Installing A Hardtop On Your Thompson Boat: A Step-By-Step Guide

Thompson boats are a well-known boat builder that offers a range of vessels for sale, from 15 to 34 feet in length. They have been in the marine industry for years, with models dating back to 1960. If you're looking to add a hardtop to your Thompson boat, you might be considering a custom build or purchasing a used one. While it's possible to add a hardtop, it may be a challenging and costly endeavour, with potential costs ranging from $3200 to $10,000. Before embarking on this journey, it's essential to weigh the benefits of a custom hardtop against the option of buying a boat that already has one.

Find the right materials for the frame and roof

When it comes to finding the right materials for the frame and roof of your hardtop Thompson boat, there are a few options to consider. The most common materials used for hardtop boat frames are aluminium and wood.

Aluminium is a popular choice due to its lightweight and durable nature. It can be easily bent and welded to create the desired frame shape. When using aluminium, it is recommended to use pre-anodized 6063 aluminium pipe, which can be sourced from suppliers like Taco Metals. For the main upright supports, schedule 80 2" pipe is often used.

Wood can also be used for the frame, especially if you want to create an exact replica of the boat's bridge. You can trace the lines of the bridge with cardboard and then construct a wooden frame to match.

For the roof, fibreglass is a popular choice as it is strong, stable, and lightweight. It can be custom-made to fit the size and shape of your boat. Some companies offer standard and custom-made hardtops made entirely of fibreglass, ensuring robust stability and lightweight construction.

Another option for the roof is to use marine-grade plywood, especially if you plan to walk on top of it. You can glass the plywood in marine-grade resin and add a layer of paint for UV protection and aesthetics.

Additionally, consider the use of stainless steel hardware for bolting the frame and roof together, ensuring durability and corrosion resistance.

Remember, the choice of materials depends on your specific needs, budget, and the availability of resources. Always consult with professionals or experienced boat builders before making your final decision.

Consider wind resistance and towing

When adding a hardtop to your Thompson boat, it's important to consider the impact on wind resistance and towing capabilities. Here are some detailed instructions and considerations to keep in mind:

Wind Resistance:

• The addition of a hardtop will increase the wind resistance of your boat, particularly when towing at high speeds. Ensure that the hardtop is securely attached and can withstand high winds. Consider using reinforcement patches and multiple lines of stitching to keep the cover secure.
• Choose the right materials for your hardtop. Polyester and acrylic fabrics, such as Sunbrella, are commonly used in semicustom and custom covers. Polyester is typically used for universal covers, with higher denier (weight) resulting in better quality.
• Ensure a tight fit for your hardtop to prevent air from getting underneath during towing, which can cause it to pull free or fail. Custom and semicustom covers provide a tighter fit tailored to your boat's contours and accessories.
• Consider the design of the hardtop to minimize wind resistance. A curved or domed shape can improve airflow and reduce the impact of headwinds.

Towing:

• When towing your hardtop Thompson boat, choose a reputable towing company with experience in boat transportation, such as Tampa Boat Towing Service. They will have the necessary equipment and expertise to ensure a safe journey.
• Use the right equipment, including the correct size and type of tow rope, winches, straps, and fenders. Ensure all equipment is in good condition and properly maintained.
• Secure the boat properly by attaching the tow rope securely to both the boat and the tow vehicle. Tighten all straps and winches, and ensure all lines are free of knots or tangles.
• Monitor weather conditions closely during towing. High winds can be hazardous, so pay attention to wind speed and direction. If conditions become too dangerous, stop and wait for them to improve.
• Drive slowly and carefully when towing in high winds, and avoid sudden turns or stops. Regularly monitor the tow rope to ensure it remains secure and shows no signs of wear and tear.
• Use extra lines and fenders to minimize the boat's swaying and protect it from debris kicked up by the wind.
• Always have a backup plan in case of unexpected issues during towing. This includes a way to contact help and a plan for potential problems, such as a broken tow rope.

Plan the design and structure

Planning the design and structure of a hardtop for your Thompson boat involves several key considerations. Firstly, you'll want to decide on the materials you'll be using. For the frame, you can use stainless steel tubing with a diameter of 35-38mm and 3mm thick walls. This will provide a sturdy base for your hardtop.

For the roof, you have a few options. One approach is to use marine-grade plywood, either 1/4" or 1/2" thick, depending on whether you intend to use it as a sun deck. You can then cover the plywood with resin and fibreglass mat for added strength and protection. Alternatively, you can use a more lightweight material such as XPS (Extruded Polystyrene) foam board, which is strong, flexible, and water-resistant. This can also be fibreglassed for a smooth finish.

When designing the shape of your hardtop, you may choose to follow the existing curvature of your boat, especially if you want to mount solar panels or other equipment on top. This will ensure that the structure can bear the weight without sagging. Consider adding features like an edge lip to keep the overall shape and prevent sagging over time.

Another important aspect to plan is the structural support for your hardtop. You can use plywood bearing blocks and large aluminium fixing plates, laminated into the beams and core with thickened epoxy, to create strong attachment points for the stainless steel support poles. Ensure that your design includes a sufficient number of support points to counterbalance the weight of the hardtop.

Lastly, consider any additional features you may want, such as lighting or equipment to be installed on top of the hardtop. Plan for any necessary wiring or mounting requirements during the design phase to ensure a seamless integration.

Prepare the boat for installation

To prepare your boat for the installation of a hardtop, there are several steps you can take to ensure a smooth process. Firstly, it is important to measure the area you wish to cover with the hardtop. This will help you determine the appropriate size and fit for your hardtop structure. You can use a measuring tape for this step, taking measurements of the desired coverage area.

Once you have your measurements, it is time to choose the right materials. For the frame, consider using stainless steel hardware and fittings, such as those with a size of 1-3/8 or 2 inches. This will ensure durability and corrosion resistance. For the upright and crossbars, aluminium tubing is a good choice. When selecting the roofing material, opt for marine-grade plywood, preferably with a thickness of 1/4 inch. This type of plywood is designed to withstand the harsh marine environment.

Before you begin construction, it is advisable to create a prototype or template to work from. You can use cardboard to create a prototype, assembling the panels with tape, monofilament line, or metal wire. This will help you visualise the final structure and make any necessary adjustments. If you have an existing dodger that you are happy with, you can use it as a starting point and make improvements based on your specific needs.

Consider the height of the hardtop and ensure it does not obstruct your view from the helm. Think about the placement of additional features such as stereo speaker boxes, power outlets, reading lights, and grab rails. You may also want to incorporate openings or hatches for improved ventilation.

Finally, prepare the boat by gathering the necessary tools and equipment. This includes items such as epoxy resin, fiberglass cloth, putty knives, sandpaper, paint or gel coat, eye straps, wood screws, and a bimini mount. Ensure you have a clear and organised workspace to facilitate the installation process.

Seek professional help if needed

If you are unsure about any part of the process, or simply do not want to attempt it yourself, it is best to seek professional help. There are companies that specialise in building hardtops for boats, and they can provide a high-quality product that is customised to your boat's specifications. This option may be costly, but it will ensure that your hardtop is safe and secure.

For example, WMW Marine and S-S Marine are two companies that have been recommended by Grady White Boat owners for their expertise in building hardtops. You can also look for local companies that have experience in building hardtops for boats, as they will be able to provide a customised solution and may even come to you to take measurements and install the hardtop.

If you are looking for a more affordable option, you may be able to find a used hardtop that can be installed on your boat. However, this may require some modifications to ensure a proper fit, and it is still recommended that you seek professional help for the installation process.

When it comes to actually installing the hardtop, it is important to note that this is not a simple task and can be quite challenging. It will likely require multiple people and a good amount of time to complete the installation safely and securely. If you are unsure about your ability to install the hardtop yourself, it is best to leave it to professionals who have the necessary experience and equipment.

While it is possible to build and install a hardtop on your boat yourself, it is important to recognise when a task is beyond your skill level. By seeking professional help, you can ensure that your hardtop is installed correctly and safely, providing you with peace of mind and a high-quality finished product.

Frequently asked questions