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Roy M · 06-05-2011, 17:20

Searunners, built to plans, have exceptionally long prop shafts, especially for the 40. The trick is to keep them well-aligned (0.003" max), use a smooth running engine (mine is a Yanmar 3GM30), use pillar block bearings at each frame (39"), and use NO flex couplings (which seem to aggravate the problem of vibration). My old Volvo MD2B used to make the coffee cup dance on the sterncastle table, directly above the shaft strut. That was a 500 pound lump of massive spinning flywheel and two cylinders fighting for supremacy. The Yanmar is a fine sewing machine that weighs in at half the Volvo, has more power, and is so quiet that it can be sometimes overlooked. The folding prop is an 18" Martec Mark III that only lacks in reverse gear what it gains when folded and sailing through a thick kelp bed.

Aligning an engine is not a black art. Disconnect the shaft coupling from the engine flange and spin it with one hand. If it is tight, it's going to heat up the shaft packing, or wear out the cutlass bearing in the strut. These are areas that need to be PERFECTLY aligned to the prop shaft, as well as the intermediate pillar block bearing(s). If you can't spin the shaft easily, then something isn't right before you even get to the engine alignment. You may need to haul the boat to correct this, but the rewards will be ample.

The engine alignment is relatively simple, IN THEORY, but the execution may seem impossible. Think of it this way: the shaft fits square with the shaft coupling because it's machined that way (and should have been checked for this at original installation). The engine coupling damn well better be square because you paid a lot of money for that assumption. Therefore, theoretically, they should mate together and be perfectly linear. The problem of the real world is that engine beds are not always perfect, the motor mounts may not be well secured to the engine bed rails, motor mounts that have been abused by misalignment begin to break down prematurely and cease to reduce the jumping of the engine as it seeks to escape from its work assignment. And, my personal favorite for irritations (and my responsibility as the builder of the engine's residence space), the access to each and every hold-down bolt and adjusting nut on the engine. In my own (and most of the other Browns) the engine sits pretty near to the port side of the centerboard trunk, limiting easy access. I have to remove my engine exhaust hose to get to the aft, inboard motor mount. Since one doesn't have to align the engine, all that often, it's a relatively small irritation. The other problem is that the engine mount adjustment nuts are then also close to the trunk, as well as the engine. I handled that by buying an extra wrench of the size needed, then cutting it in half to allow me to swing it more effectively in a confined space (one more special tool for the inventory).

The process of alignment requires a couple cups of coffee, a kind assistant to hand you tools and check the alignment progress with a feeler gauge (because you are probably up in the forward cabin and don't want to climb up and out with each twist of the wrench), kneepads for the older sailors, and some degree of patience. Start by pulling the coupling up tight to the engine flange, using a couple bolts and nuts to get first contact. Measure all around the edges of the two mating surfaces with the feeler gauge, set at 0.003". Make a drawing to help visualize the situation. Put your palms together to simulate the situation you face. One part of the two flanges is touching, the rest are not. What do you need to do to bring everybody together iin mated bliss? Play with your hands some more to see what combination of raising and lowering of the engine mount adjusting nuts will improve the situation. Maybe, it's something more than this that is needed: the engine may simply not be twisted enough in one direction or another to bring the flanges together. That's why the engine mounts have that little slotted opening at one (or both) ends where they get bolted into the engine bed mounts. You may have to loosen the attachment bolts (or lag screws) to allow you to manhandle the engine sideways, one direction or another, to improve your options. You can use a short two by four or a crowbar to give you purchase. In some cases, you may have to take some weight off the engine by hoisting it a tad (my boat has a bronze inspection plate in the cockpit sole that allows me to pass the halyard down for a "skyhook", or to use a chainhoist.

Any ways, it is a dance of raising and lowering, perhaps some lateral shifting, that eventually achieves a near perfect mateing of all but one quarter of the shaft coupling so tightly that the feeler gauge can't get in there. If you have more coffee and time and patience, you may improve the fit. If not, three thousandths of an inch is better than most of the boats around you are enjoying. Spin the shaft and double check the gap, then bolt up the flanges securely. Start the engine, check the spring lines to the dock, and put it in gear, bringing the speed up to approaching your normal cruising RPMs. Put your ear to a bulkhead (like a doctor uses his stethoscope) and listen to the noises you can hear. Feel the vibrations on your cheek. Check it in several places on the boat. Put your hand on the shaft gland to see if it is whipping or heating up. You should be very happy with the consequences. Shut down the motor and check the security of the flange bolts. If you have an abundance of time, slack the bolts again and double check the misalignment. It ought to remain the same, otherwise, someone forgot to tighten the bolts or screws on the engine mounts. Personally, that may or may not have ever happened to me, surely not, at least not intentionally.

My coffee cup now only has tiny concentric ripples in it when the engine is running.

PhantomBoatwork · 07-05-2011, 06:02

Ah, excellent forum and excellent post! Can I pick a few brains? This is for my CC 44 center cockpit tri by John Marples. I have an M50 Universal diesel - four cylinder, a Martec folding prop and allowances for an 1 1/8 shaft between the two. It isn't installed yet, as the motor is sitting in my garage and the prop is in my attic. I "bore sighted" the shaft tube with a laser and drilled the shaft hole through the bulkheads to the engine compartment. I also have two flange mounted bearings for the bulkheads. What I need to know is whether a PSS shaft seal at the stern tube will give enough support at the inboard end, or do I need another bearing. The stern tube will have a cutless bearing about 40 inches away. Also, does anyone have insights for the engine supports? I think John suggestged 2x6 with threaded rods bonded in, butr I was thinking of aluminum angle bolted to maybe 4x6 which could be epoxied to the bulkheads. What have you lother guys done. My engine and tranny is about 545 lbs. I reversed the centerboard trunk when I built it so the exhaust manifold is outboard, but I have never installed a marine diesel and I want to get it right. Any help out there?

Rann · 07-05-2011, 08:43

My shaft for the Searunner 34 is also long, but not as long as Roy's in his SR-40. I helped remove and re-install a shaft in a 40 footer, and boy-oh-boy, is that a long shaft! We did it in the water with floats supporting the shaft keeping it just buoyant. We didn't want to dive for it in 50 feet of murky water and a muddy bottom.

Those pillow block bearings are essential for such a long drive-line. Alignment, as Roy so aptly described in his post, is critical to smooth running. His advice is spot on.

PhantomBoatwork · 07-05-2011, 08:55

Would having the shaft made in two pieces with a shaft coupling/flange in the middle be a good idea? I can't imaging trying to maintain a precision shaft absolutely straight while cramming it in from the stern through a whole raft of bearings.

Rann · 07-05-2011, 09:48

The big issue with a coupling and shorter shaft is including a thrust bearing in the coupling. The Aqua-Drive system is such an arrangement. The thrust bearing must be mounted on a major part of the boat such as a main bulkhead. Thus the prop is driving the boat via that bulkhead instead of pushing the motor. I have just such an idea for my 34. I had a friend make me up a unit I plan to mount to the aft main bulkhead. It is a bearing unit with a U joint coupling common to U.. vehicles. The bearings are within a housing with oil seals and a zerk fitting for maintaining lubrication of the bearings. Two U joints will connect the motor and the thrust bearing effectively splitting the distance of the long shaft in half. Thus, the drive part of the drive-line will be aligned at the main bulkhead and the cutlass bearing, but the other half from the motor to the bearing will be free to move as do shafts in a rear-drive vehicle. I hope to get pictures of the installation up when I reach that point.

Without a thrust bearing, the whole drive line would want to buckle up at the U joint. Note the Aqua-Drive unit uses constant velocity joints instead of U joints. There probably is an extensive thread on this type of drive-line within the cruisers'forum or elsewhere on the net. I haven't looked yet.

Jmolan · 07-05-2011, 12:45

Hello! I have not had time to barley check my email lately. Shipyard for a 125' is beyond 24 hours a day.
Mark I did stumble on Spar Talk and hope you have had your questions answered. We cruised for 6 week and never noticed a big difference form morning till night. Maybe I have the shrouds pre-tensioned enough to eliminate it? I will try to check the runner next time I am there. Not nearly so much tension on that.

Issues with synthetic rigging? - SparTalk

I also see a guy posted photos of his gaffer in dux. Very nice!

Is great to see many new faces and boats! I hope to get a break soon and be able to catch up on the reading and correspondence!

Roy M · 07-05-2011, 18:38

Phantom, Go with the single shaft, hard mounted to the engine. Anything in between simply increases the chance for "play" when vibration is an issue. As for the engine beds, DO NOT MOUNT THEM ON ALUMINUM BEAMS OR ANGLE STOCK. What will happen is that the heavy engine will begin to heave and lurch at certain RPMs and loads, increasing the vibration enormously. Go with solid lumber beams, glassed and painted, then capped with angle (if you think it helps). Or, go with strong foam beams with angle well secured into the beam. The engine mounts need to have a substrate that can handle the huge torqueing that goes on when spinning a shaft in tough going. If anything, go overboard in the construction of this one element.

A couple of other items to consider: oil filters often are mounted low down and horizontal, causing awful messes when changing filters. I mounted a Fram hot rod filter assembly to a vertical bulkhead, and used custom high pressure hoses to connect to the engine. Better filtration and much easier replacement. Put a drain hose in the bottom of the AquaLift muffler assembly to drain it when having to get a recalcitrant engine started. It keeps water from backing up into the exhaust manifold. If your oil dipstick is hard to get to (mine is very close to the centerboard trunk, go to the auto parts store and get a replacement (mine was from a Chevy) that emerges at the top of the engine. I simply inserted a length of copper tube into the dipstick hole and it helps guide the dipstick into the engine. Then mark the oil level with a file or cut a notch for the right level. Install a Racor vacuum gauge near the instrument panel in the cockpit, run some automotive vacuum hose to it, teed off of the intake of the hose going to the fuel pump. It will tell you if your filter is about to plug up before you enter a rough inlet after a bouncy voyage mixes up the sludge at the bottom of the fuel tank. Then install a parallel fuel filter assembly with y-valves to change over to clean filter in a heart beat.

That's it for today. Project overload, mission creep, whatever one calls it, I have a tendency to mess around with something that already works. Right now I'm just trying to get the boat ready for the boatyard to install the centerboard.

Laidback · 07-05-2011, 18:50

Quote:

Originally Posted by PhantomBoatwork

I also have two flange mounted bearings for the bulkheads. What I need to know is whether a PSS shaft seal at the stern tube will give enough support at the inboard end, or do I need another bearing.

I was thinking of aluminum angle bolted to maybe 4x6 which could be epoxied to the bulkheads.

Add another Pillar block near the PSS.

Your plan to use an Aluminium Angle epoxied onto/into the engine bearers better than just studs epoxied in. Question :- how will you fix the engine mounts to the angle ?? Something like this ?

Roy M · 07-05-2011, 19:23

Sorry, one more thing about installing the shaft. The critical thing is the placement of the shaft strut/cutlass bearing. Once it's in, it can't get adjusted. So, cut the slot in the hull where the shaft will pass through the shaft log. Cut holes through the intermediate frames where the pillar block bearings will go, and a hole where the engine flange will be. Use a tight piece of string to approximate the centers. Then thread the shaft into the cutlass bearing/shaft strut, UNMOUNTED AT THIS MOMENT, continue passing it into the boat, through the shaft log, on through the pillar block bearings, to the place where the engine will be. Temporarily drill and bolt the shaft log, cutlass bearing and intermediate bearings in place LOOSELY. When everything is in place, begin to gently tighten the mounting bolts so that they move into their final positions. You check this by spinning the shaft with your hand, it should spin with little resistance. Now, temporarily install the shaft coupling to the shaft. Then, install the engine, with its mounts temporarily installed at the midway position, onto the engine bed. Note where the engine flange lies in relation to the shaft coupling. ADJUST THE ENGINE TO THE SHAFT COUPLING, wiggling the engine around on the engine bed logs until they approximate the mating of the two flanges. When it's close, you are ready to make things permanent.

Mark where the engine mount bolts (or lag screws) will be positioned, then remove the engine. Remove the shaft coupling. Make sure the intermediate bearing(s) are flat against the bulkheads the shaft passes through, using a rubber mallet to pound them flat. Tighten the bearings again and make a mark wher they sit on the bulkhead. Later, if you have to enlarge any of the boltholes, it won't be a problem to set these bearings in place. Now, the fun parts: the shaft log and shaft strut, two parts that get solidly and securely mounted, PERMANENTLY. Use epoxy putty to fill the gaps between the hull and the bottom of these two bronze units. You can stuff in just enough to get the pieces to register. The remove the shaft, fill in the gaps to create a "wedge" that accomodates any missing support between the bronze and the hull. Slip the shaft back into the strut, cutlass bearings and intermediate bearings, drill the mounting holes out again, if they got filled with putty. Tighten everything up securely and check the shaft friction when you turn it by hand. Drill the holes for the engine mounting bolts or lag screws. Install the engine and mounts, and make a rough alignment with the shaft coupling. Remove the shaft coupling, intermediate bearings, and do any final epoxy sealing of the holes and slots, Redrill the holes if necessary. Have all your bolts, washers, and nuts ready, goop the bronze shaft log base (3M 5200), the shaft log base, insert the shaft into the slot and the intermediate bearings. With the assistance of a couple folks holding the various parts in place, install the fasterner bolts, ensuring that the shafts of the bolts are gooped (you don't want to goop the threads), then begin tightening stuff until goop squeezes out. Spin the shaft to ensure everything moves freely and correct before the goop hardens. Then do a next to final alignment of the engine to the shaft. After you launch the boat, you will do one more, final, alignment as the boat settles into its happy place.

Pat yourself on the back, because if everything moves freely at this point, the final installation will be a breeze.

Mark Johnson · 08-05-2011, 08:17

Quote:

Originally Posted by PhantomBoatwork

Ah, excellent forum and excellent post! Can I pick a few brains? This is for my CC 44 center cockpit tri by John Marples. I have an M50 Universal diesel - four cylinder, a Martec folding prop and allowances for an 1 1/8 shaft between the two. It isn't installed yet, as the motor is sitting in my garage and the prop is in my attic. I "bore sighted" the shaft tube with a laser and drilled the shaft hole through the bulkheads to the engine compartment. I also have two flange mounted bearings for the bulkheads. What I need to know is whether a PSS shaft seal at the stern tube will give enough support at the inboard end, or do I need another bearing. The stern tube will have a cutless bearing about 40 inches away. Also, does anyone have insights for the engine supports? I think John suggestged 2x6 with threaded rods bonded in, butr I was thinking of aluminum angle bolted to maybe 4x6 which could be epoxied to the bulkheads. What have you lother guys done. My engine and tranny is about 545 lbs. I reversed the centerboard trunk when I built it so the exhaust manifold is outboard, but I have never installed a marine diesel and I want to get it right. Any help out there?

The PSS shaft seal does not offer any support at all... M.

Mark Johnson · 08-05-2011, 08:31

Quote:

Originally Posted by Rann

The big issue with a coupling and shorter shaft is including a thrust bearing in the coupling. The Aqua-Drive system is such an arrangement. The thrust bearing must be mounted on a major part of the boat such as a main bulkhead. Thus the prop is driving the boat via that bulkhead instead of pushing the motor. I have just such an idea for my 34. I had a friend make me up a unit I plan to mount to the aft main bulkhead. It is a bearing unit with a U joint coupling common to U.. vehicles. The bearings are within a housing with oil seals and a zerk fitting for maintaining lubrication of the bearings. Two U joints will connect the motor and the thrust bearing effectively splitting the distance of the long shaft in half. Thus, the drive part of the drive-line will be aligned at the main bulkhead and the cutlass bearing, but the other half from the motor to the bearing will be free to move as do shafts in a rear-drive vehicle. I hope to get pictures of the installation up when I reach that point.

Without a thrust bearing, the whole drive line would want to buckle up at the U joint. Note the Aqua-Drive unit uses constant velocity joints instead of U joints. There probably is an extensive thread on this type of drive-line within the cruisers'forum or elsewhere on the net. I haven't looked yet.

All very good points Rann! Our AquaDrive CV joint REALLY simplified the installation. With our engine in the galley area, below the cabin sole, it has a much shorter shaft than you guys are having to deal with, but for you, as an intermediate bearing in a very long shaft, it has possibilities. It also makes the PSS shaft seal work better, as the shaft only spins, rather than spins and SHAKES with the engine. The "thrust bearing" feature lakes the load off of the engine feet, making them last longer, and if you snag a crab pot, it could save your transmission bearings! Our AquaDrive installation 15 years old, in perfect shape, and some of the best money spent on the boat! I have not had to realign the engine since we launched in '96! I credit John Marples for the ideas on alternate engine location, AND the CV joint... Thanks John.

Mark

Mark Johnson · 08-05-2011, 09:29

Quote:

Originally Posted by Jmolan

Hello! I have not had time to barley check my email lately. Shipyard for a 125' is beyond 24 hours a day.
Mark I did stumble on Spar Talk and hope you have had your questions answered. We cruised for 6 week and never noticed a big difference form morning till night. Maybe I have the shrouds pre-tensioned enough to eliminate it? I will try to check the runner next time I am there. Not nearly so much tension on that.

Issues with synthetic rigging? - SparTalk

I also see a guy posted photos of his gaffer in dux. Very nice!

Is great to see many new faces and boats! I hope to get a break soon and be able to catch up on the reading and correspondence!

Hi Jack,
Welcome back. Yes I did get a number of responses about my questions. I don't know what the temperature differences from morning to night are in the Sea Of Cortez, but here, they can run as much as 40 degrees F! I also don't know how hard you push your boat in high "20 something" winds? Like... if you tension your rig in 85 degree temps, then go out and push it hard in 45 degree temps, I think even your standard rig might have problems, but I could be wrong?

With our "4' taller, skinny rig", (same hight as the 37'er) these changes in tension would make it hard to keep the mast in column. This is only when sailing in the high 20s. In the 30s and above, I have rigged up the runners & raised the staysail, then it is REALLY stout! I could just "back off", but since I need to change my wire anyway, I want to solve this!

I can see that a lot of folks are having great success with replacing their entire rig with Dux, and with my adjustable runners, (even an adjustable staysail stay), it seems like a good option. For my rig however, I think I will switch from standard 316 SS wire, to Dyform = "compact strand" 316 wire. This will stay in tune year round, and keep the mast straight.

I would suspect that a LOT of rigs are less tension sensitive, and be better candidates for Dux, either short stout rigs, stout double triangular trimaran rigs, or even huge rotating extrusions, (or wing masts), with SS diamond stays to keep it in column, and a STRONG single triangular Dux rig, like on big cats. These rigs can have a larger temperature differential with no ill effects, and at rest, need almost no preload...

I have been looking for more and more places to use synthetics, to replace SS shackles and such, and even read of it being a way to connect anchor chain end for end, in a way that WILL go over a windlass capstan.

A friend recently gave me a gift of a "softie" piston hank replacement that he had made. I was pleasantly surprised! It seems incredibly simple, strong, and reliable. He said that when in practice, and making dozens of them, it gets down to about 15 minutes each. At this rate, one could replace them every year, if chafe was a concern. They're pretty slick!

Regards, Mark

Ret-Tri · 08-05-2011, 17:31

Searunner 40 for sale at Sailing Texas Sailboat Classified Searunner 40, 1979, Offshore Cruising Trimaran, Seattle, Washington, sailboat for sale from Sailing Texas

It's the Seafire mentioned by md7a.

CharleyAnna · 08-05-2011, 18:22

Hello everybody
I need advice too! The amas of my boat (31') are new, never been in the water. (Too remind you guys, we bought the boat from a widow--husband/builder had died and widow knows nothing about boat). From what my inexperienced eye can tell, he wasn't really finished with the 'gelcoat'. I'm saying it's gelcoat only because people have told me it is. I was fine with that until hearing Mark's reply to the person in St. Thomas about bottom paint. Now it all seems so complicated!!! So the term gelcoat means it's polyurethane and not epoxy, right? Do the two look different enough that one can tell?
The finish has 'orange peel' looking areas, as well as other various runs and uneven spots. Today I sanded one ama with 150 grit sandpaper. Have been planning on doing some light filling of these areas, then applying another layer of gelcoat. However today I was on a boat builder forum, and I got the impression it may be better to paint at this point, with a two part type paint. I think they called it gel-something. Does this sound right? Or should I spray on another layer of gelcoat? (There are a few areas of 'dark' showing through and I can slightly see some fiberglass cloth near the bottoms of the ama in some places). Pictured below includes a close up of the worst area with dark showing (this area was really rough), and the fiberglass showing through. Thanks to you guys in advance.