Pontoon Float Draft - V4

Pontoon Float or Boat Draft Calculation This calculator assumes that a pontoon float or boat consists of two or more pontoons tied together by some form of structure, which is decked over to form a platform for people and gear.

Assumptions: Dpontoon  27in

Diameter of the pontoon

Lpontoon  48ft

Length of the pontoon

Npontoon  2

Total number of pontoons

γpontoon  54.07

lbf

DLstruct  2747lbf γwater  62.4

lbf ft

3

Unit weight of the pontoon

ft Weight of platform, hardware, etc. Unit Weight of water Fresh: 62.4 Salt: 64

Calculations: DLvessel  γpontoon Lpontoon  Npontoon  DLstruct DLvessel  7937.72 lbf

Total weight of the pontoon boat (unloaded)

2

 Dpontoon  Vpontoon  π    Npontoon Lpontoon 2  

GLvessel 

 Vpontoon γwater  DLvessel 2

GLvessel  7940.29 lbf

Calculate the total volume of the pontoons

Calculate the Recommended Maximum Gross Load per: "Construction Standards for Small Vessels (2010)" TP 1332 E - Section 4

Recommended Maximum Gross Load - Passengers & Gear

DLvessel

Volume of water displaced by just the pontoon boat weight

DLVol  127.21 ft

3

Volume of water displaced by pontoon boat + peaple + gear

GLVol  254.46 ft

3

DLVol DLArea  Npontoon Lpontoon

End area of submerged pontoon, pontoon boat weight

DLArea  1.33 ft

2

GLVol GLArea  Npontoon Lpontoon

End area of submerged pontoon, pontoon boat weight + peaple + gear

GLArea  2.65 ft

2

DLVol 

GLVol 

γwater DLvessel  GLvessel γwater

In this next section, we need to use calculated values to pick values from a table. Table is attached at the end of this worksheet. DLArea

inTableDL 

Dpontoon

2

GLArea

inTableLL 

Dpontoon

2

inTableDL  0.26

Find this number in the table, under the column area/D 2. Pick the value of d/D from the column to the left of your value, and enter it below.

inTableLL  0.52

Find this number in the table, under the column area/D 2. Pick the value of d/D from the column to the left of your value, and enter it below.

outTableDL  0.37

This is the number you picked off the table, in the d/D column and from the same row as the value for inTable DL

outTableLL  0.63

This is the number you picked off the table, in the d/D column and from the same row as the value for inTable LL

d DL  outTableDL Dpontoon

d LL  outTableLL Dpontoon

Multiply the value found above by the pontoon diameter to find the submerged depth or draft of the pontoon boat under just it's own weight.

Multiply the value found above by the pontoon diameter to find the submerged depth or draft of the pontoon boat under just it's own weight.

Results: d DL  9.99 in

Submerged depth or draft of the pontoon boat under just it's own weight.

d LL  17.01  in Submerged depth or draft of the pontoon boat with passengers and gear.