Regatta Tech Sessions - a summary
Courtesy of Jeff Hare
At this year's regatta, Dick organized tech sessions by:
* Mark Felgenhauer at Garhauer Marine,
* A technical guy from Lewmar,
* A Yanmar technical representative
* Some riggers demonstrating how to tension and adjust the mast rigging on a C320.
This is about all I remember from those sessions. If you attended and have things to add or corrections to make, please feel free to note them and make corrections. I'd like to post as much information from the tech sessions as possible on the website, but since I didn't take any written notes, I probably forgot about lots of things that were discussed. I may also have made some mistakes below in trying to write this email, so "have at it!".
GARHAUER:
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The session with Garhauer was an interesting opportunity to see the new products they've introduces for the C320, and ask tech questions about applications. One of the most interesting new products is the replacement
LEWMAR:
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The Lewmar rep, discussed how to disassemble the side hatches, stop leaks and adjust the latch mechanisms. He discussed the 4 types of side hatches used on the C320, and showed the new Stainless Steel framed replacement hatch used on the current and future C320s. He also indicated that Lewmar now makes all the hatches on the C320, so at some point the forward hatch went from being a Bomar, to a Lewmar. It would be interesting to know when this change occurred.
My observations: (from memory)
There are two shapes for the standard side hatches. Rectangular Ends & Rounded Ends.
As a common note, he indicated that replacement inside rubber seals on the side hatches are available and replaceable if they're damaged and leak, but keeping them clean and having the closing tension properly adjusted (where possible) should eliminate leaking through this seal.
Rectangular End side hatches:
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Used on the Earlier C320's (prior to ~2000??), and have the twist style of hatch closure.
There are two styles of outside frame for these. The older style has a horizontal seam in the center of each end, and those that have a single vertical seam at the bottom. The older styles were prone to the sealant in
the seams drying out and allowing water to enter the hatch frame, and leak inside. He had a procedure that would help eliminate or reduce that leakage. The newer version of the rectangular hatch had a vertical seam on
the bottom and was far less prone to leaking. But he said, to pull the inner trim ring and if you see water in there after a rain, then the rubber in the outer seal is probably leaking. Someone who took notes, may have
more details here.
He indicated that there were a couple versions of the twist lock closures on the rectangular frames. Ones that had the catches welded, and others that had the catches screwed in. He had a procedure that would let you adjust the closing tension here.
Rounded End side hatches:
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Used on the newer (post ~2000-ish?) C320s and have the flip up/down hatch closures.
Lewmar has made a few different versions of these side hatches, with the differences being mostly in the appearance of the finish on the aluminum outside trim.
The newest version has a SS outside trim ring and looks very nice. The rounded end hatches can be directly replaced with the current polished Stainless Steel side hatches since the sizes and hull opening requirements
are identical. They are not a direct replacement for the squared end side hatches however. I forgot to ask about whether they have better side screens on the new SS hatches.
YANMAR:
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He mentioned quite a few things. Some of them I remember, most of them I don't. :)
* Again, he reiterated that regardless of which prop you have, the engine needs to be able to reach 3600 RPM under load or the prop is overpitched.
* He indicated that a 2 micron filter was a good idea and that the engine and pump has absolutely no difficulty with this fine a filter. I mentioned (after his presentation was over) the discussions this list has
had and the concerns some raised about not getting a good enough flow with 2u filters. He said that the engine is efficient and doesn't need to move lots of fuel, so fuel starvation isn't going to happen just because you use a 2u filter. He indicated that the difference in fuel flow through 2 and 10 micron filters is really quite minimal. He indicated that the finer filter is better for the injectors and that 2micron is stock for newer
yanmars anyway. Filter size does matter in really cold (below freezing) weather where diesel gelling issues are possible. But I'm tucked in at home beside the fireplace in those conditions anyway. :)
* He discussed the differences in the 3YM vs. 3GM. Mainly that the seawater impeller is easier to change.
* He indicated that we should CHANGE our ANTIFREEZE to the DexCool variety. He said yanmar found that the Green (and others?) were possibly the cause of corrosion in the aluminum parts of the heat exchanger. Yanmar is using DexCool in these engines exclusively now. (Please correct me if I missed something here). We discussed flushing it out, and he said that we should try to get as much out as possible, but not to worry about small amounts left in there, that small amounts mixing wouldn't be harmful.
* He mentioned that the impeller should be checked every year, and replaced every ?2?. (I forgot his exact answer, but he indicated that look for wear and cracking.)
* He cleared up the "impeller mystery" between the European and Japanese Yanmars. He said that there are 2 different pump manufacturers:Johnson, and Yanmar. The Yanmar pump, needs an impeller with the keyway and a paper gasket. The Johnson pump uses a rubber O-Ring and has a slotted shaft that accepts an impeller with a screw through the center of the hole in the impeller. He indicated that the Japanese Yanmars typically (but not always) used the Yanmar pump, while the European Yanmars typically used the Johnson pump.
If you have an engine with the JOHNSON PUMP (it says so right on the back plate), you can use the Johnson impeller kit which comes with the oring, some unneeded paper washers and the impeller. Yanmar also sells this impeller, but sells the o-ring separately (and is probably more $$). He recommends just getting the Johnson kit if you have the johnson pump.
If you have an engine with the YANMAR PUMP, (may say yanmar, but doesn't say Johnson :), then you probably have to buy the impeller through Yanmar or some other OEM supplier. It needs the paper washer.
RIGGING:
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The riggers discussed how to tune the rig. They indicated that the cap shrouds should be tensioned to no more than 12% breaking strength.
They demonstrated proper use of the Pro version of the Loos gauge.
They recommend the use of Boshield T9 spray on the turnbuckles to penetrate, lube and seal out moisture. DON'T use this on turning blocks however because it leaves a waxy buildup behind. Sailkote or other dry lubes are preferred for turning/sliding blocks.
They spent a considerable amount of time discussing the concept of pre-bend in the mast. (my interpretation and words follow here, so correct me if I incorrectly conveyed what they said)
Pre-bend is a slight bend in the mast arching aft. Even for a furling main! The reason is that when the mast is perfectly straight in column, the middle will tend to pump (wiggle fore and aft) which will cause damaging fatigue stresses on the mast.
They indicated that we absolutely want to ensure that our mast has some pre-bend. This is accomplished by ensuring that the FORWARD LOWERS are tensioned properly and tighter than the AFT LOWERS, and that the backstay is not too loose. This is to pull the middle section of the mast slightly forward and introduce some bend.
An interesting side-note: While at the Marina Del Ray regatta a couple years back, I noticed that most of the C320s there had very loose (almost floppy) forward lower stays.
An observation on their techniques: If you've seen Brion Toss's video on rig tuning, he has a far superior technique for adjusting the turn-buckles which puts less stress on the turnbuckle and is easier.
Procedurally, they said, put enough tension on the cap stays (highest one) to keep the mast from falling down. Then generally work from the bottom up, side to side until the shrouds are up to tension.
There was a lot more, but it seemed obvious to me, so I don't recall specifically what they said. Sorry!