Mounting A Depth Finder: Aluminum Boat Installation Guide

Installing a depth finder on an aluminium boat is a valuable addition to any boat. It provides crucial information about the water depth beneath the vessel, aiding navigation and ensuring safe passage. There are two common installation methods for depth finders: through-hull and transom mount. The choice between the two methods depends on your boat's design, preferences, and requirements. Consider factors such as ease of installation, accuracy, and potential interference when selecting the installation method.

For through-hull installation, carefully drill a hole in the boat's hull at the chosen location, following the manufacturer's guidelines. Apply sealant around the hole and insert the transducer, ensuring a watertight seal. For transom mount installation, select an appropriate location on the exterior of the hull, ensuring it is below the waterline and away from any interference.

There are a variety of ways to mount a depth finder on an aluminium boat. One way is to use a transom mounting plate, which requires drilling only two holes for installation and allows for future adjustments without drilling additional holes. Another method is to use a piece of poly or PVC board, attached to the transom with marine epoxy, eliminating the need for drilling holes. Alternatively, you can drill holes and use caulking or silicone to seal them, ensuring a secure and watertight installation.

Choosing the right sealant for holes

When mounting a depth finder on an aluminium boat, you will need to seal the holes created by screws and bolts. There are many sealants available on the market, so it is important to choose the right one for your boat.

Firstly, you should consider the quality and effectiveness of the sealant. Look for a product that is specifically designed for use on aluminium boats, and read customer reviews to get an idea of how well it works. You could also test a small amount of the product on your boat to see how it performs. An effective sealant will fill even the smallest holes and cracks, creating a strong, durable, and flexible seal that is resistant to shocks and vibrations. It should also be able to withstand strong movements and resist peeling or cracking.

The ease of application is another important factor. Choose a sealant that is convenient to apply and does not require any complex mixing or preparation. Some products can be applied with a brush, roller, or spray, while others may require a caulking gun. Always follow the manufacturer's instructions and safety guidelines when applying the sealant.

When selecting a sealant, consider its versatility and flexibility. Choose a product that can be used on a variety of surfaces, not just aluminium. This will allow you to use it for other sealing jobs on your boat or in your home. Additionally, look for a sealant that is non-toxic and environmentally friendly, especially if you plan to use it near water or plants.

Finally, consider the care and maintenance of the sealant. Choose a product that is easy to store and has a long shelf life. Follow the manufacturer's instructions for storing and using the sealant to ensure that it remains effective and does not damage your boat.

• Travaco Marine-Tex RM330K Gluvit Epoxy Sealer: This product provides superb protection for aluminium surfaces and can fill even the smallest cracks. It is easy to apply, dries quickly, and is durable. However, it turns slightly brownish when dried, so you may need to paint over it.
• TotalBoat Aluminum Boat Leak Sealer: This leak sealer is effective for sealing small holes and leaks. It can be dispensed automatically with a caulking gun and is easy to apply. However, it must be used at a temperature of at least 40°F for the best results.
• Amazing GOOP 5400040 Coat-It Epoxy Sealer: This sealer offers toughness and durability, thanks to its kevlar fibre composition. It has quick-drying properties and can seal small leaks and holes in just a single coat. However, the container is of poor quality and may be damaged if mishandled.
• Hy-Poxy H-450 Alumbond Aluminum Putty Repair: This repair kit is designed for use on aluminium surfaces and allows you to dispense the exact amount of sealer you need, preventing waste. It is also versatile and can be used on other surfaces such as radiators, tanks, and pipes. However, it takes a while to thicken when mixing the two parts.
• Flex Seal Liquid Rubber Sealant Coating: This liquid rubber sealant is easy to apply and can be used to seal cracks and holes in a variety of ways. It creates a super-strong flexible rubber seal that prevents corrosion and rust. It is also non-toxic and non-hazardous. However, it has a strong smell that may be unpleasant for some users.
• Gorilla Waterproof Patch and Seal Spray: This spray sealant is extremely easy to apply and provides a self-levelling, even coat. It is versatile and can be used on a variety of surfaces, including gutters, roofs, windows, and pipes. However, like the Flex Seal product, it also has a strong smell.
• Red Devil 0785 StormGuard RTV Silicone Sealant: This small-packaging sealant is ideal for minor leak issues and quick repairs. It has quick-drying properties and creates a durable, water-resistant seal that can last for years. It can be used on both dry and wet surfaces and offers excellent adhesion and flexibility. However, the packaging could be improved.
• Eastwood Epoxy Steel Aluminum Primer: This product is an activator that is designed to be mixed with an epoxy primer to create a high-quality sealant. It is easy to apply and provides corrosion resistance and excellent adhesion. It can also be used on surfaces other than aluminium. However, the container could be of better quality.
• 3M 5200 Marine Adhesive Sealant: This sealant is known for its strength and ability to maintain its bond even below the waterline. It is easy to apply and does not require any mixing. It cures within 5 days and offers excellent flexibility and durability. However, the tube or funnel that comes with it is not very useful.
• LR Liquid Rubber Waterproof Sealant: This environmentally friendly, water-based sealant provides high-quality protection for aluminium surfaces and can be applied like regular paint. It offers flexibility and durability and can be used on a variety of surfaces. However, it has a strong paint-like odour that some users may find unpleasant.

Drilling holes vs using a mounting plate

When it comes to mounting a depth finder on an aluminium boat, there are two main options: drilling holes or using a mounting plate. Both methods have their own advantages and considerations.

Drilling Holes

Drilling holes to mount a depth finder directly to the transom of an aluminium boat is a common method. This approach requires careful planning and execution to ensure a secure and watertight installation. Here are the key steps:

• Determine the position of the depth finder: Consider the placement of high-speed skimmers, rollers, and rivets on the boat to avoid interference.
• Mark the drill holes: Hold the depth finder against the transom and mark the drill holes with a cordless drill and a metal drill bit.
• Drill the holes: Ensure the holes are slightly larger than the screws to prevent stripping.
• Seal the holes: Use marine-grade silicone to seal the holes and create a watertight seal.
• Attach the depth finder: Secure the depth finder with screws, being careful not to overtighten.

Using a Mounting Plate

Using a mounting plate, also known as a transducer board, is an alternative method that reduces the number of holes drilled into the boat. This method offers more flexibility for future adjustments:

• Prepare the mounting plate: Purchase or cut a mounting plate to the appropriate size for your boat and transducer.
• Position the mounting plate: Hold the plate against the transom and mark the drill holes.
• Drill and seal the holes: Drill the holes, apply marine-grade silicone, and drive the screws to secure the plate.
• Mount the transducer: Follow the manufacturer's instructions to mount the transducer onto the plate.

Comparison

Drilling holes directly into the transom provides a secure and straightforward installation. However, it requires more holes to be drilled, which may be a concern for some boat owners. Using a mounting plate requires drilling fewer holes and offers the advantage of being able to move or adjust the transducer in the future without drilling additional holes. This method may be preferred by those who want more flexibility or are hesitant to drill into their boat.

Cabling: how to route the transducer cabling

Cabling is an important aspect of installing a depth finder on an aluminum boat. Here are some detailed instructions and considerations for routing the transducer cabling:

Firstly, it is important to identify the best route for the cabling to ensure it is protected and secured properly. One suggestion is to run the cable "right up and over the transom and then along the gunnel or where the cable would be most protected". It is recommended to avoid putting screws on the outside of the transom for cable holders or similar attachments.

Secondly, consider using cable management clips to neatly secure the cable in place. Surface mount clips are available, and these can be useful for keeping the cable tidy and out of the way.

Thirdly, when running the cable, be mindful of other components in the boat. In some boats, there may be a tunnel or cavity where the cable can be fed through, potentially alongside other wiring and components such as steering cables. If you need to remove panels to access this area, be cautious and use the appropriate tools to avoid damaging screws or other fixings.

Finally, if you encounter resistance when pulling the cable through, try pulling it from the opposite direction in small increments. This can help to navigate around any obstacles or tight bends in the routing.

By following these steps and considerations, you can effectively route the transducer cabling for your depth finder installation on an aluminum boat.

The best location for the depth finder unit

When deciding on the best location for the depth finder unit, there are a few key factors to consider. Firstly, the unit should be placed in a spot that is easily visible and accessible while sailing or operating the boat. This ensures that you can quickly glance at the information without taking your attention away from your surroundings. Secondly, it is important to consider the cable length of the depth finder when choosing its location. The cables will need to reach the transducer and the power source, so the unit should be positioned in a way that allows for proper cable management.

In a tiller setup, one popular location for the depth finder unit is on the driver's seat or the bench beside the driver. This position keeps the unit within easy view while underway, but it is slightly awkward as you need to look back to see it. Alternatively, you can mount the unit on the left or right side of the boat's rail, using a Hobie H-rail or a Ram swing-away adjustable mount for stability and adjustability. If you prefer to have the unit in front of you, consider mounting it on the dashboard or bulkhead, ensuring it is secure and protected from water exposure.

For boats with a bow-mounted trolling motor, the location of the depth finder unit becomes more flexible. You can choose to have it near the driver for easy viewing or move it towards the stern to keep it out of the way. If you plan to use the trolling motor at the bow, consider getting a mount for the unit near the bow as well. This way, you can move the unit between the bow and stern depending on your needs.

When deciding on the best location for the depth finder unit, it is important to consider your fishing style and the type of boat you have. For example, if you are bass fishing or crappie fishing, having the ability to move the unit around or have multiple units can be advantageous. Ultimately, the ideal location for the depth finder unit is one that provides good visibility, accessibility, and ease of use while complementing your fishing style and boat setup.

Powering the depth finder

Once you have your depth finder, transducer, and display unit, you will need to connect the power and transducer cables from the depth finder unit to the corresponding outlets on your boat's battery.

Make sure each connection is twisted tightly together and securely attached with electrical tape. Double-check for any exposed wires or loose connections before moving on.

If your boat has a circuit board, connect the power line to one of the free outlets. If the motor runs directly off a 12-volt battery, attach the power cable to the battery with an inline fuse.

If you are installing two displays, one at the bow and one near the driver's seat, you can network the second display to run through the transom transducer. However, attaching a second transducer to the trolling motor will offer a different view of the structure and fish.

A word of caution: always exercise extreme caution when running power cables and batteries to avoid damage to electronics or the boat.

Frequently asked questions