it was a domestic dispute or road rage or any number of things that would drive someone to shoot someone in their home.
We have no information and can only speculate.”
The gaslighting is touching, but I hadn't had a mental shift between the morning and evening. I had a big response to a public official lying. The right answer (and officers that were on the record actually said this on Tuesday) that "all options are on the table". You'll see from subsequent statements today that ABC's prior publishing of the statement that "there is nothing that suggests the Brown University and MIT murders are related" was baseless and untrue.
Not only did the public official lie, but was given voice and reputational cover by ABC. This is deserving of the criticism I give it.
"Gaslighting" - I came back to note you were right. Also, you weren't being gaslit, and you were incoherent. You could have replied to any one of us with anything explaining yourself and didn't. Like, the same weapon one was especially bizarre. Note that "No indication" is same as "all options are on the table", as was repeatedly noted to you.
>4. If it’s obvious they’re connected, and making any claim of probability re: their connection should require putting your name and reputation on the line, what’s your name?
Steve Lookner?
authorities believe Brown University shooter used rented vehicle that is same make and model of car connected to killing of MIT professor"
One was a home invasion that may or may not be related to the victims work on fusion plasma. It is very likely unrelated to that work.
The other was a mass shooting style event that targetted an exam preperation review hall populated by econ students and led by a 21-year-old teaching assistant.
It's a stretch to connect an isolated murder of a field advancing physics researcher and a hall full of students just because all the victims are involved in book learning.
Possible connection, sure. At an improbable stretch.
ChatGPT can certainly knock up a Clancy like novel here, no doubt.
put another way, is there any sort of proof that this guy wasn't banging his neighbour's wife, or embezzling funds, or otherwise doing something shady?
On the off-chance that someone believes that there is border security between US states but that these states are an exception.
The US doesn't have border security between states.
The closest thing to an exception is the "don't bring agricultural products into California" stations. However, there's a bypass lane for folks who stayed within 10 miles of the border, and no one checks whether someone is using that lane inappropriately.
This is my theory as well. A google search for the late prof's name returns a .ir website at the top of the result for some reason. It's a tragic loss for the world and his loved ones as are the victims of the brown incident.
No need to apologize! It was totally rational to assume that these two events were unrelated. It is a wild sad story and we'll likely learn about the motive over the coming weeks. This story hit me particularly hard as I live about a 3 minute walk from the victim's house in the Brookline area.
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