Fibreglass mat or fibreglass cloth?

I'm getting a distinct feeling of desperation to take the boat to sea.Regardless.I'll leave you to it.

 

Reference is good sense.

When you lay a larger piece of glass over a small; the likelihood of entraining air at the step is high; nearly certain. Sand through of the top layer is dependent upon glass thickness, but laying 3 tabs of say 6 oz glass would result in sanding through easily.

There is no shingle effect in glass laminate either, so nothing magical happens in layering. It has been widely discussed on the forum.

There are times when the work may be best smaller first in patching, for example, where it is easier to determine the shape of the smaller patches first. In those cases, best work would require augmenting the smaller piece edges with bonding putty prior to the next layer getting fin rolled (again to reduce air).

But it isn’t an American standard, just a best practice.

If you’ve ever laid up glass upside down on a table wetout where you carry to the location, doing the smallest pieces first also results in air entrainment and this can be really a difficult situation to remedy with bonding putties due to time constraints.

Also; if you are laminating say hull chines with something like (as a courtesy I provide in metric), staggered 150mm tapes followed by a 100 or 200/150/100, the same is true; a 40 foot hull chine is a real pain to putty going 100/150/200, and so 200/150/100 results in no need for putties and less air pockets on the steps.

Also, if you ever use pre-release methods, shortest first would result in poorer bonding as it would be very hard to sand the steps well.

 

Wow,a lot of opinion but nothing of note cited.In the early 1980's I followed a designer's specification for bonding reinforcements into an Admiral's Cupper.It was the first time I encountered detailed specifications for laminate material and fibre orientation,with recommendations for daily maximum layup..There have been numerous others since and guess what?

 

When discussing large to small or small to large layering with engineers it typically comes down to the exact project, sometimes it makes no difference and others time you want to do it a specific way.

I built high pressure composite vessels for a couple of decades. When joining sections together you always started with the largest/widest glass first, then smaller pieces on top of that. You want the fibers to be as straight as possible with no bends as you would get by laying a larger piece of glass over a smaller one.

These sections weren't tapered so you didn't have a valley or low area to fill, it was all built up on top of the existing section.

In less demanding situations it isn't as critical, so you may choose to do it the easiest, most convenient, or quickest way.

 

It wasn’t opinion. I backed it up with cogent reasons.

 

As ever,ondarvr gives a good real world explanation of the case he describes.My own involvement with composite pressure vessels is only peripheral in that I have seen a few examples that were bought in to serve as accumulators on high pressure hydraulic systems-circa 2500psi.They were CNC filament wound and they worked.The extensive waffle from fallguy doesn't provide links to actual bonding specifications from designers or composite engineers or documented test results.I have stated that bonding specifications from a cluster of designers and composite engineers always started small and got larger,usually specifying the amount of overlap and fibre orientation of each ply.Those people have had solid careers in the worlds of boats and composites.

We are a long way from dealing with a beat up Nicholson and as I posted earlier,we have a resolutely determined owner who wanted confirmation of his intended action being wise.I don't think it is and will say no more about it.

 

I appreciate your opinion, and I do take it into consideration. But there are also opposites views, and I also spoke with the surveyor who although thinks structural repair is necessary (the boat most likely came into the dock during a storm with its mooring lines improperly adjusted, and inside damage/cracks part probably due to anchor/chain) but is best to do it later properly rather than a quick fix now that would not do anything. The key point here is that there's no visible progress of the damage over the years, and I'm not planning to have an extensive sailing season or sailing in a heavy whether.

Just to explore this idea of putting a wood chunk (orange rectangle) and a metal plate (red) below the plate as a temporary solution. Let's assume this is a structural damage with no visible progress in the damage and no flexes when stepped on it. But then let's also assume that there are non-visible cracks on both sides (purple lines). In this case, I'm questioning if this solution would do anything? As an alternative, to be sure there's no real risk of demasting, what do you think of one big chunk of wood (blue rectangle) bolted to the bottom? Optionally, 2 pieces of wood on both side (green) fixed on the sides to form an inverted "Y" structure.

 

The idea of wood under was offered only to prevent the anchor from breaking out the section.

The idea was offered based on the premise the anchor is causing the section to flex in waves.

Given the fact there is another stress with the rig to the area; it is really hard to suggest that a piece of wood bolted below would help much. But if there is flex happening, then the wood bracket may offer some help. If the flex is from the rig, I probably would not run the boat.

 

Thanks, understand.

There's no flex in this area, all is stable there (as evidenced also on the photographs 2021-2026). I'll remove the anchor during the sail just in case.

I thought this extended wood or Y structure would give another layer of security, but if it doesn't do anything in this case, then I'll disregard this.