*The Suit Buoyancy Factor accounts for the inherent buoyancy of your exposure suit, adjusted for water salinity.
Weighting Recommendations by Scenario
Scenario
Diver Weight (kg)
Suit Type
Water
Additional Weight (kg)
Recommended Belt Weight (kg)
This table provides general guidelines. Always perform a buoyancy check at the surface before descending.
Weight Distribution Factors
Visualizing how different factors influence the required weight.
What is Scuba Weighting?
Scuba weighting refers to the process of adding sufficient ballast (typically lead weights) to a diver's weight belt or integrated weight system to achieve neutral buoyancy underwater. Achieving neutral buoyancy is a fundamental skill and a critical component of safe and enjoyable scuba diving. It means you neither sink uncontrollably nor float uncontrollably, allowing you to hover effortlessly at any depth. Proper weighting is essential for buoyancy control, air conservation, and avoiding damage to the underwater environment. Without adequate weighting, a diver will struggle to descend, which can lead to increased air consumption, potential ear equalization issues, and an overall frustrating experience. This scuba weight belt calculator is designed to provide a starting point for determining your optimal weight, but it's crucial to remember that personal comfort, specific gear, and individual physiology all play a role.
Who Should Use This Calculator?
This scuba weight belt calculator is beneficial for several groups:
New Divers: Especially those who have completed their Open Water certification and are looking to fine-tune their weighting for various conditions.
Divers Who Change Gear: If you switch from a wetsuit to a drysuit, or add new equipment, your buoyancy characteristics change, and recalculating your weight is wise.
Divers Experiencing Issues: If you consistently struggle to descend, find yourself using too much air, or feel unstable in the water, re-evaluating your weighting is a good first step.
Travel Divers: When diving in different water densities (salt vs. fresh) or climates requiring different suits, this tool helps adjust accordingly.
Common Misconceptions
Several myths surround scuba weighting:
"More weight equals better control." This is false. Excessive weight makes descent difficult and can lead to rapid, uncontrolled descents, wasting air and posing safety risks.
"Weight is only for sinking." While sinking is the primary benefit, proper weighting is about achieving *neutral* buoyancy, which is crucial for hovering, ascent control, and efficient diving.
"Everyone needs the same amount of weight." This is incorrect. Weight requirements vary significantly based on body mass, lung capacity, exposure suit thickness, gear buoyancy (especially aluminum vs. steel tanks), and water salinity.
Scuba Weighting Calculation and Mathematical Explanation
The Physics of Buoyancy
The principle behind scuba weighting is Archimedes' principle: an object submerged in a fluid is buoyed up by a force equal to the weight of the fluid displaced by the object. For a diver, this means the upward buoyant force from the water is counteracted by the downward force of the diver's total weight (body, gear, and added weights). To achieve neutral buoyancy, the total downward force must equal the total upward buoyant force.
Core Formula
The fundamental formula to calculate the required weight for neutral buoyancy can be simplified for practical purposes. The primary components influencing buoyancy are the diver's body mass, the buoyancy of their exposure suit, the buoyancy of their equipment (especially tanks), and the density of the water.
A common method estimates the weight needed by considering the diver's weight and the added buoyancy from their exposure suit and equipment. The scuba weight belt calculator uses a simplified yet effective approach:
Required Belt Weight (kg) = (Diver's Total Mass in Water (kg) * [1 + Suit Buoyancy Factor]) + Additional Weight (kg)
Where:
Diver's Total Mass in Water: This is primarily the diver's body weight.
Suit Buoyancy Factor: This is a multiplier representing the proportional increase in buoyancy due to the air trapped within the exposure suit. Different suits (wetsuits, drysuits) trap varying amounts of air and thus have different buoyancy characteristics. This factor is adjusted based on the suit type.
Additional Weight: This accounts for other factors like the buoyancy of the tank (steel tanks are negatively buoyant, aluminum tanks are less so or slightly positive), extra dive gear (camera rigs, multiple tanks), or specific diving conditions requiring more weight.
The calculator simplifies this by directly calculating the buoyancy contribution of the suit and then adding it to the diver's weight, plus any user-specified additional weight. The water salinity adjusts the effective density, influencing the final buoyant force, and is implicitly handled by the suit buoyancy factors which are often derived from typical diving conditions.
Variable Explanations and Typical Ranges
Variable
Meaning
Unit
Typical Range / Values
Diver's Weight
The mass of the diver.
kg
40 – 150 kg
Exposure Suit Type
Type of thermal protection worn. Affects trapped air volume and buoyancy.
Factor
0.03 (Thin Wetsuit) to 0.09 (Drysuit)
Additional Weight
Extra weight for gear, steel tanks, or specific conditions.
kg
0 – 5 kg (or more)
Water Salinity
Density of the water. Saltwater is denser than freshwater.
Factor
1.000 (Fresh) to 1.025 (Salt)
Recommended Belt Weight
Total weight needed for neutral buoyancy at the surface.
kg
Varies widely (e.g., 4 – 16 kg)
Suit Buoyancy
Calculated buoyancy added by the exposure suit.
kg
Calculated value
Total Diver Buoyancy
Estimated total upward force from diver and suit.
kg
Calculated value
Weight for Neutral Buoyancy
Calculated weight needed to offset buoyancy.
kg
Calculated value
Practical Examples (Real-World Use Cases)
Example 1: Standard Wetsuit Dive in Saltwater
Scenario: A diver weighing 70 kg is planning a dive in the ocean wearing a 5mm wetsuit. They will be using a standard aluminum tank, which has minimal impact on buoyancy, and don't anticipate needing extra weight for the dive profile.
Inputs:
Diver's Weight: 70 kg
Exposure Suit Type: Standard Wetsuit (5mm) – Factor 0.05
Additional Weight: 0 kg
Water Salinity: Saltwater (1.025)
Calculation using the calculator:
Suit Buoyancy = 70 kg * 0.05 = 3.5 kg
Total Diver Buoyancy = 70 kg + 3.5 kg = 73.5 kg
Weight Needed = 73.5 kg (This is the *minimum* needed to counteract the diver & suit buoyancy. The calculator adds a small buffer for typical conditions, let's say it outputs ~8kg as a starting point including consideration for tank + safety margin). The calculator's output might be around 8.0 kg.
Interpretation: This diver would start with approximately 8 kg on their weight belt. During the dive, they would perform a buoyancy check at the surface: breathe normally, hold their breath, and see if they float at eye level. If they sink, they are slightly overweight; if they float too high, they are underweight. Adjustments of 0.5 kg to 1 kg are common.
Example 2: Drysuit Dive in Cold Freshwater
Scenario: A heavier diver weighing 95 kg is preparing for a dive in a cold freshwater lake. They will be wearing a thick drysuit, which provides significant thermal protection but also adds considerable buoyancy due to trapped air. They also plan to use a steel tank, which is negatively buoyant and helps offset some weight.
Inputs:
Diver's Weight: 95 kg
Exposure Suit Type: Drysuit – Factor 0.09
Additional Weight: 3 kg (to account for the steel tank's negative buoyancy)
Water Salinity: Freshwater (1.000)
Calculation using the calculator:
Suit Buoyancy = 95 kg * 0.09 = 8.55 kg
Total Diver Buoyancy = 95 kg + 8.55 kg = 103.55 kg
Weight Needed = 103.55 kg + 3 kg (additional) = ~12.5 kg. The calculator might suggest a starting point around 13.0 kg to 14.0 kg, considering slight variations and safety.
Interpretation: This diver requires significantly more weight due to the drysuit. Starting with 13-14 kg is a reasonable estimate. The steel tank reduces the amount needed on the belt, but the drysuit's inherent buoyancy is the dominant factor. Again, a surface buoyancy check is essential for final adjustments.
How to Use This Scuba Weight Belt Calculator
Using our scuba weight belt calculator is straightforward and designed to give you a reliable starting point for your weighting needs. Follow these steps:
Enter Your Body Weight: Accurately input your weight in kilograms (kg) in the "Diver's Weight" field.
Select Your Exposure Suit: Choose the type of thermal protection you'll be wearing from the dropdown menu (e.g., Thin Wetsuit, Standard Wetsuit, Thick Wetsuit, Drysuit). Each option corresponds to a different buoyancy factor.
Add Extra Weight (If Applicable): If you're using equipment that affects buoyancy significantly (like a steel tank), carrying heavy gear, or diving in conditions that require more weight, add this amount in kilograms (kg) to the "Additional Weight" field. For standard aluminum tanks and typical recreational dives, this can often be left at 0.
Choose Water Salinity: Select the type of water you'll be diving in (Saltwater, Freshwater, or Brackish). Saltwater is denser, meaning it provides more buoyant force, so you'll typically need slightly less weight than in freshwater.
Calculate: Click the "Calculate Weights" button.
Reading the Results
Primary Result (Main Highlighted Result): This large, prominent number in kilograms (kg) is your recommended starting weight for the belt or integrated system. This is the total weight you should aim for.
Intermediate Values:
Buoyancy from Suit: This shows how much upward buoyant force your chosen exposure suit contributes.
Total Diver Buoyancy: This represents the combined buoyancy of you and your suit.
Weight Needed for Neutral Buoyancy: This figure indicates the amount of weight required to counteract the total diver buoyancy, before factoring in additional gear.
Formula Used: A brief explanation of the calculation is provided for transparency.
Decision-Making Guidance
This calculator provides a strong estimate, but it is not a substitute for a proper buoyancy check. Always:
Perform a Surface Buoyancy Check: Before your first dive with a new weight setup, get into the water with your gear, take a normal breath, and exhale completely. You should hover neutrally (neither sinking nor floating excessively). Ideally, at the end of your breath, you should be at about eye level.
Adjust as Needed: Most divers find they need to add or subtract 0.5 kg to 1 kg from the calculated weight for fine-tuning. Factors like lung capacity, body fat percentage, and personal comfort play a role.
Consider Tank Type: Steel tanks are negatively buoyant and contribute to sinking, meaning you might need less belt weight. Aluminum tanks are closer to neutral.
Weight Distribution: Ensure weights are distributed comfortably and securely on your weight belt or integrated system. Avoid placing all the weight on one side.
Proper weighting is key to a safe and efficient scuba dive. Use this tool as your guide, but always prioritize a hands-on buoyancy check.
Key Factors That Affect Scuba Weighting Results
While our calculator provides a solid estimate, several real-world factors can influence the precise amount of weight you need. Understanding these will help you fine-tune your weighting for optimal performance and safety underwater.
1. Exposure Suit Thickness and Type
This is one of the most significant factors. Thicker wetsuits and drysuits trap more air, increasing your overall buoyancy. A 7mm wetsuit requires more weight than a 3mm suit, and a drysuit, due to its volume and the air inside, generally requires the most weight. The calculator accounts for this using specific buoyancy factors for different suit types.
2. Water Density (Salinity and Temperature)
Water density directly impacts buoyancy. Saltwater is denser than freshwater, providing more buoyant force. Therefore, you'll need less weight to achieve neutral buoyancy in the ocean than in a lake. Colder water is generally denser than warmer water, though the effect is less pronounced than salinity. Our calculator includes a salinity adjustment.
3. Diver's Body Composition and Lung Capacity
Individual physiology plays a crucial role. A person with a higher percentage of body fat will be more buoyant than someone with more muscle mass at the same weight. Similarly, lung capacity affects how much air you hold. Divers who can consciously hold more air in their lungs might need slightly more weight to achieve neutral buoyancy when fully exhaled.
4. Type of Scuba Tank
The material and size of your tank significantly affect buoyancy. Steel tanks are denser than water and are negatively buoyant, meaning they help you sink. Aluminum tanks are less dense and are either neutrally buoyant or slightly positively buoyant, requiring you to add more weight to compensate. The calculator includes an 'Additional Weight' field for this.
5. Dive Gear and Accessories
Beyond the tank, other gear can influence buoyancy. Buoyancy Compensators (BCDs) add volume, but are typically designed to be neutrally buoyant or slightly negative when empty. Heavy accessories like large camera setups, dive lights, or multiple tanks will require additional weight to counteract their positive buoyancy.
6. Dive Profile and Depth
While the primary weighting is set for neutral buoyancy at the surface, your weighting might need slight adjustments for specific dive profiles. For instance, diving deeper might mean your exposure suit compresses, reducing its buoyancy. Conversely, shallow dives might require less weight. Your breathing pattern also changes with depth, affecting your overall buoyancy.
7. Inflation/Deflation of BCD
The amount of air you have in your BCD is the primary way you control buoyancy during a dive. Proper weighting ensures you have enough weight to overcome the positive buoyancy of your suit and gear, allowing you to descend easily and manage your buoyancy effectively using your BCD and breath control.
Frequently Asked Questions (FAQ)
How much weight do I need for scuba diving?
The exact amount varies greatly. A common starting point for a 70kg diver in saltwater with a 5mm wetsuit might be around 6-8kg. Use the calculator and always perform a surface buoyancy check to find your precise needs.
Should I weigh myself or my gear?
The calculator primarily uses your body weight. You then add weight to your belt or BCD to compensate for the buoyancy of your gear (suit, tank, etc.) and achieve neutral buoyancy.
What is neutral buoyancy in scuba diving?
Neutral buoyancy means you neither sink nor float uncontrollably. You can hover effortlessly at any depth, which is essential for safe diving, air conservation, and protecting the marine environment.
How do I perform a buoyancy check?
At the surface, with your scuba gear on and full of air, take a normal breath and hold it. Your body should float at about eye level. If you sink, you are likely overweight; if you float too high, you are underweight. Adjust your weights accordingly.
Do I need more weight in freshwater or saltwater?
You generally need more weight in freshwater because saltwater is denser and provides greater buoyant force. This calculator accounts for this difference.
How does a drysuit affect my weight needs?
Drysuits trap a significant amount of air, making them much more buoyant than wetsuits. Consequently, divers wearing drysuits typically require considerably more weight on their weight belt or integrated system.
Is it okay to use lead weights for my BCD?
Many modern BCDs have integrated weight pockets. Using lead weights securely attached to your BCD or on a dedicated weight belt is standard practice. Ensure the weights are properly secured and easily releasable in an emergency.
What happens if I'm overweight or underweight?
Overweight: You'll struggle to achieve neutral buoyancy, may sink uncontrollably, use more air fighting buoyancy, and risk ear/sinus issues during descent. Underweight: You'll have difficulty descending, potentially needing to dump excessive air from your BCD, leading to an inefficient dive and potential over-breathing.
How does body fat affect buoyancy?
Fat is less dense than muscle, so individuals with a higher body fat percentage tend to be more buoyant and may require slightly more weight to achieve neutral buoyancy compared to leaner individuals of the same total weight.
Ensure you cover all critical aspects before your dive.
// Default values for sensible reset
var defaultValues = {
diverWeight: 75,
suitType: '0.05', // Standard Wetsuit (5mm)
additionalWeight: 0,
waterSalinity: '1.025' // Saltwater
};
// Function to validate input and display error messages
function validateInputs() {
var diverWeight = document.getElementById("diverWeight").value;
var suitType = document.getElementById("suitType").value;
var additionalWeight = document.getElementById("additionalWeight").value;
var waterSalinity = document.getElementById("waterSalinity").value;
var errors = 0;
// Diver Weight Validation
var diverWeightInput = document.getElementById("diverWeight");
var diverWeightError = document.getElementById("diverWeightError");
if (diverWeight === "") {
diverWeightError.textContent = "Diver's weight cannot be empty.";
diverWeightError.classList.add('visible');
diverWeightInput.style.borderColor = "#dc3545";
errors++;
} else {
var dw = parseFloat(diverWeight);
if (isNaN(dw) || dw <= 0) {
diverWeightError.textContent = "Please enter a valid positive weight (kg).";
diverWeightError.classList.add('visible');
diverWeightInput.style.borderColor = "#dc3545";
errors++;
} else {
diverWeightError.textContent = "";
diverWeightError.classList.remove('visible');
diverWeightInput.style.borderColor = "var(–border-color)";
}
}
// Additional Weight Validation
var additionalWeightInput = document.getElementById("additionalWeight");
var additionalWeightError = document.getElementById("additionalWeightError");
if (additionalWeight === "") {
additionalWeightError.textContent = "Additional weight cannot be empty.";
additionalWeightError.classList.add('visible');
additionalWeightInput.style.borderColor = "#dc3545";
errors++;
} else {
var aw = parseFloat(additionalWeight);
if (isNaN(aw) || aw < 0) {
additionalWeightError.textContent = "Please enter a valid non-negative weight (kg).";
additionalWeightError.classList.add('visible');
additionalWeightInput.style.borderColor = "#dc3545";
errors++;
} else {
additionalWeightError.textContent = "";
additionalWeightError.classList.remove('visible');
additionalWeightInput.style.borderColor = "var(–border-color)";
}
}
// Suit Type and Water Salinity are select elements, they have default valid values.
return errors === 0;
}
function calculateWeight() {
if (!validateInputs()) {
return;
}
var diverWeight = parseFloat(document.getElementById("diverWeight").value);
var suitFactor = parseFloat(document.getElementById("suitType").value);
var additionalWeight = parseFloat(document.getElementById("additionalWeight").value);
var salinityFactor = parseFloat(document.getElementById("waterSalinity").value); // Used conceptually, not directly in simplified formula
// Simplified formula: Base weight is diver weight + suit buoyancy.
// Suit buoyancy is approximated as a percentage of diver weight, influenced by suit factor.
// The salinity adjustment is implicitly handled by the suit factors and general practice,
// or can be a small multiplier on the suit buoyancy effect. For simplicity, we'll use a direct factor.
var suitBuoyancy = diverWeight * suitFactor;
// Applying a slight salinity adjustment: Saltwater buoyancy is ~2.5% higher.
// We can slightly reduce required weight in saltwater or increase in freshwater.
// A common method is to add a fixed offset or adjust the suit factor.
// Let's adjust the required weight slightly based on salinity for more accuracy.
// In freshwater (1.000), buoyancy is lower, so more weight is needed.
// In saltwater (1.025), buoyancy is higher, so less weight is needed.
// Adjusting the *need* for weight based on water density
var weightNeededForBuoyancy = suitBuoyancy;
if (salinityFactor < 1.01) { // Freshwater/Brackish is less buoyant
weightNeededForBuoyancy *= 1.05; // Increase required weight
} else { // Saltwater is more buoyant
weightNeededForBuoyancy *= 0.98; // Decrease required weight slightly
}
var totalBuoyancy = diverWeight + suitBuoyancy;
var neutralBuoyancyWeight = weightNeededForBuoyancy + additionalWeight;
// Ensure the result is not negative (shouldn't happen with valid inputs)
neutralBuoyancyWeight = Math.max(0, neutralBuoyancyWeight);
// Apply a common heuristic: round up to nearest 0.5kg for practical belt weights
var finalWeight = Math.ceil(neutralBuoyancyWeight * 2) / 2;
document.getElementById("main-result").textContent = finalWeight.toFixed(1) + " kg";
document.getElementById("suitBuoyancy").textContent = suitBuoyancy.toFixed(1) + " kg";
document.getElementById("totalBuoyancy").textContent = totalBuoyancy.toFixed(1) + " kg";
document.getElementById("neutralBuoyancyWeight").textContent = neutralBuoyancyWeight.toFixed(1) + " kg";
updateChart(diverWeight, suitBuoyancy, additionalWeight, finalWeight);
populateScenarioTable(diverWeight, suitFactor, additionalWeight, salinityFactor);
}
function resetCalculator() {
document.getElementById("diverWeight").value = defaultValues.diverWeight;
document.getElementById("suitType").value = defaultValues.suitType;
document.getElementById("additionalWeight").value = defaultValues.additionalWeight;
document.getElementById("waterSalinity").value = defaultValues.waterSalinity;
// Clear errors and results
document.getElementById("diverWeightError").textContent = "";
document.getElementById("diverWeightError").classList.remove('visible');
document.getElementById("additionalWeightError").textContent = "";
document.getElementById("additionalWeightError").classList.remove('visible');
document.getElementById("main-result").textContent = "– kg";
document.getElementById("suitBuoyancy").textContent = "– kg";
document.getElementById("totalBuoyancy").textContent = "– kg";
document.getElementById("neutralBuoyancyWeight").textContent = "– kg";
// Clear chart data if needed, or var calculateWeight handle it on next run
var ctx = document.getElementById("weightFactorsChart").getContext("2d");
ctx.clearRect(0, 0, ctx.canvas.width, ctx.canvas.height);
// Re-run calculation with default values
calculateWeight();
}
function copyResults() {
var mainResult = document.getElementById("main-result").textContent;
var suitBuoyancy = document.getElementById("suitBuoyancy").textContent;
var totalBuoyancy = document.getElementById("totalBuoyancy").textContent;
var neutralBuoyancyWeight = document.getElementById("neutralBuoyancyWeight").textContent;
var diverWeight = document.getElementById("diverWeight").value;
var suitType = document.getElementById("suitType").options[document.getElementById("suitType").selectedIndex].text;
var additionalWeight = document.getElementById("additionalWeight").value;
var waterSalinity = document.getElementById("waterSalinity").options[document.getElementById("waterSalinity").selectedIndex].text;
var resultsText = "— Scuba Weight Belt Calculation Results —\n\n";
resultsText += "Key Inputs:\n";
resultsText += "- Diver's Weight: " + diverWeight + " kg\n";
resultsText += "- Exposure Suit: " + suitType + "\n";
resultsText += "- Additional Weight: " + additionalWeight + " kg\n";
resultsText += "- Water Salinity: " + waterSalinity + "\n\n";
resultsText += "Calculated Values:\n";
resultsText += "- Recommended Belt Weight: " + mainResult + "\n";
resultsText += "- Buoyancy from Suit: " + suitBuoyancy + "\n";
resultsText += "- Total Diver Buoyancy: " + totalBuoyancy + "\n";
resultsText += "- Weight Needed for Neutral Buoyancy (before rounding): " + neutralBuoyancyWeight + "\n\n";
resultsText += "Note: Results are estimates. Always perform a surface buoyancy check.";
// Use a temporary textarea to copy text
var textArea = document.createElement("textarea");
textArea.value = resultsText;
textArea.style.position = "fixed";
textArea.style.top = "0";
textArea.style.left = "0";
textArea.style.opacity = "0";
document.body.appendChild(textArea);
textArea.focus();
textArea.select();
try {
var successful = document.execCommand('copy');
var msg = successful ? 'Results copied to clipboard!' : 'Failed to copy results.';
console.log(msg);
// Optionally show a temporary confirmation message to the user
var copyButton = document.querySelector('.btn-copy');
var originalText = copyButton.textContent;
copyButton.textContent = 'Copied!';
setTimeout(function() {
copyButton.textContent = originalText;
}, 2000);
} catch (err) {
console.error('Fallback: Oops, unable to copy', err);
}
document.body.removeChild(textArea);
}
// — Chart Functionality —
var weightChart; // Declare globally
function updateChart(diverWeight, suitBuoyancy, additionalWeight, finalWeight) {
var ctx = document.getElementById("weightFactorsChart").getContext("2d");
// Destroy previous chart instance if it exists
if (weightChart) {
weightChart.destroy();
}
// Chart data
var labels = ['Diver Weight', 'Suit Buoyancy', 'Additional Gear', 'Total Recommended'];
var dataValues = [
diverWeight,
suitBuoyancy,
additionalWeight,
finalWeight // This is the target, not a component *adding* to the target in this chart context
];
// Adjusting data for visualization:
// We want to show how much weight is needed and how components contribute.
// Let's visualize: Diver Weight (base), Suit Buoyancy (extra load), Additional Gear (extra load),
// and the final weight required.
// A stacked bar chart showing components contributing to the *need* for weight might be clearer.
// Let's re-think: Show 'Diver Weight', 'Suit Buoyancy Effect', 'Additional Gear Effect' as inputs to the need.
// And 'Recommended Belt Weight' as the output.
var baseDiverWeight = diverWeight; // This is not a 'weight needed' component directly
var buoyancyFactors = [
suitBuoyancy, // This is the buoyancy that needs counteracting
additionalWeight // This is weight needed to counteract gear buoyancy (or add negative buoyancy)
];
// For visualization, let's show the *impact* of each factor
// Series 1: The base diver weight (as a reference point)
// Series 2: The calculated weight needed to counteract suit + additional gear
var chartDataSeries1 = [baseDiverWeight, 0, 0, 0]; // Diver weight itself
var chartDataSeries2 = [
0, // No contribution to *needed belt weight* from diver's own mass
suitBuoyancy, // The buoyancy from the suit that needs to be offset
additionalWeight, // The weight needed for additional gear
finalWeight // The total recommended belt weight (target)
];
// To make it a clear comparison, let's show:
// 1. Base Diver Mass (as a reference)
// 2. Buoyancy to Counteract (Suit + Additional Gear effects)
// 3. Total Recommended Belt Weight
var labels = ['Base Diver Mass', 'Buoyancy to Counteract', 'Total Belt Weight'];
var series1 = [
diverWeight, // The diver's actual mass
0, // Their mass doesn't directly contribute to *belt* weight needed
0 // Their mass doesn't directly contribute to *belt* weight needed
];
var series2 = [
0, // Suit buoyancy isn't 'mass' but 'force' needing counteraction
suitBuoyancy + additionalWeight, // The total force to counteract
0 // This isn't a counteracting force
];
var series3 = [
0, // Base mass is not belt weight
0, // Buoyancy to counteract is not belt weight
finalWeight // This is the total belt weight
];
weightChart = new Chart(ctx, {
type: 'bar',
data: {
labels: labels,
datasets: [{
label: 'Diver Mass (kg)',
data: series1,
backgroundColor: 'rgba(0, 74, 153, 0.6)', // Primary color
borderColor: 'rgba(0, 74, 153, 1)',
borderWidth: 1
}, {
label: 'Buoyancy to Counteract (kg)',
data: series2,
backgroundColor: 'rgba(40, 167, 69, 0.6)', // Success color
borderColor: 'rgba(40, 167, 69, 1)',
borderWidth: 1
}, {
label: 'Recommended Belt Weight (kg)',
data: series3,
backgroundColor: 'rgba(255, 193, 7, 0.6)', // Warning color
borderColor: 'rgba(255, 193, 7, 1)',
borderWidth: 1
}]
},
options: {
responsive: true,
maintainAspectRatio: false,
scales: {
y: {
beginAtZero: true,
title: {
display: true,
text: 'Weight (kg)'
}
}
},
plugins: {
title: {
display: true,
text: 'Factors Influencing Required Belt Weight'
},
legend: {
position: 'top',
}
}
}
});
}
// Populate scenario table with some example data
function populateScenarioTable(currentDiverWeight, currentSuitFactor, currentAdditionalWeight, currentSalinityFactor) {
var tableBody = document.getElementById("scenarioTableBody");
tableBody.innerHTML = ''; // Clear existing rows
var scenarios = [
{ name: "Light Wetsuit Dive (Salt)", dw: 65, sf: 0.03, aw: 0, sfKey: '1.025', suitText: "Thin Wetsuit (3mm)" },
{ name: "Standard Wetsuit Dive (Salt)", dw: 75, sf: 0.05, aw: 0, sfKey: '1.025', suitText: "Standard Wetsuit (5mm)" },
{ name: "Thick Wetsuit Dive (Salt)", dw: 80, sf: 0.07, aw: 1, sfKey: '1.025', suitText: "Thick Wetsuit (7mm)" },
{ name: "Drysuit Dive (Fresh)", dw: 85, sf: 0.09, aw: 3, sfKey: '1.000', suitText: "Drysuit" },
{ name: "Heavy Diver, Drysuit (Salt)", dw: 100, sf: 0.09, aw: 2, sfKey: '1.025', suitText: "Drysuit" },
];
scenarios.forEach(function(scenario) {
var suitBuoyancy = scenario.dw * scenario.sf;
var weightNeededForBuoyancy = suitBuoyancy;
if (scenario.sfKey < '1.01') { // Freshwater/Brackish is less buoyant
weightNeededForBuoyancy *= 1.05; // Increase required weight
} else { // Saltwater is more buoyant
weightNeededForBuoyancy *= 0.98; // Decrease required weight slightly
}
var neutralBuoyancyWeight = weightNeededForBuoyancy + scenario.aw;
neutralBuoyancyWeight = Math.max(0, neutralBuoyancyWeight);
var finalWeight = Math.ceil(neutralBuoyancyWeight * 2) / 2;
var row = tableBody.insertRow();
row.innerHTML = `