Hello from Kanchanaburi, Thailand. I am building a couple of Kaholo 12'6" SUP boards. We will be using them on a (sometimes shallow) river. Our clients can sometimes run the boards onto the (rocky shore) and the boards will take some damage. I think it will take damage. I am thinking either triple up on the fiber glass only on the first 50cm or so of the v shaped underside an inch either side of the v center OR some type of rubbing strake ? Any thoughts? Mid-term, say once per year it is likely that it will need maintenance, but I am OK with that. Also, we will be painting the boards white (on the advice of another friend), due to the high UV and sunshine here. Any thoughts on protecting the paint from the wear and tear of paddle blade rubbing on the sides, or just accept it will happen and repaint at the end of the season? Thank you in advance for thoughts / help / tips. Troy from SUP Hire (Thailand)
Sawadee ka Kanchanaburi
Fiberglass, while important for strength, is not particularly resistant to abrasion. It's very easy to scrape through many layers of fiberglass if it is rubbed against a rough surface.
It sounds like you need to consider both strength as well as abrasion f you are using these for clients.
For strength, I would definitely go with 8 to 12 oz of glass (3 layers or 4 oz or 2 layers of 6oz) of glass for some extra strength in the bow area and possibly even the bottom and deck you might want to double up your layers. but to resist abrasion you will need to do something else.
On kayaks we will typically handle it one of two ways:
one is with dynel strips applied with epoxy and graphite. This is a link to a kit that clc sells but you can buy dynel cloth if you are making a lot and make your own https://clcboats.com/shop/products/boat-building-supplies-epoxy-fiberglass-plywood/marine-epoxy-fiberglass/kayak-rubstrip-kit.html
The second way h is to use a product called keeleazy: https://www.keeleazy.com/?srsltid=AfmBOop0PWGyCiBf8bvbt7LZ20ZW5hXKz-XevSiDH514uZyUHBLzDJbP
Some folks also consider using partial rounded brass strips that they screw into the hull. You can also glue/screw a sacrificial wooden strake.
The dynel and keeleazy can also be used in areas where you expect paddle strikes.
I hope this was helpful. used to work in Bangkok in the early 2000s....miss being there.
best,
h
This is VERY useful advice, thank you.
We have gone with the sacrificial strake concept starting from about 8 inches from the tip of the nose to the halfway point + a rubber bumper strip of re-puposed bicycle tyre for the curved nose section which will inevitably take the biggest impacts / beating. If this was my own board I would go for beauty / streamlining and take care not to bash it, but since our clients will use the board, I have gone with durability (we can replace the sacrificial strake at the end of each season).
PS. Do come back and visit Thailand and our team at www.supkanchanaburi.com