“Twenty years from now you will be more disappointed by the things that you didn't do than by the ones you did do. So throw off the bowlines. Sail away from the safe harbor. Catch the trade winds in your sails. Explore. Dream. Discover.” – Mark Twain


7 Comments

Tuning the Rig on a Catalina 310 with a Traditional Mainsail

Catalina does provide a pretty decent tuning guide in the owner’s manual.  But a lot of the specifics in that tuning guide are more qualitative then quantitative.  So it’s difficult to judge if you have tuned the rigging correctly.  I mean how do you really judge “a 50 pound push should deflect the upper shroud about 1″ at shoulder height”?

Loos & Co. Inc. does make tension gauges that give you some quantifiable numbers relative to your rig tension.  And we have the PT-3 Tension Gauge (a tool, of course I have it). But the answer isn’t to simply put every wire to 15-20% of its breaking strength.

TENSION GAUGES

To tune the rig correctly you need to account for rake (the distance aft of the mast base that the top of the mast will bend), prebend (the bow in the middle of the mast) and performance under load. Add to that the complication that the boat wasn’t constructed with all of the shrouds precisely located an equal distance from the mast base and that split backstays need to tensioned differently than a single back stay.  This can get more complicated then simply turning turnbuckles until you get to a number.

Side note on turnbuckles.

Turnbuckle with cover

These brass turnbuckles with a built in cover that Catalina used on our C310 are horrible.  There is not flat spot to grab these with a wrench, so you have to resort to putting a large screwdriver into the slot and using that to turn.  When you actually start to really torque down on them the soft metal bends and you can’t really tension them well.  I will eventually switch these out for standard, open body stainless steel turnbuckles.

Open body turnbuckle

Back to tuning.

Here are some resources that I used to put together a rig tuning plan: Selden Masts Hints & Advice (large pdf); Practical Sailor’s Article Boat Clinic: Tuning the Masthead Rig; the C34 IA Techwiki on Rig Tuning; and the C34 IA Rig Tuning Chart.

From what I have been able to gather from Catalina, riggers and other mast manufacturers when you setup a deck stepped, masthead rigged mast with perpendicular spreaders for cruising you want the mast centered between starboard and port, a 4-6 inch rake and a 0.5-1 inch prebend.

The forestay should be set at approximately 15-20% of the breaking strength of the wire.  This is impossible to measure directly because of the roller furler. You have to measure this indirectly by the tension on the backstays. This is where it really gets a little complicated.  The angle from the bow to the front of the mast is larger than the angle from back of the mast to the stern. This means the back stays will have more power in their pull than the forestay.  The forestay is 5/16″ wire and has a breaking strength of 12,500 pounds.  So 15-20% of this would be 1,875-2,500 pounds.  Based on the angle difference I estimated that the backstays are 20% more efficient than the forestay (this is a bit of a SWAG). So that would mean that I would be looking for a tension setting of 1,500-2,000 pounds on the backstays.  The backstays consist of a single 1/4″ wire from the masthead to approximately 12 feet from the stern.  At 12 feet from the stern the backstay is split into two 1/4″ wires at a stainless steel plate.  A 1/4″ wire has a breaking strength of 8,200 pounds; the tension setting of 1,500-2,000 pounds would be 18 to 24 % of the breaking strength of the wire.  Based on this, I set my goal tension at 1,500 pounds or 18% of the breaking strength of the wire. As I said, the backstay splits at 12 feet from the stern.  This point is too high for me to measure above the split.  So I have to take my readings below the split on each leg.  But that means accounting for the tension of both legs.  The angle of the split is approximately 25 degrees.  If the angle was at 45 degrees then each leg would just need to be set at 50% of the desired tension.  Using another SWAG, I estimated that each leg needs to be set at 60% of the desired tension.  That would be 900 pounds.

The upper shrouds are 5/16″ wire.  Based on my research I wanted these to be set at 15% of the breaking strength.  The intermediate shrouds are 1/4″ wire and should be set at the 10% of breaking strength. The lower shrouds set the prebend and are 1/4″ wire.  Since you want a 0.5-1 inch prebend you will have more tension on the forward lower shrouds then the aft lower shrouds. Neither should be more than 15% or less than 8% of the breaking strength.

Based on all of the above, here are my goal tension settings:

  • Backstays: 900 pounds, 10 on PT-3 Loos Gauge
  • Upper Shrouds: 1,875 pounds, 29 on PT-3 Loos Gauge
  • Intermediate Shrouds: 820 pounds, 9 on PT-3 Loos Gauge
  • Forward Lower Shrouds: 1,230 pounds, 13 on PT-3 Loos Gauge
  • Aft Lower Shrouds: 656 pounds, 6 on PT-3 Loos Gauge

In an ideal world these tensions would be equal on the port and starboard sides of the boat but that would not likely be the case since the boat isn’t laid out exactly symmetrical.

First thing I did was loosen all of the shrouds and backstays to hand tight.  I measured to two points on the toe rail that was the same distance from the mast base.  I then used the main halyard to measure if the mast was straight.  It wasn’t so I straightened the mast by adjust the upper and intermediate shrouds.  I sighted up the mast to make sure it looked correct.

Then I tensioned the backstays until I got to the desired rake.  But guess what? The turnbuckles bottomed out and I could only get about 3-4 inches of rake.  I measured the rake using the main halyard with some weight hanging from it (I used a water bottle).  The backstay is too long.  The easiest way to fix this is to cut about 6 inches off of the backstay above the split and use a Sta-Lok Eye Fitting to terminate the wire. But that will have to weight for another day.  I was able to get to 3-4 inches of rake and an 8.5 on the Loos gauge (around 800 pounds).  While not being perfect it would work.

Next I tensioned the forward lower shrouds.  At 12 on the Loos gauge I had about 1/2 inch of prebend.  I measure the prebend by attaching the main halyard to the goose neck for the boom and putting tension on it. I then made a visual estimate of the bow towards the bow at the point where the forward lower shrouds attached. I then took up the aft lower shrouds until they read 7 on the Loos gauge.

I then alternated port and starboard side, making a couple of turns on both the upper shrouds and the intermediate shrouds.  I kept checking that the mast was straight with the main halyard. Eventually I got to a point where I couldn’t tension the upper shrouds any more.  The brass turnbuckles were just warping under the pressure and I didn’t feel comfortable.  Both the port and the starboard were reading 25 on the Loos gauge.  But when I sighted up the mast and measure it with the main halyard it appeared that there was a slight bend to port. So I loosened the port a half turn at a time until it was straight.

The next step in tuning is to see how it performs under sail.  I simulated this at the dock.  When sailing in 10-15 knots of wind we are healing between 10-15 degrees.  So I attached the main halyard to a cleat at the dock and cranked it in until we were healing 10 degrees.  I then went and checked the “leeward” side.  Only the intermediate shrouds felt loose.  So I took up two full turns on it.  I repeated the process on the other side and got the same result.

I pinned the turnbuckles and I am ready to sail. The whole rig feels a lot tighter and more secure than it did prior to the tuning.  I had one of my sailing buddies that races a lot and has been crew on many delivers over and he took a look.  He was amazed at how straight I got the mast port to starboard.  He said he would feel very comfortable sailing on our boat offshore.

Advertisements


4 Comments

Running Rigging

So I tried to farm this research and work out to an expert rigger, but after going back and forth with him for over 4 months and still not having anything to show for it I gave up. I fired him a few weeks back and started doing my own research.

All of the running rigging with the exception of the furling line on Smitty is original.  That makes it 14 years old and it is showing it’s age.  There are numerous locations with noticeable dry rot and some chafing. Most of the white line now looks gray with the exception of the areas that are either always in the mast or in the organization bags in the cockpit.

We also will get a little bit of bagging in the base of the sail.  I had a sailmaker look over the sail last year and they said it was in near new shape (not a surprise, the previous owner only sailed the boat a couple of times a season and the sail still had creases when we bought the boat). Thier recommendation was that the halyard had too much stretch and that we should add a cunningham.

One of the good things about owning a Catalina is that they have very good owners manuals.  For the C310 they have a page in the manual that gives you all of the diameters and lengths of line you need for the running rigging.

Rigging Specs

So with that in mind I started looking at different types of lines.  I started with Catalina Direct.  They had various halyards and sheets for sale.  For the halyards they use a 3/8″ Dyneema core line with a polyester cover that is supposed to provide an extremely low stretch halyard for about $1.85 per foot. For sheets they use a 7/16″ polyester core with a dacron polyester cover that is supposed to provide a low stretch sheet for about $1.00 per foot.  After doing a little research I decided that the lines offered by Catalina Direct were good for day sailing with the occasional coastal cruising but that we should upgrade to something better for Caribbean cruise.

I next looked at Samson Ropes, they are sold by Defender and our friends Pam & Chris have used these lines on their Catalina 30.  The Sampson XLS Extra is a Dyneema core line with a polyester cover; in 3/8″ line it has a breaking strength of 5,100 pounds and an elastic elongation of 0.8% at 20% load at a cost of $1.39 per foot.  This would be a good upgrade for the halyards.  The Sampson XLS is a polyester core line with a polyester cover; in 7/16″ line it has a breaking strength of 5,800 pounds and an elastic elongation of 2.2% at 20% load at a cost of $0.99 per foot.

I also looked at New England Ropes, they are sold by West Marine, Defender and a couple of other local companies.  They were recommended by the rigger I tried to higher to do this work.  The New England Ropes Sta-Set X is a polyester core line with a polyester cover.  However they use a patented parallel fiber core that is supposed to provide superior strength and lower stretch than Dyneema.  In 3/8″ line it has a breaking strength of 5,300 pounds and an elastic elongation of 0.7% at 20% load at a cost of $1.65 per foot at West Marine.  Again, this would be a good upgrade for the halyards.  The New England Ropes Sta-Set is a polyester core line with a polyester cover; in 7/16″ line it has a breaking strength of 7,100 pounds and an elastic elongation of 2% at 20% load at a cost of $1.80 per foot at West Marine.

After weighing these options and reading some reviews on the typical boating forums, I decided to go with New England Ropes. I was able to get the lines much cheaper than West Marine from a shop called Rigging Only located down in Fairhaven, Massachusetts.  I ended up paying $0.88 per foot for the 3/8″ Sta-Set X and $1.08 per foot for the 7/16″ Sta-Set.

The next thing we had to figure out was how to connect the line to the shackles.  A common approach is to splice an eye in the end of the line.  This gives you close to 100% of the strength of the line.  But one downside is that splices can make the line thicker for about 6 inches at the splice.  This can get jammed in the sheaves at the masthead.  Another issue is that is more difficult to periodically end-for-end the line to prolong the life of the line.

Another option is to tie the shackles to the line.  Knots reduce the strength of the line but with the high breaking strength of the Sta-Set X I wasn’t really concerned.  I looked at 3 knots that seemed to be commonly used by cruisers as follows:

  • The bowline: commonly known knot, reduces the line strength by 40-60%, can be tied in about a 4″ length on the size lines for the halyards; can easily be untied; pulls straight on the headboard;
  • The figure 8: commonly known knot, reduces the line strength by only 20%, can be tied in about a 1.5″ length on the size lines for the halyards; can easily be untied; can pull off center on the headboard, and;
  • The buntline hitch: new knot for us to learn, reduces the line strength by 25-50%, can be tied in about a 2″ length on the size lines for the halyards; cannot easily be untied; pulls straight on the headboard.

We decided to go with the tying a buntline hitch onto the shackles.  This knot is relatively easy, can be tied close to the shackles and doesn’t reduce the strength of the line too bad.  We might have to cut the knot off when we go end-for-end but that’s not a big deal since we would want to get rid of that portion of the line anyways.

To learn the knot I went to Animated Knots by Grog. After a couple of test knots I was good to go.

To run the new halyards I put them end-to-end with the old line.  I then used some waxed polyester whipping twine and a sailmaker’s needle to connect the two lines.  You don’t have to do much, just 4-6 loops through both lines will keep them together without adding much thickness so they can pull through the sheaves easily.  It took me about an hour to replace the 4 halyards on the boat.

Let’s talk about the 4 halyards for a minute.  Smitty has those nice, fancy labels on all of her clutches that label the lines.  According to those we have a boom topping lift, a main halyard, a jib halyard and a spinnaker halyard.  The boom topping lift and the main halyard run up to the two sheaves on the stern side of the mast and the jib and spinnaker halyards run up to the two sheaves on the bow side of the mast.  Technically the “spinnaker” halyard is just another jib halyard as spinnaker halyards on masthead sloops would go through a block that is outside of the mast to allow for the proper angle of approach from a spinnaker.  But we don’t have any plans to fly a spinnaker and the primary purpose of this line will be to lift the dingy so it’s not a big deal for us.

Also, we don’t technically need a topping lift.  We have a rigid boom vang that supports the mast without the topping lift.  The primary purpose of the topping lift on our boat is to hold the Dutchman system for the mainsail. An upgrade suggested by the rigger before I fired him was to replace the small diameter topping lift with the same line as the main halyard.  This would give us a backup halyard incase anything happened with the primary main halyard.

Once all of the halyards were replaced, we bent on the sails.  Smitty finally looks like a sailboat again!

We still have some of the other running rigging to replace.  Also, I want to give the mast a good tuning before our trip to Provincetown for July 4th.  But it’s nice to be a sailboat again.


6 Comments

Sailing a Modern Hull

Last weekend we were at a friends yacht club for some nautical bingo.  Fun night and we won an eco air horn and spare dockline.

During the evening I got to talking to a prospective member of the club.  He has been sailing a Catalina 30 out of a nearby marina for 8 -10 years and was trying to become a member of the club and purchase a bigger boat.  He was looking at boats similar to the Catalina 36.  After talking to him about what he was looking for in a bigger boat (i.e. larger master berth, more room for short term guests, bigger cockpit, bigger head, etc.) I suggested he should look at the Catalina 350 as many of the layout aspects may be better for his intended use.  He responded that he had ruled out the C350 because he heard it didn’t point or track well.  Ugh!

This is one of those things that you hear and that is perpetuated by the internet that drives me crazy.  How you sail a boat has a lot to do with the hull shape, the rig and the conditions.  You just simply can’t sail a Catalina 310 the same way you would sail a 1970s Cape Dory or a Lyle Hess Bristol Channel Cutter. Understanding the hull’s stability curve is paramount to sailing the boat efficiently.  This requires having some basic knowledge about form stability vs. overall stability vs. dynamic stability.  In this day and age of computer designed boats and boat designers willing to help the public learn it’s never been easier to get this general understanding.  Here are some of my favorites:

Bray Yacht Design, Stability – What Is It and How Does it Work?:

Stability is the ability of a vessel to return to a previous position. Positive stability would then be to return to upright and negative stability would be to overturn. Stability in it’s most basic form is the relationship between the center of all floatation in your hull (center of buoyancy, or CB) and the center of all weight (vertical center of gravity, or VCG). In other words, the downward pull of Gravity and the uplifting force of Buoyancy. These are the primary characters in this scene and all others play minor roles. Once you understand how their relationship works, understanding stability becomes a simple matter.

M.B. Marsh Marine Design, Understanding Monohull Sailboat Stability Curves:

midship_sections

Righting moment with KG's scaled for hull loading

Righting moment with KG’s scaled for hull loading

  • Hull A, the narrow one, will have a hard time flying much sail. She’ll heel way over in a breeze. But she can’t get stuck upside down.

  • Hull B, a moderately slender cruising shape, also can’t get stuck upside down- her AVS is 170 degrees. Her extra beam causes the centre of buoyancy to move farther to leeward when she heels, so she has more initial / form stability than hull A and can carry more sail.

  • Hull C, which is typical of modern cruising yachts, has over twice the sail-carrying power of the slender hull A. She’ll heel less, and since her midship section is much larger, she’ll have more space for accommodations. The penalty is an AVS of 130 degrees. That’s high enough that she can’t be knocked down by wind alone, but wind plus a breaking wave- such as in a broach situation– could leave the boat upside down until a sufficiently large wave comes along.

  • Hull D, the broad-beamed flyer, can hoist more than three times the sail of hull A at the same angle of heel. She’ll be quite a sight on the race course with all that canvas flying. Her maximum righting moment, though, is only 37% more than hull A’s, which leaves less of a margin for error- hull D is more likely to get caught with too much sail up, and will reach zero stability at a lower angle of heel. If she does go over, she has considerable negative stability, making it unlikely that she’ll get back upright.

Wavetrain blog, Modern Sailboat Design: Form Stability:

formstabl.01

 

 

 

formstabl.02

 

Stiff boats with good form stability in one sense are more comfortable, especially for novice sailors, than boats that heel easily. In another sense, however, they can be very uncomfortable. Though they are rolled to less severe angles, they snap back from those lesser angles more quickly and abruptly than boats with less form stability that are rolled to greater angles. The resulting motion can seem jerky and violent, and this is reflected in a boat’s motion-comfort ratio. This quick motion, combined with the tendency of a flat-bottomed boat to pound in a steep head sea, may lead some to conclude that there can be such a thing as too much form stability.

The most important thing to remember about form stability is that it does not translate into ultimate stability. A sailboat’s hull form can help it resist heeling up to a point, but past that point all bets are off. A boat that depends too much on form stability to stay upright will be capable of supporting an enormous sail plan in moderate conditions, but when caught in a sudden squall with all its sail up, it can be laid over and capsized very quickly.

Ted Brewer Presents a Primer on Yacht Design:

The terms and ratios that follow are used by all yacht designers so it’s a good idea to have an understanding of them if you are considering buying a boat, or having a custom design created (of a classical style, of course!).

You may need to work out some of the ratios for the boats you are considering for purchase from the available information but the formulas are simple and can be handled by an inexpensive scientific calculator. The one I use in my design business is a Sharp EL-520, almost old enough to vote, and cost less than $25 new, too many years ago.

Robert Perry (my personal favorite designer), Keel Design According to Perry on the Sail Far Live Free blog:

I have designed a series of full keel boats (Baba 30, Baba 35, Baba 40, Tashiba 31, Tashiba 36) and all of these boats sail quite well. But I have pulled the leading edge of the “full” keel aft and tried to give it a reasonable leading edge in terms of shape. Some people call these designs “modified full keels”. That’s OK but those labels can be pretty nebulous. Probably my biggest complaint with full keel designs is that they seldom if ever back up well under power. They also add a lot of wetted surface and that can kill light air performance. Plus, they are so long in chord that if you give them a good efficient foil say with a thickness ratio of 10% (width of the keel compared to the chord length) you will end up with a fat keel that adds too much displacement to the boat. And the funny thing is, and it’s not intuitive, all that keel volume is on the wrong side of the righting arm when the boat heels over. So technically a big full keel can reduce your righting moment.  Go ahead and love your crab crusher full keel boat but don’t try to justify the design on technical terms. Some traditional full keel designs have a lot of subjective, aesthetic appeal. That’s good enough reason to love your boat.

We don’t have to guess anymore about keels and draft. I use a Velocity Prediction Program (VPP) to analyze my hulls and keels. I can try various keels and drafts and pick the one that gives me the best combination of performance results. We reduced the draft on CATTARI 6” after doing a series of VPP runs.

I included this last bit from Robert Perry to highlight a point I often make.  Too often we fall in love with a look of a boat or how salty we think it makes us to have certain aspects of a design.  But seldom do most people actually understand what that feature actually does for performance.  Also, I often get chastised from old, salty types for bringing up that boats designed by computers have advantages over older designs done by hand.

Several weeks ago I came across this blog post: How to Sail a Morgan Out Island 416.  Many of the characteristics described in this post are similar for modern cruising boats like the Catalina 310 and Catalina 350.

All yachts are a compromise. As such, each design has its strengths and weaknesses; the Out Island 41 is no exception. She is very beamy to allow for more living space below and more room to enjoy the pleasures of being on deck. In addition, her draft was kept relatively shallow so as to allow her owners to enjoy many anchorages and gunk holes. These can be enjoyed only by dinghy when sailing deeper draft yachts. As a beamy, shallow draft yacht, she must be handled on some points of sail in a slightly different way than a deeper draft yacht with less beam. The most prominent distinction exists on the wind and close reaching. Sail trim on both these points of sail is critical for optimum performance.

This post goes on to describe some specific techniques for different points of sail and conditions.  Almost all of these tips hold true for our Catalina 310 and some other modern designs like Jeanneaus that we have sailed.

The way I often describe it to people is you have to sail a modern cruising boat almost like a catamaran.  My Catalina wants to sail flat footed.  We typically stay between 10-15 degrees of heel.  If we are heeling over 20 degrees we can see a noticeable reduction in our speed.  Compare that to a Pacific Seacraft 36 that feels like it will heel to 25 degrees with the slightest breeze but can’t get pushed over 40 degrees in gale force winds. This gets back to the form stability vs. overall stability discussed above; it’s like comparing Hull A (Pacific Seacraft) and Hull C (Catalina) in the article from  M.B. Marsh Marine Design.

If you sail a beamy, modern hull over heeled it will not point well. The keel is designed to stay deep in the water and not be up closer to the surface.  With the keel up high, you will have sideslip and your will not point well.

So REEF!  Reefing is not a sign of defeat or the sign of a beginning sailor.  On most points of sail we need to reef at around 18 knots or we lose significant speed.  The good thing is that Catalina designed our boat to make this easy.  We have factory installed, single line, slab reefing.  This means all you need to do to reef the main is ease off the sheet until luffing, release the main halyard and ease it down while taking up the reef line, once the reef point is down to the boom lock it in and retention the main halyard.  All of this can be accomplished from the cockpit in under a minute if you are well practiced.

There are many other small pointers such as sail trim, lead positions, etc. but the article on sailing a Morgan Out Island already does a great job of listing these so I won’t repeat them here.

In my opinion there are very few bad boats.  Boats are designed for a purpose and a price point.  Add to that some aesthetic characteristics.  To balance all of these you need to make compromises.  I always say that a boat is a series of compromises and it’s finding the balance of these that best fit your wants and needs that will make for a good match between the boat and owner.


Leave a comment

Two Comfort/Entertainment Upgrades

We completed two quick upgrades this weekend.

First, was putting on the Lewmar folding steering wheel we got at the Defender annual sale.  They are normally about $750 but we got it for $450 on a closeout sale.

IMG_0959

This is a great comfort upgrade and makes the cockpit feel even bigger.  I still have to re-install the autopilot. The OEM wheel had 12mm spokes and the new wheel has 16mm spokes.  So I have to order new clamps for the autopilot ($20 from Defender) and possibly drill and tap the drive wheel.

The other upgrade was we added a new stereo.  I had been pining over our friend Stu’s new stereo last year because he had wired remotes at the helm and in the cockpit (he has a power boat with a raised helm deck).  Our stereo had a remote, but it was infra-red and you had to be within sight of the stereo for it to work.

I was looking at the Fusion with the iPod/iPhone dock.  But that’s a $500 unit plus about a $100 for the remote.  Not exactly a budget friendly item.  I was looking at this unit during the boat show and a salesman from West Marine told me I should check out their new radio.  It comes with two remotes; one is infra-red but the other is radio frequency.  That means it doesn’t need line of sight and it was supposed to have a 30 foot range.  I watched West Marine for it to go on sale and picked up the radio for $169.

Here are the installed pictures.

IMG_0971

IMG_0969

RF module.

IMG_0968

Wiring bus for speakers and power.

The first unit had a broken LCD screen.  The cell in the middle of the screen didn’t display correctly.  So I brought just the face plate back to West Marine and we tried it on their display unit. Same thing.  So they swapped out the face plate and when I put that on it worked perfect.

It is iPhone/iPod compatible.  Using the USB cord you can charge and control your iPhone.  You can even play Pandora and podcasts over the system from your iPhone.  The RF remote only does source, fast forward, rewind, volume and mute.  The IR remote can actually search your iPhone and display on the LCD screen.  So your playlists are fully playable, as is selecting by artist, genera, album, etc.

The RF remote is great.  It easily worked at the helm and even worked about 10-15 feet up the dock.  It’s water proof and based on the range, I could be swimming or hanging on a float behind the boat and be able to work the remote.

The installation is a little over kill as far as the bus bar.  I suppose I could have just used butt connectors like the PO did, but after all of the electrical system work it just didn’t feel right.  So that was about another $20 on the installation.

Last night we did have a little problem.  While watching TV every now and then there is a cross over in signals.  The radio would turn on while trying to change the TV channel.  I will have to do some more reasearch on this.