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Spoons.... when do you use them ?

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spoons
12K views 61 replies 15 participants last post by  pedro 
#1 ·
I was washing off a spoon last night and had to say to myself. "oh that's how that works"

So when did people stop using spoons and on what types of boats was there a benefit ?







I posted them sideways so the water flow is easier to see. It's interesting that the spoon doesn't have to be deep into the water stream to change the flow path.

So when and why did they go out of favor, or are there some style of boats that still use them ?

Sleeper CP
Big Inch Ford Lover :)bulb
 
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#2 ·
Hmmm! interesting how the Keel (Spoon) drops drasticly before it starts its run upwards into the pump housing. dont know too many boats with such an abrupt keel like a spoon in your pics Jon. good topic though!
After this weekend i have a define revised list of todo's befor summer boating.
 
#5 ·
hell ive even heard of some people using a doubble spoon on the keel to load the intake ..... now i understand that a rounded surface { such as a spoon } will act like a suction cup when water flows over it. now { not to jack your thread jon, } does the water increase velocity over a rounded surface or does a back cut shoe do that ????:)bulb
 
#3 ·
Nice seeing you Todd.

I hope one of the smart guys will answer my questions.

Sleeper CP :)bulb
 
#4 ·
Shape and size of a spoon on each boat will change the intake charge as well as lift and ride attitude. It seems every boat responds differently even from the same manufacturer. I have changed mine quite a few times, trying to optimize the overall performance of the boat. I only go by GPS and seat of the pants, but we (Circle Jets) do run more than a 1/4 mile. I still think I have a bit more work to be perfect.
 
#6 ·
John,

you're kidding right?

you've not done the bottom of your boat? If not, don't change it, it seems to be working for you.

the "bubble" or "keel" or "entry" has to be done right in front of your intake ... otherwise you won't load your pump right.

why do you think you keep seeing everyones boats on here upside down? for fun? :)sphss


I'm sure Bennet might beg to differ if you say people have stopped using the "spoon" effect (as you call it) on jet boats.

B
 
#7 ·
Nope we are sanding them flat for the ultimate ride, trying to get them to run nose down. For example I saw a few jet boats running like hydros last weekend at the tommy tribute, must be some trick bottom work there J/K.

Seriously a tunnel is completely different then a v bottom, so bottoms should be done accordingly. I would think that if you didn`t know what your doing you could get your self in a world of hurt. Putting a big bubble or spoon on your boat without knowing what it will do to the ride attitude of your boat could get ugly.
 
#11 ·
[Sleeper, turn the spoon the opposite direction and you will have a more realistic example of the theory.
If I turn the spoon the other way that would be the inside of the spoon the shape on the bottom of the boat is convex isn't it ? If I turn it over it would be concave wouldn't it ? The water will still flow the same ?

Sleeper CP :)bulb
 
#14 ·
I suppose my tug boat is the hull that needs a spoon the most. A flatbottom, with a tall rise on the intake. I would imagine IF I added a spoon (of some sort), it would:
provide a little lift to the intake (the LAST thing I need right now without loading the pump better)
load the pump better
Granted this boat is a dinosaur and probably not worth the effort, but easily illustrates the principle and benefits
 

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#20 · (Edited)
I have a ramp loader in it now. I think a spoon would load the impeller better without adding air. I think the problem with the flat is as it airs out, it packs air in the intake. A spoon should create a high pressure area in front (moving any incoming air around the intake) , and the corresponding low pressure behind the spoon pull water into the intake.
 
#21 ·
I was washing off a spoon last night and had to say to myself. "oh that's how that works"

So when did people stop using spoons and on what types of boats was there a benefit ?







I posted them sideways so the water flow is easier to see. It's interesting that the spoon doesn't have to be deep into the water stream to change the flow path.

So when and why did they go out of favor, or are there some style of boats that still use them ?

Sleeper CP
Big Inch Ford Lover :)bulb
Hold on a minute, I have a Pie chart and a graph that could possibly illustrate the benefits and draw backs as well as performance effects of a spoon on a boats keel. BRB.

Cy
 
#23 ·
Cy do you have anything constructive to add ? ;)

Sleeper CP :p
 
#27 ·
I did a test of running a .500 keel and then going to .875 keel and no other changes. Biggest thing i saw was a ton more inlet pressure. Boat wanted a tottally differnent setup. Had to pull .350 of shim from the shoe.

edit.

Just wanted to add that the thing was able to run through lumpy water much better with the deeper keel, it protects the intake from air I think.
 
#29 ·
I did a test of running a .500 keel and then going to .875 keel and no other changes. Biggest thing i saw was a ton more inlet pressure. Boat wanted a tottally differnent setup. Had to pull .350 of shim from the shoe.
CS,

Current boat or old boat. Didn't you have a GW before you stepped up ?

Sleeper CP
 
#30 ·
No nothing constructive but while scrolling down, I did have a tought.

Adding the spoon also adds surface tension by increasing the amount of surface for the water to go over but at the same time probably reduces the surface area that is in the water on the outer edges of the boat by lifting the boat out of the water. The spoon forces the water to accellerate around the hump from the area of high pressure to an area of lesser pressure which happens to be where we need it, in the intake. I am sure having the water stream already arching up into the pump doesn't hurt either, taking less HP to lift the water up into the pump. I know of many boats that are utilising the spoon and Tom was looking into more variations of these for additional benefits. You could discuss some of these with Vic at desert Yacht Performance Marine he is another wealth of boat knowledge.

Cy
 
#31 ·
Hey thanks for the non-constructive input, Glad you didn't have anything to say it might have been 500 words ;)

Sleeper CP :D

Can you drawl me a picture of the lower pressure area ?
 
#39 ·
I conversation of bubbles, you may find the bump may help feed the pump, and go faster, but at the same time causes serious shut down issues. Dropped keels have worked out well, helping land the hull more gently on shut down.
 
#46 ·
yep, try steering a drop keeled boat with a spoon keel, they don't turn well over 100:)sphss we've got a tx20 in the family with a spooned drop keel by ervin capps. its a freak, flies super high in the water with alot of bow atitude, gets skeery sometimes, feels like you're on the edge of blowing over, but its just actually on the keel and level. i've had to turn it at 110:)st other than the steering issue, the boat always stays loaded, averages around 50psi over 100, no matter the water condition. we're building a twin turbo 496 for it now:)grn

 

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#41 ·
If I turn the spoon the other way that would be the inside of the spoon the shape on the bottom of the boat is convex isn't it ? If I turn it over it would be concave wouldn't it ?
I didn't make myself very clear. I should have said turn the spoon end for end, (handle down instead of up), but use the same side, (bottom of spoon). Does that help?
 
#42 ·
Yes. Small end towards flow wide end at exit...

Sleeper CP
 
#48 ·
lol, there's alligators in that lake, its a cove on broken bow lake in okla. what you're seeing on shore is the bottom of a mountain;) the lake is surrounded by mountains, clear cool water, and we get to run without baffles or water injection there. i think alot of west coast fellas would love to come to 1 of our dealios, 50+ dragboats show up just to cove race, no patrol hassle'n, everyone having a good time with a good attitude/atmosphere:)bulb

http://www.youngbloodjetboats.com/OUTINGS.htm
 
#49 ·
lol, there's alligators in that lake, its a cove on broken bow lake in okla. what you're seeing on shore is the bottom of a mountain;) the lake is surrounded by mountains, clear cool water, and we get to run without baffles or water injection there. i think alot of west coast fellas would love to come to 1 of our dealios, 50+ dragboats show up just to cove race, no patrol hassle'n, everyone having a good time with a good attitude/atmosphere:)bulb

http://www.youngbloodjetboats.com/OUTINGS.htm
again looks chingon! wish it were closer. Do you okees have to run water or baffles on all the ponds back there? For real are there snapping tortugas in the lakes and rivers. I have heard horror stories of those bastards in the lakes and rivers.


ps my river the rio grande doesnt have tortugas, we just have people that bite when the man chases us. lol
 
#56 ·
few more. i honestly believe if that hull had had some type of spoon or race bubble , it'd been alot fast on the top end. where we race its rough, so to keep the boat hooked, i was runnin deep and costing myself alot of mph for the trouble:mad::|err





 

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#57 · (Edited)
:)devil


you can see when the impellor gives up the ghost in this pic, it was a new aggressor a that got the veins straightened out,lol. was only 2hrs old in that pic, and the next day it was back on my work bench.i felt it go, but i stayed in it, i was winning:)


 

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