Towing a Catalina C30 1983

Sep 28, 2025
59
Catalina C 30 MK1 1983 Stockton Lake Missouri
The previous owner said the aft stay tensioner is not for warping the mast.
I own a 1954 wooden Star (International) “Wishing Star” or it owns me that is made to warp the mast. The mast is a toothpick.
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Last edited:
Sep 24, 2018
3,754
Catalina 30 MKIII Chicago
I suspect what the boat yard manager was referring to was that compared to other 30' boats, the Catalina has a bigger and heavier section. This is true. We in the C30 family call them telephone polls and they are heavy stiff sections. Very stiff and when somebody askes about "bending the mast" with the aft stay tensioner, we just laugh. It don't bend. I have a very powerful aft stay tensioning system, but it is not for bending the mast. It is used to tension the forestay to reproduce luff sag.

With the exception of the very oldest boat built in 1975 and 76, the mast and boom of the C30 remained the same for the Mk1, 2 & 3. From day one, they offered 4 configurations. The two most common are standard and tall rig w/ bow sprit. You could also order the boat with a standard rig with bow sprit or tall rig without bow sprit but those are very uncommon. The rigging size stayed the same for all years although they did make some changes to the chainplates in the middle of the Mk1 run.
That is some excellent info. They made the split in the backstay higher for the walk through transom for the MKIII's. I think the MKII's might have the best cockpit layout
 
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Sep 28, 2025
59
Catalina C 30 MK1 1983 Stockton Lake Missouri
That 10,200lb is the weight of the bare boat as it left the factory (assuming a Mk1). They never changed the displacement from what it was listed as in 1975 and the Mk2 boats were all much heavier out the door. The last time I had mine transported, it weighed in at 15,000lbs. That was with most of the stuff I could take out, removed.
Hayden,
I have done some design work. Even with everything you can think of you just can’t think of anything. I did a spreadsheet and 1/4 scale model of my Diotima.
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I made the hull frames, planking and decking, the percentage larger in the model as related to the wood differences species and weight it to estimated weight as well as a lot of other things like center of buoyancy, waterlines at different angles according to the Dellenbaugh Angle, but I never felt confident in my Dellenbaugh Angle.
The Dellenbaugh Angle is an approximate measure of a sailboat's sail-carrying ability and stiffness, which predicts the angle it would heel under a specific wind pressure.
But with the model I could calculate the center of buoyancy at different waterlines angles anyway.
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I don’t know how Naval architects calculate this without spreadsheets back in the day.
I didn’t use a 3-D computer program, because it seemed like you would take the sport out of it and I would miss out on a learning opportunity.
Most everything is dependent upon how accurate the Table of Offsets are.
I did a lot of pre-faring in different charts in SS, you can see a 1/16” off clearly.
I also did a Curves of Displacement.
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Here is one of my inspiration for my Diotima a Herreshoff’s H15 or Buzzards Bay 15. Which I drew on the map of Buzzards Bay Mass.
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Sep 28, 2025
59
Catalina C 30 MK1 1983 Stockton Lake Missouri
None of the stuff I did above helped me be a better sailor. I think that if the seat of your pants aren’t wet from one thing or another you haven’t really been sailing.
 

jssailem

SBO Weather and Forecasting Forum Jim & John
Oct 22, 2014
23,632
CAL 35 Cruiser #21 moored EVERETT WA
I think that if the seat of your pants aren’t wet from one thing or another you haven’t really been sailing.
I am ok with the “One Thing”… it is the “another” that makes me feel a bit squiggly.
 
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