Raymarine LIGHTHOUSE 4, Operation Instructions Manual

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2. Maximum height from waterline
3. Waterline
4. [Minimum safe height]
Minimum safe height calculation guidance
The information below is provided for guidance only and is not exhaustive.
Some influencing factors can be unique to certain vessels and / or areas of
water and may not be listed below. You should ensure you account for ALL
factors that apply to your current situation when making calculations.
Some of the factors that can influence vessel height are shown below:
• Vessel displacement (weight) — A vessel’s height (from the waterline) will
decrease when it is fully laden compared with its unladen displacement.
• Water type — A vessel’s height will decrease by approximately 2% to 3% in
fresh water compared to seawater.
Some of the factors that should be taken into account when calculating
a safety margin are:
• Vessel maneuvering characteristics — A vessel’s height changes due
to squat, trim, roll, pitch and heave.
• Chart accuracy — The electronic chart data may not be accurate or may
have changed since the last survey.
• Weather conditions — Low air pressure, and prevailing wind strength
and direction can affect water level.
Minimum safe width
During the start up wizard you can set a minimum safe width for your vessel.
The minimum safe width can also be added or changed at anytime from the
[Boat details] setting menu: [Homescreen > Settings > Boat details] .
A suitable value for minimum safe width can be established by identifying
your vessel’s maximum width and adding a safety margin to each side.
• Maximum width — Taken from the widest point.
• Safety margin — An adequate clearance to either side of the vessel.)
1. Port safety margin
2. Maximum vessel width (beam)
3. Starboard safety margin
4. [Minimum safe width]
Minimum safe width calculation guidance
The information below is provided for guidance only and is not exhaustive.
Some influencing factors can be unique to certain vessels and / or areas of
water and may not be listed below. You should ensure you account for ALL
factors that apply to your current situation when making calculations.
Some of the factors that should be taken into account when calculating
a Safety Margin are:
• Vessel maneuvering characteristics — A vessel’s required clearance will
increase due to roll.
• Chart accuracy — The electronic chart data may not be accurate or may
have changed since last surveyed.
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