RESPONSE LX HOW SHALLOW CAN YOU GO

[Lakenut]

I remember back in college, one of the comp lakes in the state was rather shallow. Wasn't uncomon for the ski to hit bottom when being pulled up. Re-rides were often given when skiers still had mud stuck to the fin at the end of the run

Running shallow in muck wouldn't bother me that much as long as there were no stumps or rocks to be found. Soft objects not so bad. Hard ones very bad. The lake I have a slalom course on is over populated in turtles. Kind of makes you kringe when you hear that distinct thud on the hull.

[tvano]

I remember back in college, one of the comp lakes in the state was rather shallow. Wasn't uncomon for the ski to hit bottom when being pulled up. Re-rides were often given when skiers still had mud stuck to the fin at the end of the run

Running shallow in muck wouldn't bother me that much as long as there were no stumps or rocks to be found. Soft objects not so bad. Hard ones very bad. The lake I have a slalom course on is over populated in turtles. Kind of makes you kringe when you hear that distinct thud on the hull.

the fin on my ski hit a turtle ... that woke me up!

[martinarcher]

lots of people run in waist deep water in coves without even realizing it at our lake. Swimming some of the coves was a real eye opener for me. Although our lake is pretty well controlled it does get low at times. For us the big worries are stumps as it is a hydro empoundment lake in land that was formerly wooded and when the water is low you "find" the stumps you have been clearing by a couple of inches but never knew were there.

That's exactly what our lake is. You really have to know it well or you can get in trouble fast.

eyepeeler - good to know you got you turn around spot figured out and pretty well cleared out.

[Malibudude]

I can tell you that a RLX can't operate in depth of 2'.....

[eyepeeler]

I can tell you that a RLX can't operate in depth of 2'.....

Define operate...idle, cruise, spin on plane, start, all of the above?

[Malibudude]

Define operate...idle, cruise, spin on plane, start, all of the above?

I'd have to say all the above, but it was about 20' from start and only myself in the boat pulling a skier. Then after shut down it still hit...

[eyepeeler]

I'd have to say all the above, but it was about 20' from start and only myself in the boat pulling a skier. Then after shut down it still hit...

I would guess that on shutdown you are going to draft more than 24". Maybe up to 36".

[waterborne]

When a boat enters shallow water, "Squat" comes into play. The hull will want to Squat toward the bottom. This affect on a small boat could be up to a foot. On larger ships with a displacement hull, it can be several feet. Other factors will be, more rudder to turn, more HP to maintain speed, longer stopping distance. The boat will handle different in shallow water. The rule of thumb for shallow water, is twice the draft.

[barefootpaul]

When a boat enters shallow water, "Squat" comes into play. The hull will want to Squat toward the bottom. This affect on a small boat could be up to a foot. On larger ships with a displacement hull, it can be several feet. Other factors will be, more rudder to turn, more HP to maintain speed, longer stopping distance. The boat will handle different in shallow water. The rule of thumb for shallow water, is twice the draft.

"Squat" can someone explain the physics of that

[waterborne]

When the bow passes through shallow water, the water makes a static hole. When the stern reaches the static hole it "Squats" into the hole. For example; In deep water you boat may need 18 inches, In shallow water, while moving, you might need 24 inches. Several factors will play into this; displacement, block coefecient, horsepower being produced, speed, under keel clearence, Hull type. There might be more factors, but I cannot think of them right now. But it comes down to this, if you need say 2 feet to run on plane in deep water, your draft will increass in shallow water. The only way to reduce the effect from this is to operate the boat as slow as you can while in shallow water.

This might help

http://en.wikipedia.org/wiki/Squat_effect

[eyepeeler]

When the bow passes through shallow water, the water makes a static hole. When the stern reaches the static hole it "Squats" into the hole. For example; In deep water you boat may need 18 inches, In shallow water, while moving, you might need 24 inches. Several factors will play into this; displacement, block coefecient, horsepower being produced, speed, under keel clearence, Hull type. There might be more factors, but I cannot think of them right now. But it comes down to this, if you need say 2 feet to run on plane in deep water, your draft will increass in shallow water. The only way to reduce the effect from this is to operate the boat as slow as you can while in shallow water.

This might help

http://en.wikipedia.org/wiki/Squat_effect

What about spinning on plane? When I am skiing behind the boat and it makes a tight spin as I stated in earlier posts, it looks like the stern is sliding and riding high on the water.

[tvano]

i'll provide todays entertainment.

i'm going to go out on a limb here so you guys just beat me up as you see fit.

i'm thinking that the 'squat effect' is not going to be the same on a planing hull as it is on a displacement hull.

or, to recognize that a planing hull may operate in a displacement mode, the squat affects a hull that is in displacement vice planing.

is shallow water going to have an affect on a planing hull? probably. but i'm not buying that there will be much (or any) of that 'squat'.

after reviewing that wikipedia item i would go along with their conclusion in a displacement hull. no problem.

planing hull? not so much. consider an extreme; that bass boat with a 300 hp outboard at wot. the only part of that boat that is wet is the prop (and the operators cheeks from the wind driven tears). you figure that the attitude of that hull is going to be different in 1' of water than it is in 120'?

i've been wrong before. i guess if i'm all wet on this then "i just don't know squat". bring it on.

Edited January 28, 2011 by tvano

[barefootpaul]

Tvano, I think you are right... I can't give you an equation to prove it, but my gut says your right...

Is anyone able to do the squat math on a Response? From my guesstimation, based off the Oasis of the Seas squat numbers, a Response would never squat anywhere near an inch...

[eyepeeler]

Also, with all tournament boat hull and underwater drive technology, the faster the boat goes(34.2 mph), the bow lowers and the stern raises delivering the SV23 Diamond great slalom wakes.

[85 Barefoot]

When the bow passes through shallow water, the water makes a static hole. When the stern reaches the static hole it "Squats" into the hole. For example; In deep water you boat may need 18 inches, In shallow water, while moving, you might need 24 inches. Several factors will play into this; displacement, block coefecient, horsepower being produced, speed, under keel clearence, Hull type. There might be more factors, but I cannot think of them right now. But it comes down to this, if you need say 2 feet to run on plane in deep water, your draft will increass in shallow water. The only way to reduce the effect from this is to operate the boat as slow as you can while in shallow water.

This might help

http://en.wikipedia.org/wiki/Squat_effect

The irony of that effect, if true in our applications, is that it is well-known that wakes are harder to beef in shallower water.