Waterline range

[Figment]

I've been wondering about how various Tritons sit on their lines. Specifically, how deeply. I think it could be really useful to someone in the middle of a restoration to be able to anticipate how far off the DWL their boat will sit, given certain assumptions about typical load.

In my own situation, I know where my actual waterline is now, but I also know that I keep the boat very lightly loaded. I wonder how far I should adjust the line to allow for heavier future conditions.

Part of the difficulty of this issue is that I can't think of many reliable ways to compare WL height from one boat to another.
The stemstrap is one consistent reliable point. I can measure down the curve of the stem, starting from the centerline of the lowest fastener.
Perhaps another reliable point could be the transom/counter break.

I can't think of a good method for a midship measurement, though. Centerline of original rubrail trim might work, but that eliminates the information from a lot of boats due to rubrail modification. Early vs. late model might matter here as well due to the change in hull/deck joint construction method. Any thoughts?

[dasein668]

Couldn't you use the original scribes as a reference?

How thick, relatively speaking, is your laminate? There are so many variables with these boats that I think you would have a hard time drawing much of a conclusion from the data set you could develop.

But if it helps any, my boat floats almost exactly on the lower scribe. I don't know if that means I'm exactly on the DWL, or 1 to 1.5 inches deep.

I would consider my boat lightly to moderately loaded most of the time.

My boat has, relatively speaking, a thin layup?where I drilled for my seacocks it was "only" about 3/4 inch thick. Topsides, where I filled an old vent hole I had about 3/8 inch of laminate, if memory serves...

[Figment]

True, construction tolerances varied widely, and so "original" displacement varied. The information might vary widely enough to be meaningless, but that doesn't mean we can't have fun collecting it!

The scribe.... good thought. Do we know how consistent the scribe is?
Only by sanding my hull down to absolute bare glass was I able to find traces of the scribe.

the lower scribe? You have two?

[Figment]

(before some smart alec chimes in...)

yes, of course I could just figure the waterplane and do the math to learn how much lower she'll sit with the additional X-weight, but what fun is that?

[Tim]

You only need two points to determine your waterline. A midships reference is not needed if you can determine the two centerline points fore and aft; a level, planar line between the two will automatically determine the remainder of the waterline, and in the proper, aesthetically pleasing way.

I suspect the molded-in scribe lines (are you sure you only have one, Mike--I've never seen a Triton without both scribes, though sometimes they're extremely faint) are consistent between boats built from one of the (I think) two molds that were used to build these boats. There's the "first generation" mold that was used for the externally-ballasted, false keel-fitted boats up to and including #381, and then there's the "second generation" mold that incorporated the internal ballast and changes to the deadwood, beginning with #382 and going onward from there. Perhaps more than one mold was used during each of these runs; I have no idea, but assuming one mold only for each run, the scribe lines would necessarily be identical.

The lower scribe line, demarking the originally-designed point to which antifouling paint is applied, is a planar line. The upper scribe, demarking the top edge of the originally-designed boottop, is NOT planar (it incorporates some sheer) and makes a poor reference point.

I think that measuring from a pre-determined point on the stem, such as the bottom of the molded indentation containing the stem casting, to the waterline and from the point on the transom down the centerline ridge would give us some form of comparison between boats. Exactly how useful this is for those in the throes of restoration remains to be seen, but if nothing else it would be very interesting.

I do know that most Tritons I have seen in person sit higher in the water than Glissando--but also that most do not sit appropriately on their so-called "designed" waterline. I think this is largely a function of the fact that the scribed marks on the hull were based on the designed displacement of the boat, which we now know was off (light) by 1600 pounds or so. This, more than anything, leads to the traditional "squat" look. The boats do not look like they're squatting if the waterline is corrected appropriately (and this doesn't mean just raising the after portion, as is often seen).

I believe PPI (Pounds Per Inch immersion) for the Triton is somewhere around 600 or thereabouts.

[jhenson]

Tim,

The boats do not look like they're squatting if the waterline is corrected appropriately (and this doesn't mean just raising the after portion, as is often seen).

Just to clarify, are you saying the proper way to counter the squat is to trim the hull as discussed in the post about Triton berths rather than adjusting the boot stripe upward to match the typical loaded waterline?

This issue of stripe placement is sort of been a enigma to me. How, in my case where the bootstripe wasn't visible through the muck on the hull during the breif time I saw it in the water, would I determine a good place to put the stripe relative to the DWL scribe mark before it leaves my driveway? I haven't completely removed the old suspect stripe yet. If one were to err, would it be fair to say you would be better to have it a couple of inches to high.

This bootstripe step seems pretty scary to me.

Joe

[Figment]

You're right about the two points thing, of course. The midlength measurement was just a thought to reinforce the data set, as I expect that we all have our boats trimmed a bit differently fore and aft.

No, I'm not sure that I have only one scribe. There could be faint traces of another scribe yet to be discovered. That's a drawback of using the scribe as a reference..... you need to sand the boat down to nothing in order to see it.

Yeah, the bootstripe can be an intimidating bit of paint. But it's only paint afterall. (at least, that's what I told myself last year when I just guessed the stripe)

[Figment]

Kicking it off with data from #78:

Measuring down from bottom of stemstrap: 48"

Measuring down/forward from the transom/counter break: 31 1/4"

Measuring down from the centerline of the stock rubrail trim, midway between the deadlights: 28 1/2"

If you don't the original rubrail trim, you don't have it. If you do, every little bit of data helps, eh?

[Tim]

Tim,

The boats do not look like they're squatting if the waterline is corrected appropriately (and this doesn't mean just raising the after portion, as is often seen).

Just to clarify, are you saying the proper way to counter the squat is to trim the hull as discussed in the post about Triton berths rather than adjusting the boot stripe upward to match the typical loaded waterline?

Yes to both. Trimming the boat forward might help, depending on circumstance, and the "original" waterlines and boottops are almost always in the wrong place to begin with--so some adjustment and restriking is necessary for best appearance.

However, what I really meant by the above quote was that many people, when trying to correct a sqatting appearance, sort of scooch the boottop further up at the stern, while not changing it elsewhere. This never looks right and really only makes the problem worse.

This is a topic that runs the risk of making the issue more scary and complicated than it really is. Boottops happen to be one of those things that I immediately notice on all boats--my eye goes right to it, especially when something's off. Therefore, I have strong feelings on the subject, but my discussions might actually overcomplicate the issue and make it seem extraordinarily compled. This is not my intent, so try not to worry too much about it! If you get it wrong, it's a relatively simple matter to re-correct it the next year. Mine wasn't right for the first two seasons, and somehow I managed to live!

[Tim]

Before posting this, I just reviewed Figment's numbers. Wow, this is going to highlight some serious differences between boats!

Here are Glissando's measurements: (#381)

From the bottom of the stemstrap to the actual waterline: 39"

Measuring from the transom/counter break along the centerline ridge to the actual waterline: 18.5"

No original rubrail.

My boat floats with about 2-3" of bottom paint showing when lightly loaded, and just about 1/2" from the bottom of the boottop when fully loaded for a long cruise.



-----------------------------------------------------------

I also took the liberty of measuring Dasein: (#668)

From the bottom of the stemstrap to the actual waterline: 43"

Measuring from the transom/counter break along the centerline ridge to the actual waterline: 22.5"

No original rubrail.

In both cases here, the actual waterline is approximately 2-3" below the bottom of the boottop. And of course, all measurements are approximate with room for error.

[dasein668]

I also took the liberty of measuring Dasein: (#668)

From the bottom of the stemstrap to the actual waterline: 43"

Measuring from the transom/counter break along the centerline ridge to the actual waterline: 22.5"

No original rubrail.

Thanks Tim. Here is a photo for comparison.

[Figment]

well I'll be a...... I do have two scribe lines!


Oddly enough, the lower (barely discernable) scribe is within 1/4" of the actual waterline.
Even more oddly, the upper scribe is right at the top of the bootstripe that I painted by the seat of my pants last year.

[Figment]

I keep forgetting to ask.....

Has anyone found their scribe lines to be inconsistent in any way?
Is there any reason why I shouldn't use the lower scribe as a reference for leveling the boat on the hard?

[Tim]

I have found the lower scribe to be a good indication of level on two separate Tritons. It is entirely planar.

[Figment]

Thanks. I figured it should be reasonably true, but if not it certainly wouldn't be an extraordinary anomaly!

[Figment]

I was messing around a bit today, and did a quick little thing with the data above. A picture is a thousand words or so.







The top edge of the tape is the line in each case.

Well, I found it interesting, anyway.

[bcooke]

Well, I found it interesting, anyway.

Me too.

[dasein668]

Is that where Figment actually floats?!!?!!? Damn! Tim always calls my boat "the cork" as it sits so much higher than most other Tritons. I'm not sure what we're going to call your boat! I think that's around where the daysailor floated...

[dasein668]

Well, I found it interesting, anyway.

Me too.

Me three.

[Figment]

Yeah, there may be something fluky going on between my early model and your later models. There really shouldn't be that much difference.

Tim's WL is a full 6" deeper than mine. Can his boat really weigh 3600# more?

Nathan, in an earlier post you mentioned that your boat sits almost exactly on the lower scribe. The short piece of tape is at the line of my scribe, so either something's screwy with the measurements, or the scribe was moved up on the mold for later models.

I also found it interesting to note that my boat doesn't sit so deeply in the stern. I'll hyppothesize that this is because you guys have hinged-seat storage access in the cockpit, and I don't.

[dasein668]

Nathan, in an earlier post you mentioned that your boat sits almost exactly on the lower scribe. The short piece of tape is at the line of my scribe, so either something's screwy with the measurements, or the scribe was moved up on the mold for later models.

What number is your hull?

Yes, my boat sits almost exactly on the lower scribe. However, I didn't want the bottom of my boot getting wet, really, so I painted the waterline about 2-3 inches higher than that so that there is a small amount of bottom paint above the actual waterline.

[Tim]

Here's my own tape mark photo, taken in 2002, from when I corrected my waterline and boottop. There is about 6" difference between the bottom scribe (original waterline scribe) and the point to which I struck the new line. When normally loaded, the boat floats with about 2" of antifouling showing all around.

I think that's around where the daysailor floated...

Yes. The daysailor floated actually just a hair lighter than the original lower scribe mark (actual water contact). Unfortunately (well, not really, but you know what I mean), the daysailor had departed here by the time this thread got going, so I couldn't measure for the record.

[Tim]

Well, I found it interesting, anyway.

Me too.

Me three.

<<SIGH>> You leave me little choice.

Me four.

[Tim]

Tim's WL is a full 6" deeper than mine. Can his boat really weigh 3600# more?

That seems like a lot. I have a lot of stuff on my boat, but not that much. However, it is clear that I float much lower than most other Tritons, and not just when I'm fully loaded for a cruise.

My theory has always been that #381 is indeed heavier than normal, but that a large part of that must be because of some construction anamoly or another...a heavier ballast pig, or thicker hull laminate, or some such.

I have no way of knowing for sure. I really would like to weigh the boat sometime, though!

[Summersdawn]

Could it be that later boats were built with less freeboard? 6" seems like such a huge difference. I don't know that much about Tritons, but it seems like there are plenty of other anomalies, why not a change in freeboard?

[bcooke]

Tim's WL is a full 6" deeper than mine. Can his boat really weigh 3600# more?

Okay, I will bite. At the risk of being banished to the boat nerdery section... where did this number come from? It would seem to me that you would need to compute the volume of the hull at the different waterlines to come up with this number and that seems like an awful lot of math.

I would have suggested that the earlier boats were heavier but Figment's case (#78) seems to suggest that the weights varied much more erratically. A natural break in the weights could have occured when the ballast went from external to internal. I know the hull cores I have pulled from my boat (#680) don't approach the thicknesses that Tim has found on Glisssando (#381) so I can see why Glissando is heavier than my boat but that 3600# number would add up to a lot of fiberglass laminate if that was the only reason.

FWIW, I didn't do a scientific study of my waterline. I painted to the top scribe mark which proved MUCH too high. I seem to remember my boat floating pretty close to the original scribe mark. My hull is too clean to go back and check accurately now.

Back to that #3600 number. Going from a poor memory...

The boats when finally weighed seemed to be around #8000. I forget the actual weight of the ballast but isn't it around #2000? So that leaves #6000 of laminate and other boaty stuff. A #3600 difference would be more than half the total weight of the unballasted boat.

Could it be that later boats were built with less freeboard

I was first looking for a change like that too except Mike's (light) boat is one of the early ones, Tim's (heavy) boat is one of the middle ones, Nathan's and my boat (just right) are both late models.

-Britton

[bcooke]

I believe PPI (Pounds Per Inch immersion) for the Triton is somewhere around 600 or thereabouts.

Oh, never mind, I forgot how far back this thread goes...

-Britton

[dasein668]

Don't underestimate how #*!@& heavy fiberglass is... an average sized fiberglass canoe can run upwards of 3-400 lbs if it's at all chunky... The difference in hull thickness on my boat from Tim's is substantial. It may not add up to a full 3600 lbs, but it's probably closer than we might initially think...

[Figment]

Tim's boat is clearly a special case. Custom interior, and a long list of tools and spares and miscellanous other items can easily explain away a thousand pounds or so. Can't really compare #381 to other tritons.

So let's tackle the 2400# between #78 and #668

My layup is heavy. Over an inch at the turn of the bilge. A full inch at the penetration for the bilgepump thruhull in the counter. Probably 5/8" at the penetration for the head discharge.

I am willing to guess, however, that later models with encapsulated ballast are heavier than earlier externally ballasted boats. As you said, fiberglass is friggin heavy. they used a good bit of fiberglass to encapsulate that ballast, at least a canoe worth. Call it 400#, so we're down to a 2000# difference.

I think I just keep the boat really really light. No icebox. I keep a few tools and spares on board, but my list is nothing like Tim's.
I also have a pretty spartan interior. I don't have any interior pics on hand, but you guys remember Kaynee, right? That kind of spartan.

What does a stock mast weigh? I can pick my mast up and walk it around the yard myself. The mast from my Supercat was heavier (and longer and stiffer).

[Figment]

sigh. I need to raise my waterline.

In still water, it's just about perfect, a nice 1/2-3/4" above the actual waterplane. Because my dock is well up a well protected river, (as opposed to living out in a mooring field), I felt this was adequate.

I failed to account for two things:
1) the boat lies upcurrent from the dock on the outgoing tide, which occasionally tops 2knots. All of that water pushing against the keel pivots the boat against the dock, inducing quite a noticeable heel, submerging the line on the upcurrent side.
2) Oysterboats. The fleet of oysterboats that docks upriver have their own definition of "no wake", and it's amazing how much surface gunk gets slung up against the hull when they pass.

Oh and the bootstripe is white. I've scrubbed it weekly since launch, and I'm not able to keep ahead of the yellowing.

So perhaps I'm not such a cork after all!

[dasein668]

Bummer!

Easier to raise than to lower, though.

[Tim]

Go for 2" exposed bottom paint and you'll notice a distinct decrease in boottop discoloration. I got 2 seasons out of my white boot without a need to brighten it. Last fall, I cleaned it with On&Off to restore the white. It was yellowish, but not immediately noticeable with the boat in the water, fortunately.

White boots are tough under the best of circumstances. Keeping it up a bit helps, though. I used to keep boats in a river, and found that the brackish river water tended to discolor things a lot faster, somehow--full of minerals and runoff, I suppose.

I've known people to choose an entirely different--and less desirable to them--color scheme for their boats in order to avoid a white boottop. I personally would rather have hte colors I want, despite additional work, but this goes to show how much of an issue the white boottop can be.