Mast rake and mast bend on E30+: Seth, Guy, Martin....??

Hi,

I am beginning to talk with sail lofts about a new mainsail for our 1984 E30+ and one issue has come up repeatedly causing real puzzlement: mast rake and mast bend, and lack thereof on the E30+.

I have tuned our rig as recommended in the Ericson Rig Tuning Guide for the E30+ (a one page document available in the downloads for The e30s on this site), and the boat generally sails well--up to 7.8 knots in 15 - 17 knot wind. The helm feels balanced, the boat tracks nicely and only experiences significant weather helm in gusts above 25 knots when I am overpowered. :0

The mast is straight, does not fall off to leeward when sailing upwind in about 18 - 20 knots, lee shrouds are not slack, and as best I can determine, shrouds are tensioned to about 12% of breaking strength (as recommended I think by Brion Toss/Rigger's Apprentice); cap shrouds and lowers are a bit tighter than the intermediates. So all seems good--except that this boat being a fractional rig, it should have mast rake and pre-bend in the mast, and the sail lofts are very surprised when I tell them that it seems to have been designed to sail without rake and pre-bend (according to the Ericson tuning guide for this boat).

When I apply the manual back stay adjuster, the boat will flatten a bit if heeled a bit too much, but I can't detect noticeable mast bend even then. I have adjusted the headstay length on our Harken furler to it's maximum and tightened the turnbuckles on the backstay to their maximum to shorten the backstay a bit, so I don't have any more room there to create mast rake without replacing the headstay and backstay. So it seems that the rigger made the stays of a length to prevent rake/prebend.

So my question: Was the E30+ really designed to sail without mast rake and mast bend? If she sails well without, should I leave well enough alone, or am I missing something here? Any comments, explanations, advice from the experts or from other owners of the E30+ would be very welcome.

Thanks,
Frank

I have read those instructions before. My leeward shrouds seem pretty slack when sailing close to the wind in about 15 to 20 kts, but I have sighted up the back side of the mast when doing so and the mast appears to be straight and not falling off to leeward.

Maybe I need to adjust my tuning, but I am afraid to tighten too much as I have noticed that there are some hairline cracks in the gel coat around some of the chain plate fittings in the deck. I realize this may just be cosmetic, but still...

Also I have noticed that the large aluminum anchors (actually round rods) at the bottom ends of the chain plate adjusting rods seem to have pulled upward and cracked the surrounding fiberglass. (I'll have to take a picture next weekend so you can see what I am talking about.) Another reason I am being over cautious.

I didn't notice any mention of rake or pre-bend in those instructions. I actually loosened my back stay quite a bit because, to my eye, the top part of the mast seemed to have way too much bend in it compared to other fractional rigged boats I looked at. Of course, after saying that, I did see a fractional rig today on a boat in my marina that is raced and the bend at the top of the mast was quite pronounced; at least as much as what mine was before I loosened the back stay.

Shrouds and things

My own experience--30+ years with the same boat--is similar to yours in that the leeward shrouds on my E-27 were somewhat slack when hard on the wind. It never bothered me. It never bothered a professional rigger. As long as the top of the mast doesn't bend off to leeward, you've got it right.

I lost a chain plate on the upper--it cracked in two--on the port side in a race. Kept the stick up, but it was condemned at the boat yard I kept my boat at because of a wrinkle. Had everything else looked professionally at when the new mast was being made. All else was fine. But I would think that the aluminum rod question would require a second opinion.

Can't help with tuning a factional rig. Never had one.

If you are able to change your boats sailing characteristics when you adjust your backstay you are bending your mast (perhaps only slightly). I am assuming that when you say you don't see any bend you are looking at it at the dock (or mooring) not while sailing. (it will be easier to notice bend when the boat is still)

Thanks for all the replies so far. Aleks, I'm sure that tightening the backstay adjuster is having a slight effect in bending the mast, as I do notice that the boat flattens a bit when the wind picks up, as compared with when I slack the backstay (without any change in sail trim). But when I sight up the mast, either at the dock or under sail, the mast still looks pretty straight to me.

Part of the issue here is that in all my reading and talking with sailors, fractional rigs are designed and intended to sail and be tuned differently from mast head rigs. There seems to be consensus that fractional rigs should be tuned tighter, with more mast rake and mast bend. And shrouds should be snug enough to just begin to feel a tiny bit slack but not look slack on the lee side when sailing in brisk winds. If shrouds are allowed to go slack on the lee side, there is a risk of shock load when tacking, which is hard on the boat according to Brion Toss/Rigger's Apprentice.

On my E30+, the shrouds are still snug in the lee side when sailing upwind in 18 knots of wind, but I have measured fairly carefully and am fairly sure that I have about 12% of breaking strength in the upper/cap and the lower shroud, and slightly less in the intermediate one (experts say that seems to be about right, though one could easily go to 15% and some even say 20%, but I think that's too high for my comfort level). The mast remains straight and doesn't fall off to leeward as far as I can tell (60 year old eyes

I am not experiencing any lee helm, and only slight weather helm unless I am overpowered in a gust--then she rounds up real fast.:0 So from a sailing perspective, the boat feels good; but everyone is questioning the lack of mast rake and mast pre-bend and the E30+ tuning guide doesn't even reference either--so unusual for a fractional rig boat!!

Mark H., regarding your tie rods/chain plate, our previous owner had the base of the tie rod re-glassed on the starboard side (inside the cabin behind the cushions) as they were apparently coming loose there. Now they are enclosed in fibreglass and look very solid. Our boat also has some gelcoat cracks on both sides at the chainplates--the previous owner told me that he tended to overtighten everything on the boat, and he probably had the shrouds too tight at some point. As I understand it, if the tie rods are properly in place and adjusted properly, they should counterbalance the shroud tension and the deck should look flat, rather than be pulled up or down.

Thanks again everyone! Still waiting to hear from others....

Frank

The deck area around the chain plates, with the exception of the aforementioned cracks, looks fine; no apparent deflection.

The area I refer too regarding the tie rod anchors is, I think, actually the fiberglass liner inside the hull, not the hull itself. It's been a while since I looked at it but IIRC there are two holes cut in the liner for the anchor to pass through; centered in the anchor between the two holes is the threaded hole for the tie rod. It is the fiberglass at the top of the holes in the liner that is cracked; as if the the anchor has been pulled up further than the holes would allow.

I am pretty sure there was a fair amount of flex and settling/curing that went on after these boats were built. I have noticed it also at the top of the compression post where the deck seems to have settled almost half an inch. There is a large teak block attached to the side of the top of the compression post that kind of forms a pocket for the door to fold into. A vertical trim piece is attached to the saloon side of the compression post and I noticed that the two screws that went through the trim and into the teak block were actually bent downwards over time by the deflection of the deck. The screws that held the teak block from the head side of the compression post were also bent. The compression post itself does not seem to be deformed at all. All of this caused the door to bind at the top of the pocket under the teak block. Other flex issues (I believe) prevented the door from being fully unfolded into it's closed position; the width of the passageway somehow got narrower. As soon as I get the door trimmed to fit the space it will all be reinstalled.

Frank, One sure fire way to detrimine mast (or anything else) bend is to take a line to the top of the mast with a plumb bob at the bottom. Then look at the difference in space between the line and the mast. It should resemble an arc. There will be your bend. How far the bob will be away from the mast in a straight vertical line should indicate how far aft an otherwise straight mast is leaning.

Hope this helps,
Frank

Thanks for these additional replies. Mark H., I took a look at our E30+ boat tie rods inside the boat where you say yours cracked. I can see the liner that you are referring to. The previous owner of our boat had reinforced the tie rod anchor with fibreglass ( a shipyard did the work), so clearly there had been a problem there, but it did not crack the inside liner and the tie rods are now firmly in place. I think that's the key, to ensure that the tie rods cannot move.

Similarly, the previous owner had reinforced the compression post/deck area with an aluminum plate above the compression post to distribute the compression force of the mast across the deck. Many boats seem to need this at some point, and so if your deck is deflecting down under the mast step, you may want to consider this as well.

I hope that helps.

Frank.

Here are the pictures of the chain plate tie-rods and anchors. You can see in the pic of the cap shroud/intermediate shroud anchor how the top of the anchor has cracked the fiberglass liner; the anchor for the lower shroud does not have the problem.

In the approx. two years since I first looked at this it does not appear to have changed any. I did not get to the port side tie-rods but will try next weekend.

Mark,

I've looked at these pics a few times, and am still at a loss to figure out how the liner could crack there. The best I can come up with is that someone tensioned the shrouds too much, forcing the tie rod anchor up against the liner and cracking it. For this to happen, I would also be looking for some cracks in the actual fibreglass where the tie rod anchor is glassed to the hull--do you see any sign of movement there?

In my opinion the cracks in the inside liner are of no consequence, as long as the tie rod anchors are solid and the tie rods are effectively counteracting the pull from the shrouds.

On our E30+ the previou owner had re-glassed the anchors into the hull as there had been some delamination there. It now looks absolutely solid. I do have a couple of minor gelcoat cracks on the deck at the shrouds where a previous owner over-tensioned the shrouds. Some day I will repair them, but at this point I think they are only cosmetic (surveyor agreed).

Frank

Well, my theory, after becoming very familiar with this boat and seeing how much of the fitment of various things is very "hand made" without the use of templates or jigs (e.g. the cutouts for the fixed portlights) is that the holes in the liner were cut a little off center to the anchor piece or the liner was slightly out of position; the shrouds were tightened, the hull flexed and there was no space for the anchor piece to move up a little.

I don't see any cracks in the fiberglass around the ends of the anchor pieces. I am going to look at the port side tie-rods when I get to the boat later today.

In thinking about how those anchors had to be glassed into the hull it seems like there was plenty of room for misalignment. The anchor had to be inserted through the holes in the liner then glassed into the hull. I don't see how the liner could have been installed after the anchors were bedded.

You are getting mast bend!

Frank,

I do recall sailing with you, and I can assure you the mast will bend as you apply backstay tension-and the headstay sag will be reduced. Adding backstay has the efect of removing some of the shape crated by the luff curve in the mainsail as the mast bends, and depowering the jib by reducing sag in the headstay-this is why the boat stands up and sails better as you add BS tension in breeze-you are depowering both sails. Even 2-3" of bend will have a big impact on mainsail shape, and you are certainly able to get at least this much bend. The question is not how much bend you are or are not getting, but are you getting enough to flatten the sail. If the sail does not have a lot of luff curve to begin with, you do not need very much bend to get it flat. If you feel you would like to be able to flatten the mainsail further, ease off on the lowers (which are aft lowers on your boat) and which restrict bend. If you have these tight, the lower portion of the mast will not bend and most of the BS load is transmitted to the headstay. From your description I think you may have things a bit too tight-certainly the lowers. The lee shrouds should not have any significant load when sailing in more than 10-12 knots of breeze. Not flapping around, but not tight. I would ease off 2-3 turns on the lowers, then go sailing. If as you sight up the mainsail track you now see the middle section of the rig sagging to leeward as a result of easing the lowers, then ease the uppers until it is back to straight. A slight fall-off to leeward at the very top of the rig is normal in 15+ knots of breeze (maybe 2" or so).

You cannot really induce prebend with a deck stepped mast unless you have fwd and aft lowers (like many other E boats), but you can adjust things to allow more bend (by easing the lowers), and you can certainly adjust rake by easing or tightening the headstay. It sounds like the rake is about right based on the balance you described, so just decide if you are able to get the main very flat with a good bit of backstay. If so, fine. If not, ease off on the lowers until you get enough bend to blade the main out with max bacstay, and play with the uppers as and if needed.

Call me with any questions (I think you still have my #).

Cheers