Mac 26D forestay chain plate

RussC · Apr 2, 2020

When I added a bow sprit to my Mac 25 I confronted the same issue. It sounds like your 26d has the same single bolt setup? the only issue is that it makes it difficult to seal the area where the plate exits the bow due to the constant slight movement, but there is, at least on my 25, a stainless reinforcement to keep the plate from cutting into the fiberglass. I considered adding a second bolt to the bottom of the plate, but ultimately left it as it was designed and it's never been an issue beyond needing new sealant every couple of years.

rgranger · Apr 2, 2020

@RussC
That is a cool mod. Is it a retractable sprit or is it fixed?

RussC · Apr 2, 2020

rgranger said:
@RussC
That is a cool mod. Is it a retractable sprit or is it fixed?

It's fixed, with an added bulkhead in the bow. works very well for the asem spinnaker.

rgranger · Apr 2, 2020

Professional!

justsomeguy · Apr 2, 2020

Ms Hope said:
The head liner inside blocks me from seeing the bottom of the chain plate.

Cut an access hole in that area as you see in Russ' photo.

williamtl · Apr 2, 2020

I too cut an access hole. Bolted the plate down (it was screwed originally) and of course used butyl tape to keep the water out. Note while working in that area I also found out the 3 deck cleats didn’t even have washers!

justsomeguy · Apr 2, 2020

williamtl said:
(it was screwed originally)

Do you mean the chainplate? That would be surprising.

RussC · Apr 2, 2020

justsomeguy said:
Do you mean the chainplate? That would be surprising.

I did a quick doubletake there also. pretty sure he meant the reinforcement plate on the deck, around the chainplate

rgranger · Apr 3, 2020

My Mac 22 used to have the same set up. I would unbolt the chainplate and clean up the surface under neat the tang (flange). If the rivet holes are blown, I'd lay up about six 1"x3" layers of epoxy wetted fiberglass cloth on a piece of plastic. Before you start, put tape around the edges of the plastic. Then from inside, I would lay that over the slit and tape it in place. In essence you would be making a strong backing plate out of fiberglass.

I've done this kind of repair several times. Thick plastic used as a drop cloth for painting works well but the best kind is the vis-a-vis slides your professors used to use for overhead projectors.

Once the epoxy sets, take a sawzaw or a coping saw and cut out the slit, put your chain plate back in place and then rivet the tang back in place. "Don't forget to put some butyl tape under the tang to keep water out. If you don't have a pocket riveter or can't borrow one, you could just as easily through bolt it with a 2" skinny SS bolt. That actually might be better because you could really squeeze the butly tape into place and make a water tight seal.

RussC · Apr 3, 2020

@Ms Hope photos are always your friend when trying to explain anything online

.

This is the single bolt referred to that secures the chain plate:

but if the flange plate on the deck

is missing it's rivets, then than that certainly needs to be addressed.

THECUSCUS · Apr 3, 2020

You can cut out a piece of the liner, to gain access to the chainplate. You could drill another hole and put another bolt in.
Or you can with alittle work, make a new stem head fitting, a do away with that chainplate.

williamtl · Apr 3, 2020

Ms Hope said:
The bow chain plate is bolted with a single screw head bolt that is on the starboard side of the hull. The cover plate used to be riveted to the bow but the rivets are gone.

This, this is what i meant.

RussC · Apr 3, 2020

When I took the earlier photos I shamed myself into re-sealing my reinforcement plate also. this required drilling out the rivets and then re-riveted the plate. so anyway..... wile I was there I took more photos for y'all

.

because of the geometry between the single mounting bolt, the point where the forestay attaches, and the installed forestay itself, there's quite a lot of force exerted to the rear side of the slot the chain plate sets in by the tensioned forestay. note the chainplate angle is almost vertical as shown by the yellow arrow shaft. this makes the reinforcement plate very important to keep from elongating the slot in the fiberglass.

When I installed my bow sprit I built a new chainplate to gain an extra 1/4" around it, but the OEM piece was actually almost identical to the one shown. as you can see, there isn't much opportunity to add another bolt to the bottom of the chainplate, and any leverage advantage really wouldn't help much regardless. which is why your reinforcement plate needs to be made secure again to support the load.

oh.. and BTW. the fiberglass under the reinforcement plate is VERY thick. if you plan to use rivets you'll want 3/16" rivets at least 3/4" long. 7/8"+ would be even better.

Rowlando · Apr 4, 2020

My solution was to use the anchor roller........drilled some holes in it to receive the forestay and supported it underneath with a large backing plate and a strap to the bow eye which needed work anyway as it was rotted out.

rgranger · Apr 4, 2020

I've been jealous of your anchor roller since you first posted that mod...

Giro · Apr 4, 2020

I have a question regarding the added bowsprit. From what I have read here, you have added the bowsprit to accommodate the spinnaker. I guess what you have done was to modified your MacGregor 25 sloop into a “cutter rig” sloop. Is my observation correct? If so, did you have to adjust the position of the mast in any way? The reason for my question is because I had a roller furler package set-up installed on my MacGregor 25 that came complete with a 135 percent Genoa when fully engaged. The problem is that I am left with a practically new jib sail and practically new 150 percent Genoa sail that I would like to be able to be able to use. I’m not sure that it would be safe and/or practical, but I guess just knowing that I might be able to use them if I wanted to would make me feel better. I’m thinking by adding a block at the masthead (or thereabouts) and adding the bowsprit would accomplish this. I’ve read that the placement of the mast, from an engineering standpoint, is critical. All bets are off if the mast would have to relocated. Any advise would be greatly appreciated.

Mac 26D forestay chain plate

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