more help with plot for mystery

[cayucos]

Hello, I was here a couple months ago asking for info for a mystery I'm writing.

Back again, with some changes and new questions:

1. Could an undersea vacuum (on a dredge?) spray air/water into a sand bed with enough force to "sandblast" nearby kelp? I need the sand to be embedded in the stipe or fronds or even the holdfast of the kelp.

2. I know floating kelp can get entangled in a boat's rudder/propeller. I've also read that it can get caught in the "seawater intake" system. I have a very vague idea of how this intake system works.

What I need in the plot is for drift kelp to get caught in the propeller (that part's clear, I think). The boat captain clears off the kelp. The next day, the captain comes to think more seaweed might be caught elsewhere--I'm thinking in the intake system. Would/could the captain access the system onboard (as opposed to diving) to check to see if any bits of seaweed (as big as possible) are caught there?

I got a lot of great help last time I dropped by and appreciated it. Hope someone can lend a hand again.

Many thanks!

 

[QC]

Re: more help with plot for mystery

Can't help with #1 but seems very probable . . .

On #2, this is typical of what the "intake" thru hull would look like:

Above that may be a "sea strainer" to catch crap before it got into the pump and then the engine:

Typical symptom of a clog would be an engine overheat. If the clog was in the inboard strainer, the operator would close a water intake valve between the thru hull and the strainer, so she won't sink. Pull out the "basket" in the pic, and clean it. Usually would not clog the deal on the bottom badly, that might require a swim to clear . . .

Oh and the simple way to clear a propeller of kelp is somewhat heavy throttle in reverse. Very common procedure.

 

[cayucos]

Re: more help with plot for mystery

Thanks QC!

Very helpful to actually see the intake system. And now that I'm looking at it, I wonder how anything other than the smallest bits of kelp could get sucked in through the strainer. Also, is it possible that what gets caught would not overheat the engine?

I need a delay of a day or two between the discovery of the kelp on the propeller, and the suggestion that more kelp (bits) might be caught elsewhere.

As to throttling back to clear the prop, great for real-life boaters but I need my captain (who is rather stressed about other things) to get back to the dock, and only then notice the kelp on the prop. Possible? What about on the rudder or the keel or any other thingies? (sorry, I'm a landlubber writing about the sea!)

 

[DJ]

Re: more help with plot for mystery

Any good captain does not go overboard without doing the following:

1. Reverse prop shafts to try and clear the tangle.

2. Reverse and "drift" to let the tangle move off.

3. Any "good" captain would immediately know that he/she has an obstruction to his/her boat's handling. They wouldn't leave the dock knowing something is amiss. Again, read; "good captain".

But, that's NOT Hollywood.

 

[QC]

Re: more help with plot for mystery

I wonder how anything other than the smallest bits of kelp could get sucked in through the strainer. Also, is it possible that what gets caught would not overheat the engine?

Very definitely stuff could be in that basket and not immediately lead to an overheat. That's why it should be periodically checked which seems to fit, Also, if they were looking for evidence that would be the likely spot.

As to throttling back to clear the prop, great for real-life boaters but I need my captain (who is rather stressed about other things) to get back to the dock, and only then notice the kelp on the prop. Possible? What about on the rudder or the keel or any other thingies? (sorry, I'm a landlubber writing about the sea!)

It would be unlikely to have significant amounts on the prop and not know, that would make it unbelievable for me. The rudder and the propeller "strut" or associated hardware, yes. On the prop in any qty and not noticeable, not so much . . .

 

[QC]

Re: more help with plot for mystery

FWIW, you could easily have mud/sand from the dredging and kelp in the strainer basket . . .

 

[cayucos]

Re: more help with plot for mystery

Any good captain does not go overboard without doing the following:

1. Reverse prop shafts to try and clear the tangle.

2. Reverse and "drift" to let the tangle move off.

3. Any "good" captain would immediately know that he/she has an obstruction to his/her boat's handling. They wouldn't leave the dock knowing something is amiss. Again, read; "good captain".

But, that's NOT Hollywood.

Well, the captain is experienced, although not good (that is, a bad guy

So sounds as though I'd best entangle the kelp elsewhere...

Thanks.

Very definitely stuff could be in that basket and not immediately lead to an overheat. That's why it should be periodically checked which seems to fit, Also, if they were looking for evidence that would be the likely spot.

It would be unlikely to have significant amounts on the prop and not know, that would make it unbelievable for me. The rudder and the propeller "strut" or associated hardware, yes. On the prop in any qty and not noticeable, not so much . . .

The basket: sounds perfect, thanks. Follow-up question: would the stuff be in tiny bits? Or could it be bigger?

Yes, I see. You and DJ have convinced me that the prop won't work in this scenario. So I'll go with the rudder or propeller strut (gotta look that one up). Just to be clear, there can be a tangle of kelp on, say, the rudder and the captain wouldn't necessarily know it until he actually looked?

 

[cayucos]

Re: more help with plot for mystery

FWIW, you could easily have mud/sand from the dredging and kelp in the strainer basket . . .

Yes, that makes sense. But the dredging takes place several days before the scenario in which the kelp gets caught. That's why I need the sand embedded in the kelp. That will be the clue my protagonist, a geologist, follows.

I really appreciate all your input.

 

[QC]

Re: more help with plot for mystery

Tell us more about the boat, so we can help with the rudder and kelp stuff. I have been assuming a true inboard, because of your description of "intake". But there could be some inconsistencies here. How big? Application? Fishing, pleasure? Miami Vice? Will help us make this consistent with your story.

Yes, stuff in strainer would be small. Has to make it through the openings in the thru hull (1st pic)

 

[cayucos]

Re: more help with plot for mystery

Tell us more about the boat, so we can help with the rudder and kelp stuff. I have been assuming a true inboard, because of your description of "intake". But there could be some inconsistencies here. How big? Application? Fishing, pleasure? Miami Vice? Will help us make this consistent with your story.

Yes, stuff in strainer would be small. Has to make it through the openings in the thru hull (1st pic)

Firstly, re the strainer: looking at that pic I'm thinking a seaweed frond might make it through, lengthwise?

The boat: Actually, there are two boats. (sorry, this is getting complicated)

First boat is an anchovy fishing boat, as small as I can make it (prefer to have it handled by one or at most two people). This boat just gets kelp caught on the prop or rudder. It is abandoned at sea shortly after that, so no worries about engine overheating.

Second boat is a whale-watching boat. Standard size (whatever that is), holding about twenty passengers, crewed by two people. This is the boat that must return to the dock without the captain knowing the rudder is fouled, and there the captain finds and removes the kelp. Couple days later, the question arises if more kelp is caught somewhere...and that's where I came up with the intake system idea. The boat is at sea at the time and so there must be access to the strainer basket (or whatever works) from on board.

Okay, does this make any sense? Thanks!!

 

[QC]

Re: more help with plot for mystery

Both boats work with the components I imagined/posted. Yes, the pieces could get by the thru hull (bronze thing) and into the Sea strainer (basket thing). Yes can be inspected at sea. Need to shut off the water supply to keep her from sinking, but common to clean out while at sea.

When you complete that section(s) I'd be glad to proofread it for you for technical accuracy . . . PM me when ready and I can send an email address.

 

[Cofe]

Re: more help with plot for mystery

For the first boat, the kelp that is floating around, has a piece of old fishing net entangled and when it gets in the prop, the kelp and the net combined really snarl things up.

No suggestions for the second boat.

 

[cayucos]

Re: more help with plot for mystery

Ah, good idea about adding the net. Will consider that one.

Thanks!

 

[cayucos]

Re: more help with plot for mystery

Both boats work with the components I imagined/posted. Yes, the pieces could get by the thru hull (bronze thing) and into the Sea strainer (basket thing). Yes can be inspected at sea. Need to shut off the water supply to keep her from sinking, but common to clean out while at sea.

When you complete that section(s) I'd be glad to proofread it for you for technical accuracy . . . PM me when ready and I can send an email address.

Hooray, looks like I'm in business. And, actually, my landlubber geologist will likely be calling the pieces in question the bronze thing and the basket thing.

And thank you for the offer to read! I'm still only a quarter way through the first draft (had to go back and change some plot points that were beyond believability, sigh). When I get the relevant chapters finished, I'll PM you. Appreciate it.

 

[tswiczko]

Re: more help with plot for mystery

http://blogavenuenews.blogspot.com/2011/01/garbage-island-real-and-growing.html

Here is a link if you need a different method for debris to get in the prop

 

[cayucos]

Re: more help with plot for mystery

Yeah, I've been reading about that. Serious debris trap.

Thanks.