This past weekend we where showing our boats at a small local show and the most frequent questions have to do boat capacity. As I am getting ready for another show in just over a week and am beginning to make preparations I am giving this some more thought, as I want my signage to give as much clear information as possible. I have in the past done research to see what others are doing and thought I would take another look and see what they are doing now.
The first thing to know is that nowhere is it written that there is a particular way in which this determination must be made and the first thing that came up when doing an on-line search was this article http://www.kayakfishmag.com/features/kayak-weight-capacity/ seven companies, seven methods some even telling you they then either fudge and or real world test.
My method is to use the ABYC* standard, though even it can be used in different ways, depending on a decks camber and whether or not a boat is measured at the sheer (the point where the hull and deck meet) or just before water can get in at the hatches. I use the lowest point of the sheer line and sink the boat to this point in the computer then use this number in a spread sheet that is based on the ABYC* standard and use this for the basis of my capacity number. The ABYC* standard also works the weight of the boat into the formula so my capacity number is above the weight of the boat.
What this means is if a boat says its capacity is 175 pounds it is not going to sink at 176 at 200 you will not likely feel much difference in its handling. This number will tell you in the case of my boats that if you weigh in at 190 and you want to haul a weeks worth of gear you probably have the wrong boat for the job. You also need to take a look at the boat and use a touch of common sense our Little Lake 10 has a listed capacity of 148 and looking at the distance between the waterline and the deck in the pictures and knowing that the boat will only sink one inch for every 58 pounds that at two hundred pounds you could paddle it. Really! It’s a ten foot boat with a 22.5 inch beam you would likely have to break a part of you that would result in some serious pain/injury to enter the boat and once in may not be able to leave. You’ve seen those comedy sketches of the guy stuck in the chair right?
When you see us at shows contained in the information on the boats displayed is something called the PPI this is pounds per inch immersion this is the amount of weight that it will take to sink the boat one inch. If you then take our capacity as your guide and you like the boat but weigh a few more pounds then the capacity it does not mean the boat will not suit you. It will depend on the use the boat will see if you are going to day paddle only it is not likely to matter, if you are going to make extended trips and carry your gear it may.
So keep asking, and for fun the next time you are in a big box or even a sporting goods store and the salesperson comes over to ask if they can help tell them you where just wondering what the PPI number was on the kayak your looking at and what method was used to calculate the capacity.
Keep in mind when you shop that how the capacity number was arrived at and what it represents matters, if it is the max the boat was designed to handle the exceeding it is risky if it is a max with fudge factor then there is room to play. Also be mindful of how much gear you plan to add, kayak fisherman in particular are real good at the just one more toy trick, the problem is all the toys add weight and often up high on the boat where it is least needed.
* ABYC- American Boat and Yacht Council they set various voluntary standards for the marine industry and though there name says American they cab often be found in the Canadian standards cited as a reference.More often than not the methods are the same in Canada and the US as more and more effort is put into harmonizing the standards.