Self-Defense For Cruisers

Self-Defense for Cruisers

By: Ryan Levinson (Captain, SV Kiapa Nui)


This document is intended to serve as a starting point for thought and discussion rather than a source for reference and/or instruction about self-defense. Use the contents of this document at your own risk.


As an athlete, professional captain, and influencer, I periodically accept payment or equipment for promotional purposes. However, no compensation, monetary or otherwise, has been received for the content of this document. In the interest of full transparency, I should note that a company named "Byrna" provided some of their products for me to assess with regards to cruiser self-defense. This was done at my request and without any expectation of endorsement.

Byrna manufactures devices that propel "projectiles" using CO2 technology, similar to that used in paintball guns. While some paintball gun manufacturers offer modified versions of their products for self-defense, Byrna is the first to produce such a device specifically for this purpose. The differences in technology and application between these two categories of products are significant, leading me to refer to the Byrna devices as "Byrnas" within this document. Much like "Velcro" has become the colloquial term for "hook and loop" fasteners, "Byrna" is often used to describe this specific type of self-defense device.

Furthermore, Byrna has taken the initiative to cater to the unique needs of cruisers. While this decision, undeniably, has a commercial incentive, it offers an invaluable benefit to the cruising community by supplying a self-defense solution well suited to our needs and by facilitating direct communication. To endorse this initiative, I voluntarily participated in a Byrna-produced video message and served as a guest on their podcast, doing so without receiving any form of compensation.


A common misconception is that the most frequent self-defense situations cruisers face involve life-or-death scenarios, such as encounters with armed aggressors like pirates or violent criminals. While severe, such situations are extremely rare.

The most common self-defense threats cruisers face include, in no particular order - 'petty' property theft by unarmed criminals, non-lethal physical assault (including rape), and attacks from animals. Despite this reality, most discussions related to cruiser self-defense revolve around firearms and/or dubious alternatives to firearms, such as modified flare guns, spears, etc., or deterrents like chemical sprays, security "bars," locks, etc.

Much like we all prepare for abandoning ship, crew overboard, fire suppression, etc., preparing for self-defense can enhance our sense of freedom and enjoyment while cruising by offering a greater peace of mind. In other words, be prepared, not paranoid.

Objective of Self-Defense:

To protect oneself, one's property, or another person from physical harm or the threat of harm by undertaking reasonable and necessary actions, including force if required.

General Considerations:

Levels Of Threat:


Level 5 - No Detectable Threat 

Level 4 - Potential Threat in Visual Range

Level 3 - Potential Threat in Auditory Range

Level 2 - Potential Threat Attempting to Board Or Is Onboard Vessel

Level 1 - Potential Threat Is Inside Cabin And/Or Within 10’ of Person



LEVEL 5 - No Detectable Threat

Avoid being a tempting, easy target. Most self-defense threats involve opportunistic “petty” theft of dinghies and/or valuable items left unguarded on deck or in plain view in the cabin.  This means the vast majority of theft can be prevented simply by taking actions like raising your dinghy at night and stowing valuable gear.  

Develop positive community relations and foster good will with locals and other cruisers. “Know where you go” to avoid areas known to have increased levels of threat. Be aware of how the local threats most commonly manifest. Remain informed about any changes to the safety situation in the area(s) you plan to visit.



LEVEL 4 - Potential Threat in Visual Range

Detect, assess, and contact (e.g., via spotlight) potential threats as early as possible. Assume an increasingly defensive posture if potential threat continues to approach but do not act provocatively or take action that may escalate the situation unless you’re certain the threat is real. Notify additional resources if appropriate (e.g., other cruisers, authorities, additional crew, etc) as early as possible.  At this level, potential threats are out of effective range of most common firearms and launchers.



LEVEL 3 - Potential Threat in Auditory Range

The same general considerations as Level 4 apply, except now it is possible to communicate, conduct a more thorough threat assessment, and/or provide directives as deterrence. Potential threats are now in effective range of most firearms and some Byrna launchers*.

IMPORTANT: As increasingly aggressive defensive options are considered, it becomes increasingly critical to conduct an accurate assessment of the threat. Defensive response must be proportionate to the actual threat, not the potential or imagined threat, nor level of fear. IF THE THREAT IS NOT CLEAR, AVOID USING AGGRESSIVE ACTIONS THAT COULD BE MISINTERPRETED BY THE APPROACHING PERSON(S).



LEVEL 2 - Potential Threat Attempting To Board or Already On Deck

While the potential for threat is much higher than levels 3-5, it is still not a certainty, so accurate assessment is still critical. We know of many situations where a boat was boarded by a stranger who was attempting to return a drifting dinghy, leaving gifts of fruit or fish, hoping to make friendly contact but unaware of proper etiquette, etc.

That said, the consequences of not identifying and responding to a threat at this stage are much higher, so more aggressive response(s) may be appropriate. It is important to maintain composure and clear thinking when assessing the situation and deciding on the appropriate response. Panicking or acting impulsively can lead to unnecessary conflict or harm.

Potential threats are now within range of all firearms, launchers, and some chemical sprays such as pepper spray or mace, but A POTENTIAL THREAT CANNOT LEAVE THE BOAT IF HE/SHE IS TEMPORARILY INCAPACITATED BY A CHEMICAL IRRITANT! Be aware that chemical irritants can cause severe disorientation and difficulty breathing which may lead to an increased risk of drowning if the person were to fall in the water.

Remember, at this level, you can't run away to escape an incapacitated threat so deterring one with kinetic projectiles and/or other non-chemical measures may be preferable if they are available and proving effective.


   •    Verbal challenge

   •    Loud sounds (e.g., sirens, whistles, horns)

   •    Spotlight in eyes

   •    Strobe light

   •    High Pressure Water

   •    Byrna launcher firing kinetic projectiles 

   •    Live rounds from firearm (CAUTION - see ‘Considerations Regarding Firearms’ below)*


   •    Motion detectors

   •    Cameras

   •    Pressure sensor mats

   •    “Tripwire” alarms

   •    Thumbtacks, jacks, stacks of empty cans, etc. on deck

   •    Visual watch

   •    Listen for footsteps, objects impacting the hull, etc.

   •    Look for light from flashlights, silhouettes in the moonlight/star scape, etc. 

   •    “Community” watch with nearby boats

   •    Dog

LEVEL 1 - Potential Threat Is Inside Cabin And/Or Within 10’ of Person

Regardless of the presence of a weapon, this situation is potentially the most critical. Although the threat may be perceived rather than real, the consequences of a mistaken assessment could be dire. Act decisively, but remember that your actions will be judged by how proportionate they were to the actual threat. You might face legal or other repercussions if, for example, you deploy a taser against an unarmed person trying to steal a dive mask from your deck when there was a lower threat of bodily harm.

Prevent anyone from grabbing you, even if it requires using items like chemical irritants or a taser. Remember, A THREAT CANNOT LEAVE THE BOAT IF HE/SHE IS TEMPORARILY INCAPACITATED BY A CHEMICAL IRRITANT OR TASER SHOCK, and at this level, you are at a higher risk being affected by chemicals you deploy. Be aware that chemical irritants can cause severe disorientation and difficulty breathing, and a taser can incapacitate muscles, which may lead to an increased risk of drowning if the person were to fall in the water.

Ensure any weapon(s) you have are not taken and used against you. Foster a calm, clear, yet aggressive mindset through regular training and the other preparations mentioned below


   •    Verbal challenge

   •    Loud sounds (e.g., sirens, whistles, horns)

   •    Spotlight in eyes

   •    Strobe light

   •    Byrna launcher firing kinetic or chemical projectiles 

   •    Chemical irritants 

   •    Taser

   •    Boat hook, baseball bat, and/or other similar weapon

   •    Cans of food, bottles of wine, or other common objects that can be thrown

   •    Robust means of securing doors and hatches

   •    Live rounds from firearm (CAUTION - see ‘Considerations Regarding Firearms below’)*


   •    Motion detectors

   •    Cameras

   •    Pressure sensor mats

   •    “Tripwire” alarms

   •    Alarms on doors and hatches

   •    Thumbtacks, jacks, stacks of empty cans, etc. on deck

   •    Visual watch

   •    Listen for footsteps, etc.

   •    Look for light from flashlights, silhouette(s) in the moonlight/star scape, etc. 

   •    Dog

LEVEL 0 - Threat Actualized as Harm

This level may be immediately reached from any prior level if the threat is armed with a long-range weapon. 

At Level 0, when harm has been actualized, you must assume you're fighting for your life and act accordingly. However, remember that you may still be held to the standard of proportionate response and other legal considerations. Determine beforehand what level of risk you're willing to take if the alternative is death or severe bodily harm through personal contemplation, scenario analysis, and training. Do not let your ego provoke a disproportionate response. It is crucial to maintain a calm, clear, yet aggressive mindset, and ensure any weapon you deploy is not used against you.


Avoid presenting a Byrna launcher, firearm, or other weapon with the sole intention of deterring a potential threat by having them believe you are armed.  There may be situations where this is an effective tactic, but there are significant risks involved, including potentially escalating the situation into a firefight, or provoking an unfavorable response from the local population and/or law enforcement. USE THE LEAST AGGRESSIVE MEANS NECESSARY T0 0BTAIN THE DESIRED OUTCOME. 

Real World Examples:

The most common scenarios we experienced personally or learned about from firsthand accounts involve the theft of dinghies, outboards, equipment left on deck, or valuables inside the cabin while the cruisers were asleep or distracted (e.g., playing in the water, visiting another boat, etc.).

The next most common scenarios involve physical assault, usually by a local inhabitant who is upset with the cruiser, sometimes for nothing more than the fact that the cruiser is a foreigner. Some of these assaults includes rape, where the victims were assaulted randomly when the opportunity presented itself rather than in a premeditated manner. Alcohol, other drugs, and mental illness are common contributing factors. Other scenarios involve attacks from animals, usually dogs, but also sometimes animals like monkeys and wild boars.

Here is a short list of scenarios we personally faced or learned about from firsthand accounts. What would you do in these situations?  What could have been done to prevent them or to be better prepared to manage them?  The actual outcomes are listed below…

The Actual Outcomes:

Effective Self Defense Preparation Includes:

After-Action Considerations:

Launcher and Firearm Safety:

Even if you have familiarity with firearms and launchers, it is important to receive formal training in the safe handling and effective operation of firearms for self-defense. Additionally, regular practice and ongoing training is essential to maintain proficiency.

There is a lot of important information regarding firearm and launcher safety, but here are some universally accepted guidelines:

The 4 Universal Rules of Firearm and Launcher Safety:

*Considerations Regarding Having Guns While Cruising:

I am not an expert on firearms. The following considerations are just my opinions and may or may not be accurate. You must do your own research and soul-searching while deciding whether or not to bring a firearm with you while cruising.

Considerations For Self Defense Equipment Used By Cruisers:

The best self-defense tools are the ones that you're comfortable using, that you're trained to use, and that are legally and practically suitable for your situation. Other considerations for self-defense equipment used by cruisers include:

    •    Durability in a maritime environment

    •    Ease of use

    •    Ability to regularly practice or train with the equipment to maintain proficiency

    •    Ease of restock/repair

    •    Ability to stow securely yet still deploy quickly

    •    The repercussions when it is seen by local inhabitants and/or other cruisers

    •    The legal implications in the area(s) you will be cruising

    •    Cost, weight, size, and other considerations universal for equipment on boats

    •    How its use will be affected by factors such as wind, rain, moving deck, etc.

Remember that deploying a firearm, or anything that may be mistaken for a firearm, may provoke a strong unintended response, including potentially provoking a firefight.

Before deciding on any self-defense tool, it's crucial to research and understand the laws and regulations in your cruising destinations. Failure to comply with local laws can lead to severe penalties, including imprisonment. Consider seeking advice from local authorities, legal experts, or other experienced cruisers to ensure you're making an informed decision.

There's a substantial amount of mythology surrounding the use of items like flare guns and spear guns for self-defense. It's crucial to separate fact from fiction, so if possible, conduct your own 'real world' testing with these items before deciding to depend on them in a self-defense situation. The results may surprise you. As a general rule, you're likely to be much safer and more effectively protected when using equipment and techniques that are purpose-built for self-defense

Spearguns in particular may not be the best choice for self-defense unless you’re in the water. They are slow to load, single-shot, and challenging to aim accurately, particularly when not underwater. They also present a high risk of rebound injury, either from the spear retracting along the shot line or from band malfunction.

Furthermore, spearguns cannot be left in a 'ready' state for extended periods. Intended as lethal weapons, spearguns should only be considered when your life is in immediate danger, there's only one aggressor at relatively close range, and you're prepared to use lethal force - but only if you're confident of not missing with your single shot.

With spearguns there is a relatively high potential for accidental discharge, dangerous escalation, and equipment malfunction. Given these limitations, there are other more reliable and effective options for self-defense.

Byrna launchers are NOT intended to be an alternative or replacement for firearms. The launchers are a unique tool in a complete self-defense inventory as they are a less-lethal weapon that can be deployed effectively at a variety of ranges and with deterrence options ranging from the pain of being hit by kinetic projectiles, to temporary incapacitation resulting from exposure to tear gas or pepper projectiles.

Byrna launchers have similar form factor and basic function as common firearms. Therefore, when you are in a situation where using firearms is impractical or illegal, the launchers can be used to help maintain proficiency in aspects like weapon manipulation, defensive movements, sighting, and in operating optics, lights and lasers, etc.

Byrna launchers are cost effective, easy to stow, and constructed of materials well suited for maritime environments. They have a proven record of effective use by law enforcement agencies and private citizens. In my opinion they are one of the most effective less-lethal option available to prevent a potential threat from approaching and/or boarding your vessel, and against threats such as aggressive dogs and/or hostile people on land.

Finally, if a potential threat is already onboard your vessel, a Byrna launcher provides you with the ability to deploy kinetic and/or chemical deterrents from a safer distance than most other self-defense options.

Chemical sprays (e.g., pepper spray and mace) are effective at incapacitating an aggressor at relatively close ranges. They are designed primarily for situations where you can personally escape the situation after the chemical has been deployed, something that is often not possible when the aggressor is onboard your boat with you.

Note that chemical sprays are less effective and/or or potentially dangerous for you to use in situations where wind is present, especially if the wind is variable or blowing towards you as you deploy the spray.

Remember, with all self-defense tools, training and proficiency are key to help ensure you're able to use them effectively in a high-stress situation. Additionally, understanding the laws and regulations in your cruising destinations is crucial. Some jurisdictions may have restrictions on the possession or use of these items, and failure to comply can sometimes lead to severe penalties.

Partial List of Suggested Less-Lethal Equipment for Cruiser Self-Defense:

It's crucial that anyone using and/or carrying this equipment is well-trained in their safe and efficient deployment. An untrained individual, or an individual who does not maintain proficiency, could pose a risk to themselves and others if they attempt to use a self-defense tool in a high-stress situation. Regular training and practice are necessary to maintain proficiency and ensure the safe and effective use of self-defense tools.

For More Information: