Boat draft

billnpat

New Member
Nov 15, 2009
3,610
Lindenhurst N.Y.
Boat Info
Twin-Zeus-Cummins QSC 600 (T-574 hp - 420 kW) Zeus Propulsion includes Helm joystick, Onan 21.5Kw di
Engines
Twin-Zeus-Cummins QSC 600 (T-574 hp - 420 kW) Zeus Propulsion includes Helm joystick, Skyhook® Stati
What exactly is boat draft??
our boat draft is 36"
does that mean we only have a 36" difference between the bottom of the props and the sea bed???:huh:

Yesterday when we got to close to the shore with the wind pushing me, i saw 1' 6 " on the helm depth finder..
scared me half to death, but did not ground..
i may have hit mud, but i did manage to pull away.....
 
Bill,
Draft is amount of water the boat needs not to hit ground. Your depth finder measures the amount of water below your hull
 
chances are your depth finder is set to tell you how much water is under your keel.

your draft is how much distance from the waterline to the lowest point under water. your rudders or props which ever is lower on your boat

would play with depth finder and make sure of setting before you need it again, bill

i set mine to give an alarm when in 6ft of water and have it zeroed to drives all the way down. it more important to me to know whats under props than the actual water depth
 
would guess that at a foot and a half a good wave surge and you would have bumped bottom
 
Bill,
Draft is amount of water the boat needs not to hit ground. Your depth finder measures the amount of water below your hull

i wonder if the props are higher than the bottom of the hull??

i wish i had a side view drawing or such of the hull bottom, and bottom of the props, so i could understand what it means to the props when i see 1' 6" of depth on my finder....:huh:
 
chances are your depth finder is set to tell you how much water is under your keel.

your draft is how much distance from the waterline to the lowest point under water. your rudders or props which ever is lower on your boat

would play with depth finder and make sure of setting before you need it again, bill

i set mine to give an alarm when in 6ft of water and have it zeroed to drives all the way down. it more important to me to know whats under props than the actual water depth

We have the same boat. its very important to me to know the depth under the props .how is that alarm programmed??
 
would guess that at a foot and a half a good wave surge and you would have bumped bottom

Would my props been higher as not to hit ???

at a 36" draft and 1'6" of depth finder levels???

When i'm looking at my depth finder, i'm imagining that the props are at that distance before grounding out

wrong? :huh:
 
Actual clearance under the props depends upon a lot of variables........size prop, dead rise, beam, depth of pad on the hull bottom. The safest way to determine yours, unless another 310DA owner has already done it, is to get under the boat with a tape measure and level and see if/how far the props protrude below the pad.

Depth sounding equipment has dafult settings that you can over-ride to offset for the heigth above the boats bottom the transducer sits. My depth machines are made by Furuno and B&G, both use metric measurements and the offset sets in decimal meters. The offset is in the set up menu for mine.........
 
Actual clearance under the props depends upon a lot of variables........size prop, dead rise, beam, depth of pad on the hull bottom. The safest way to determine yours, unless another 310DA owner has already done it, is to get under the boat with a tape measure and level and see if/how far the props protrude below the pad.

Depth sounding equipment has dafult settings that you can over-ride to offset for the heigth above the boats bottom the transducer sits. My depth machines are made by Furuno and B&G, both use metric measurements and the offset sets in decimal meters. The offset is in the set up menu for mine.........

Thanks Frank,

Guess ill have to wait to the end of the season when boat is out of the water to figure out just how much footage as to not touch props with the bottom by looking at my depth finder

Bill.....
 
I am guessing the the lowest (deepest) point on your boat may be the rudders. On mine they extend below the props (which sit in somewhat of a tunnel).
 
You don't swim................?


Not in this water.....maybe when we trip on down to the clear waters of fla....:thumbsup:
 
On my 320 - the lowest reading I can get on the boat in calm shallow water is 1.3 ft and at that point the rudders are still above the bottom. 1.6 feet and it is plenty of water for trying to find a place to anchor for the day. I boat in the Mississippi and I just dove under the boat to find where the rudders are at - with the different depths. When I leave I usually pull the anchor up manually and let the boat out to a little deeper water and then get on the boat to retrieve the anchor or with a group somebody moves the anchor back to deeper water and then I fire up the boat.
 
Bill you might want to get a mask or two to keep on the boat. In case you have to free a tangled prop. Also I find it fun to just dive down when we are anchored just to get comfortable down there.

I would bet/guess your previous owner set up the keel offset on the depth sounder so as to measure the distance from the lowest part of the boat (or their best guess) and the bottom. You don't have to make contact with the bottom to dredge up some mud. Just being in shallow water due to the thrust of the props and their direction will churn up some mud/sand.
 
We have the same boat. its very important to me to know the depth under the props .how is that alarm programmed??
bill;we have the same boat but big difference in drive set ups.

yours is fixed and no way to move up. mine are able to be raised if i encounter shallow water.

all my stuff and the new boat is now 800 miles away so i'm not going to be much help. i haven't played with the ray-marine depth gauge that came on our boat to remember how to tell you any setting.

one thing you can try is, on calm still day, get an exact sounding from the water line to the lake bottom. compare this number to what you depth gauge is reading.

this should give you a good idea of where your depth gauge is zeroed. chances are you will either match numbers, meaning your zeroed at water elevation or will be 3 ft short on your depth gauge which is telling you it has been zeroed at the bottom of, guessing from the one i have seen out of the water, your rudder.

if the latter is the case you still had a foot and half of room below you rudder-props
 
i wonder if the props are higher than the bottom of the hull??

i wish i had a side view drawing or such of the hull bottom, and bottom of the props, so i could understand what it means to the props when i see 1' 6" of depth on my finder....:huh:

This must be pretty damn near the same as yours.

4590689964_2db988d8d4_o.jpg
 
Spoke with a Sea RAY tech yesterday at the marina....Who said he would come by this week and check my depth finder , and said the draft is the amount of water i need to get up on plane...

Also looked at a 1999 310 inboard on blocks yesterday which is most likely like mine, and the props where a good 6-7" lower than the bottom of the hull, and even with the rudders

not sure if mine is the exact same...
 
Draft is the depth of the water required to float your boat. It is the distance from the actual water line to the lowest point on your boat. That lowest point could be your keel, props or rudder for example. Your tech may know what he means but the way he's telling you doesn't make sense.
 
hey bill, Boating in the "GREAT SOUTH PUDDLE", i set mine to 3' i have the same draft as you but dont want to take any chances, problem is the great south bay is not much deeper than 3' haha, I just installed a new transducer for the new garmin chartplotter so i have a second ducer i dont trust the factory installed on it seems to go wacky :huh:
 
Draft is the depth of the water required to float your boat. It is the distance from the actual water line to the lowest point on your boat. That lowest point could be your keel, props or rudder for example. Your tech may know what he means but the way he's telling you doesn't make sense.

The way you explain it make more sense....what i don't understand is that if my depth finder says 2 feet,
That would be how much water there is between the bottom of my keel to the water bed???
if so??

THEN I UNDERSTAND :smt038:smt038
 

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