My 2 GM 20-F Yanmar
is in the "under the companionway steps" position. I think this is better, especially for the SR34, because the old "under cockpit" spaces drawn were for the long narrow Atomic 4s, of decades past. It is really tight in there for short fat little diesels. This is IF one was starting over anyway of coarse... Roy's beautiful installation may be an exception, as there is so much more room from the get go on a 40. If you haven't been on a 40, they're HUGE!
I have, and still like, my PSS shaft seal. The non vented model I started with was problematic, so I switched to the irrigated version, which is the ONLY way to go in my view. (Drawing water from the engine's up turned loop)... This way the bearing at the shaft log's end gets irrigated a bit, lessening debris and wear. If one has no bearing in the log at all, just vented may be OK, but if it was me, I'd still go with a properly irrigated set up.
BTW... My PSS rotor slid up the shaft once, (when we were on a date ashore), partially flooding the bilge
of the main hull. If I hadn't had a trimaran
... The grub screws just barely grab the hard Aquamet 22 shaft! It can never happen again. Now I back up the rotor with a doughnut zinc, with a "small" bead of caulk at contact points between them. (It is important to JUST make contact, and not push the rotor out of perpendicular to the shaft). I still like the PSS, and trust it... WITH a back up to keep the rotor from moving.
The CV joint with thrust bearing goes a long way toward extending the lifespan of transmission
bearings, and engine feet. (None of the thrust goes on the engine at all). It also protects the installation if you grab a crab pot, AND since the shaft only spins, and no longer shakes with the engine, the stern tube's cutlass bearing last longer, and the PSS seal works better. It is a pricey little jewel, but over decades, more than pays its way in reliability
Roy, your installation sounds and looks stellar. 8 KNOTS, EVEN IN A SEAWAY... DAMN!!!
My little 2 gm 20, (really 18 HP MAX), "just" pushes us at 6 knots, running our regular 2,900 RPMs, at the same consumption
as you, 1/2 gal per hour. If there is a 20 knot head
wind, we go in the low 5s, and with 25+ knots of wind and a really nasty seaway, in the 4s. Luckily we sail most of the time! It would be nice to have the bigger 30 HP, but I would loose too much space to go that route
, (with the engine still in the middle), and I like the access I have there... Guess I will stay with the runt of an engine that I have.
Phantom Boatwork... On tips for glassing your rudder / skeg. First, you need a lot of homemade BIAS CUT glass tapes, in varying widths 2,3,4,5,inches wide, that are cut at a diagonal to the roll of 10 oz fabric
, (With a pizza cutter
knife). With these, ALL of the fibers go across the joint, vs just half of them. Also, they will compound bend around radii, even on a curve.
I would glass the faces of the foils about 1/8" thick, MIN! That's a number of layers. I don't remember... 4 or 5 at least. This is NO PLACE to save weight! On all of the edges, I used those bias tapes to glass to about 3/8" thick. Especially on the leading edges and lower collision
with the bottom "nose". On the aft rudder edge, (sans trim tab), we let the glass run back about 3/4" past the wood, which was SHARP. Then doing the other side the same, so the aft edge is all glass, and only about 1/8" thick.
After shaping to perfection, with NO hollows or flat spots, (detected by rolling a straight edge around the foil), I put on 6 or more top coats of epoxy
, so that after years of future bottom paint removal
, I still never expose any glass fiber.
I don't know what John drew on your boat
, but the best rudder / skeg arrangement I ever saw, was the "no metal" version on my previous SC 28. This had only one underwater metal part... a 3 to 4' long, single
316 grade SS rod. Since the polypropylene fabric/epoxy bearings were wrapped around the waxed rod as a mold
, the fit was a PERFECT '0" tolerance fit. If heavily glassed... It was vastly superior to the clunky nuts & bolts and massive SS gudgeons & pintles, found on our Searunners. These are hard to build, paint
, clean, and maintain in every way.
The trim tab idea is fine IF you will have a wind vane
, and really need one, BUT tris with a skeg / rudder and CB, track sooo well, and staying level, hunt soo little, that a standard wheel autopilot
like the Autohelm
, (Ray Marine
4,000), can handle the loads just fine, while just sipping amps. On a monohull
, you would need a really consumptive down below autopilot
I have tens of thousands of miles on our wheel
pilot, and meant to carry a spare, but never got around to it. If it was me, I'd skip the "trim tab to a small tiller pilot" idea, and use a wheel pilot. Having said that, IF you need the trim tab for a wind unit anyway, why not have both a wheel pilot and a tiller pilot. (You will find that the wheel pilot works a LOT better in a seaway though).
If you have built that nifty "all composite" rudder to skeg connection, however, I would definitely not muck up the concept
by sticking metal under water that could otherwise be avoided. Just a thought...
LOVE that table! What a beauty. That is on my list. I want a longer, lighter, round ended table.
Best to all...