Mast envy..

[Gold Rock]

May not have enough info to give from the comfort of my bunk, but I've been curious about this for a long time. I have a Townsend 30. Think H-28, but enlarged just slightly. 29' 10" LOD; 25' 6" LWL; 9' 2" beam; appx. 18,000 disp. in liveaboard trim. It's rigged as a cutter. Thing is, my mainmast is a mere 36' 6" above the waterline. The boom is just a tad over 13'. This has always seems excessively short to me. I used to moor next to a Catalina 30, which had 8 or 9K less displacement and must have had at least 4 feet more mast height. The boat sails well, but is a complete turd in less than 10 kts. Does this strike anyone as absurdly undersized, or just 'conservative'? Thx.

Chuck

[Tom Hunter]

What is the sail area?

I have a shorter mast, somewhat heavier boat, that is beamier and longer on the water line. Main is 548 sqr feet jib is 171. But its probably very different from your boat and a bad comparison.

[JimD]

Mast envy? Could be worse:

http://home.xtra.co.nz/hosts/david77/Mozambique.jpeg

(sorry, couldn't resist - I'll delete it if you like)

[rbgarr]

I think the nine ton weight is the problem. It's just a lot of weight to ask a 400 sq. ft (?) sail area to push on a 25 foot waterline.

[outofthenorm]

Chuck, is it a gaff rig or marconi, and is it the original rig? Any pics?

- Norm

[Tom Hunter]

and I forgot to mention, my boom is as long as your boat is on deck.

[Gold Rock]

The main is appx. 190 sq.ft., foretriangle appx. 200 sq. ft. if I'm doing the math right. Just the area of a triangle, right? Lenth of foot x length of luff divided by two. Doesn't seem like much area even of I shed a few thousand pounds. As far as I know, the rig is original, but then, no way to verify. It's marconi rigged. I'm probably set if I want to round the Horn, but otherwise... Never have tried posting pics, seems like a lot of work. Maybe I'll give it a shot tonight.

[paladin]

and my boat LOA wuz more'n your mast and boom together.....na..na...na.....:D ......Not knowing how your boat is set up, it does seem to be a heavy boat for the sail area......general rule is that 100 sq. feet of efficient sail will produce 1 hp in 10 knots of wind......but before you add a taller mast etc.....you need to check stability and balance of the boat......

[Gold Rock]

Oh, I wasn't set on doing anything about it really. I was more curious to know if anyone thought it was as unusual as I do. As I say, I'm a liveaboard and carry around a couple thousand pounds of stuff that is rather above and beyond what the average weekender would have. All said, it sails quite well, it's just, uh, deliberate.
Paladin, I have mused about one scenerio. Currently, the backstay attaches to the transom, and the headstay is on the end of a bowsprit of 2.5 ft. or so. The backstay limits the boom length. Couple of years ago I drew the sail plan on paper, calculated the sail CE, then drew a boomkin long enough to allow me to lengthen the boom by 1.5 ft. I then drew a longer bowsprit such that the new sail plan retained the exact CE as before. The point was to see how much sail area I could add without altering the sail CE as the boat is very well balanced right now. If the CE doesn't move, am I overlooking any other factors of signifigance that might change for the worse? Or would the altered sail plan change the handling even though the CE doesn't change? As it turned out, I only picked up less than ten percent more area by this excercise.

[Tom Hunter]

Sorry if it seemed I was bosting about the size of my boat, boom or what ever. That was not my intention, I was just saying that the boom on the pinky is 29' long vs 13 feet on the cutter.

On a thread titled Mast Envy I was trying to make the point that a longer boom also adds to sail area. Of course Goldrock has since pointed out that his backstay limits the length of the boom so no adding sail area that way.

I don't have enough experience to suggest what to do, other than talk to a naval architect, but I can offer up some information for comparison.

Goldrocks boat is 18,000lb Vs. 20,000 for the Pinky. He has 390 Sqr feet of sail Vs. 748 on the Pinky. The Pinky's designers got the larger sail area by placing the mast very far forward, putting on a low aspect gaff rig with a 29' boom (hence my comment) that ovehangs the stern and adding a bowsprit to give the jib a place to be.

Very different boats but I think the ratio of sail area to displacement is relevant one boat having 43 sqr feet per ton and the other having 75 and I am including some details about the pinky because its helpful to understand how the original designers got to the sail area.

[outofthenorm]

The short stick could mean that the boat was originally a gaffer with running (or no) backstays. You can spread a lot more sail for a given length of mast that way. Just speculation of course.

- Norm

[Gold Rock]

No worries Tom, I got your drift right out of the gate. There's a marvelous variety of rigs out there, and it's that very diversity that gave me pause to consider my own. Doubt strongly that this was ever anything other than what it is now is Norm. Mast is decked stepped, built up rectangular section, and there's no sign of conversion. Nope, it was either built this way, or someone lopped off a lot of stick at some point in the past. Lucky me.

[John B]

I've done exactly what you're talking about Goldrock, and there's no great deal to it. Things change a bit when you start talking taller rigs but within the height you have its really not an issue. choose a theoretical clr point on your hull as a datum ( push the boat off the dock until you find the middle of the boat)and configure your new centre sail area as the same % lead as your existing if you're happy with it.
Its the sort of thing you do when you think you might be up for replacing your headstay / backstay and due for a couple of new sails eh.

[donald branscom]

Mast envy? Could be worse:

http://home.xtra.co.nz/hosts/david77/Mozambique.jpeg

(sorry, couldn't resist - I'll delete it if you like)

DON"T DELETE I love the excitement of sailing photos!
I guess that one is not a turd. Five person crew too!

[Gold Rock]

Thanks John. It did seem like the variables and parameters I was working with were not likely to produce significant changes. I am due for new standing rigging soon. Hmm. Oh, and Jim and Don, I do appreciate the visual update on the L.V. cup series. Kinda sloppy foredeck work with that asymetric, must be the 'B' team.

[Tom Hunter]

Goldrock,

I did a little looking around based on your describing the Townsend 30 as "think of an H-28 but enlarged just slightly."

There are a number of ways of looking at the size of a boat. One is length, another is tonnage.

Your boat may be a few feet longer than an H-28, but measured by tonnage it is twice as large 18,000 lbs Vs. 9,000 for the H-28.

H-28 is designed with 343 sqr feet of sail, you said you have 390.