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Okay, this is embarrassing and stressful . . . last week I hauled my 330 for some routine maintenance including a bottom job. 5 years ago, I repainted the boot stripe. As I recall, at that time, I raised the stripe approximately 3" above what I thought was the original factory waterline. Even so, for the past 5 years, the boot stripe was always partially submerged. So after the boat was blocked, I measured the draft of my 330 and was shocked to see that I am drawing 5'6"!!!! The 330 is supposed to draw 4'10" per the owner's manual. What is going on here? I have 3 wet cell batteries, a monitor on the stern and a cruiseair AC unit; otherwise I am not heavily loaded and have the standard fuel and water tanks. What is going on here? Is this an aberration? I have been under the impression that lots of folks draw 2-4" more than the stated draft . . . but 8" WHAT IS GOING ON HERE?
TIA (hope you're all well)
Matt
I think it's easy to underestimate the weight of the standard equipment and ordinary whatnot we carry aboard. Ground tackle, dock lines, spare parts, spare lines, safety gear, books, galleyware, etc., etc. And then there's the beer. When decommissioning every autumn, I'm always amazed at how many ice bags full of stuff get carried off Yankee to the truck and how her waterline drops. Look at all of that growth suddenly exposed - no wonder we were getting slow! I'll bet the design waterline didn't account for all of this "live load."
I tried to find the number for Cape Dorys, but could not. If you want to do the math, here is what Ted Brewer has to say about it: POUNDS PER INCH IMMERSION (PPI): The weight required to sink the yacht one inch.
It is calculated by multiplying the LWL area by 5.333 for sea water or 5.2 for fresh.
The PPI usually increases as the hull sinks into the water as the LWL area is also increasing due to the shape of the hull above water
The Pounds per square inch immersion for the CD33, which I would assume it would be very similar if not the same for the 330 is 810 pounds. Did you measure accurately with a level and tape? Could there be some discrepancy in the measuring method at all?
Most of the Alberg CD designs I have seen squat at the stern pretty easily. One 30 in our marina has a raised waterline too.
Paul D. wrote:The Pounds per square inch immersion for the CD33, which I would assume it would be very similar if not the same for the 330 is 810 pounds. Did you measure accurately with a level and tape? Could there be some discrepancy in the measuring method at all?
Most of the Alberg CD designs I have seen squat at the stern pretty easily. One 30 in our marina has a raised waterline too.
Hey Paul -
No, I just measured from the scum line to the ground and then subtracted the height of the blocking. It could be off by as much as an inch but probably not much more than that . . . and that is little consolation . . .. 810 sounds familiar, and, as noted above, I would expect that number to increase as the boat sat deeper in the water (and the waterline lengthened). I work pretty hard to keep weight off the stern . . .. What do you draw?
Matt
The Far Reach is a CD 36. The PPI is 900 lbs. We sailed for the West Indies two years ago with waterline raised 3". We were right on our marks when we departed. Last summer we raised it two more inches. You probably could not fit as much on a 33 as we had on our boat when we took our departure even given the fact we did not have an engine. We carry 230lbs of lead pigs on the keel below the location of the old inboard. We also care 140 lbs of spare anchors on top of the lead pigs. Additionally, We carry 300' of 5/16 HT chain and a bronze windlass. We had six months of provisions, all my tools, to include my rigging vise, drills, a sander, a grinder, varnish, paint, a hard dink, an inflatible, an outboard, etc. I think we were about 18,500 lbs total displacement. We were probably carrying about 3000 lbs of gear. But that's just an educated guess. With 5000 lbs we would only add another two inches so that would only put us down a total of five inches.
There is no way you have over 6,500 additional pounds on your boat without knowing it. Not possible.
I think the best way to get an accurate measurement is with your boat level left to right and a laser level mark on the bottom or your keel. Use a tape meausre from the scumline down to the laser mark.
I draw 4' 10" but I guess I only assume that. I've always called it five feet. While I have never measured it specifically I have touched sand bottom right around that under-five-foot-mark. This was after I calibrated the new depth sounder, so right around five foot is my somewhat educated guess. Keep in mind Femme is in the less dense, fresh water of Lake Superior rather than salt water. I don't know what is going on with your waterline - since the hulls are not cored they cannot get saturated. I think John's suggestion of somehow getting a more accurate measurement would be my next step to decipher this issue.
Yes, I try to keep weight off my stern too. Our boats probably shouldn't have davits and big biminis with solar panels and radar back there. I have the original 40lb autopilot motor right aft in the lazarette and the batteries, fridge compressor and AC charger right in the port cockpit locker. Fuel tank to starboard. And that is about all the weight, besides humans, I want to have back there. I don't even keep the stern anchor and line there.
Yesterday I helped winterize my buddy's Hunter 380 as he hurt his back. I was amazed at the width of the aft sections (the cockpit could well be a party Jacuzzi.) and the amount of stowage, room for external gear etc. The weight handling capacity of that wide stern is probably 20 times our boats' abilities and then some!
I guess since we have boats actually designed to sail we have to put extra thought into stowage of items for proper balance.
Our P/O raised the waterline of our 31 at some point, probably because our 31 squatted a bit, leading to fouling of the waterline aft.
I agree with the advice that all our gear probably weighs a lot more than we think, maybe ton or more on our boat, including batteries, ground tackle, dinghy/davits, tools, food/drinks, too many books, spare parts/fuel tanks, etc.
I'm not sure what figure the designer used to place the original waterlines at the factory. Full tanks? Half full? Lots of gear or bare boat? Dave Perry might know, though he recently retired from Robbinhood.
Terry
Jennifer & Terry McAdams
Kearsarge, New Hampshire
Mahone Bay, Nova Scotia
CD 31 #33 "Glissade"
Way too many other small boats
Terry concur. I don't think Carl Albert never intended to see all the stuff hung off the back end of boats so commonly today. That doesn't even include all the extra equipment carried today from generators to AC, inflatables to outboards.
Part of the work up to long range cruising is to determine what you need to carry and where the top of the bottom paint needs to be. I don't know an easy way to do it without just doing it and see what happens then haul and raise the waterline accordingly. PPI is probably the most helpful. We were not far off on our estimation for our trip to the West Indies. My mistake was not thinking about how much paint I should have above the fully loaded waterline. Once we understood where it needed to be we had to haul and raise the line another 2.25 inches.
Squatting sterns also induce weather helm. So I think it's critical that as we load our boats down we work to keep them evenly loaded so the new waterline is as close as possible to remaining parrellel with the original LWL even if we are sitting 5" lower in the water.
