Making Ex-Racer My Cruiser . . . Am I Mad ?

[MidLandOne]

Originally Posted by roverhi

Manganese Bronze may be a brass, but it doesn't suffer the zinc depletion that most brass does. So consider it a bronze which is probably why it's called bronze.

It does suffer zinc depletion if it is cast so that the beta phase is predominant - in normal circumstances it is predominent so manganese bronze should not be relied on unless there is assurance of the alloy eg by buying a reputable manufacturer's seacock. Lots of people have found that out to their distress. That is also why people who have poorly built manganese bronze propellers (being the predominent alloy used for sailboat props) find them turning pink and why those same people need to cathodically protect them on ss shafts even though the two materials should be galvanically neutral together if the alloy is correct.

Regarding the name insistance as to it being "bronze", just as you can call a dog a cat but in the end it is still a dog you can call a brass "bronze" but in the end it is just a brass. The "bronze" name, in fact, misleads many into being unaware of the particular care that must take in specifying or purchasing immersed components made from manganese bronze in order to assure its corrosion resistance.

Weyalan - I have spent many happy days sea trialling or just being given rides on new cats in and out from the Derwent. It is indeed very nice area.

[Weyalan]

Originally Posted by MidLandOne

Weyalan - I have spent many happy days sea trialling or just being given rides on new cats in and out from the Derwent. It is indeed very nice area.

Are you referring to the Incat vessels? Or the NWBS variety? I have done a fair amount of work on both. It is, as you say, a very nice area. Just don't tell anyone!

[MidLandOne]

NWBS. And happy to mention that clients were very pleased with the workmanship - they had had their more recent previous boats built in USA and those looked very rough by comparison to the Oz ones.

I promise not to tell anyone how pretty it is around Margate/NWB especially on a still misty winters morning - whoops, I need a hand over mouth icon to keep me quiet .

I assume that you were in a position to get some good advice for those unmentionable things recently referred to in the thread .

John

[Weyalan]

My father-in-law is a boilermaker welder, who built a steel Adams 40', and lives aboard. He told me that, as a rule, it is a good idea to stick with the same metals throughout the plumbing (thru-hull, elbow, ball valve, hose tail) and that in his opinion, problems as a result of dissimilar metals were more of a concern than the suitability (or otherwise) of stainless steel. A couple of commercial captains I know told me that the have and would continue to chose to go with stainless thru' hulls. The naval architect (who consults with McConaghy) also had no objections to my use of the stainless. Obviously, time will tell, but let me say that I am not unhappy with my choice.

I'm gonna take a punt and guess that you are an Austal guy, not a NWBS guy? I haven't done any work on the Austal boats built down here, but have a lot of input into the Henderson built ones. If you happen to be down that way next weekend, there is a fair chance you will see Insatiable slide by NW Bay, competing in a low key race to Kettering, with associated overnighting in either Rosebanks, Sykes, Quarantines or thereabouts, with a roast dinner and a few Cascade draghts, no doubt.

[Wotname]

Can you guys please stop talking about the Hobart sailing environs .
First it is making me very envious especially as I am doing my best to relocate there - but gotta finish refit, sea trials (especially sea trials of me) and then a coupla thousand miles at 40 S.
Second it might make the place too popular - (but "I'm allright Jack")

Maybe just some more reports of knockdowns or similar entering the Marina .

[MidLandOne]

No, I'm over in NZ Weyalan so not with Austal - the vessels I managed were for a North American region client.

Some years back some American friends sailed from NZ westwards towards home intending to spend a year cruising Oz on the way. I suggested it might take longer than that (especially as the wife was once a zoologist) - first stop was Tasmania and they spent a year there before even getting elsewhere .

[Weyalan]

Just finished the teak frames to trim the new hatches. We made them ourselves, from scratch... each one is made from 8 parts (4 straights, 4 radiused corners) joined with double dowels they were very time consuming, but look absolutely terrific. We will go through a similar process for the inside window frames too, I think.

Also, last night, laid the carbon fibre for our new bench tops in the head area. Never having laid carbon fibre before, and never having laid fibre for for cosmetic effect, it was a pretty stressful process.... the benches have rolled front edges and one has a radius of about 150mm at the corner, so we were worried about getting the carbon cloth around the curves without distorting the weave, It has actually turned out really well.

Yes, I know... photos required... I will soon, I promise.

[Pblais]

Yes, I know... photos required... I will soon, I promise.

I just hate it when have to beg. Sounds encouraging. Just goes to prove you just can't always know what you can't do.

[Weyalan]

Originally Posted by Pblais

Just goes to prove you just can't always know what you can't do.

I have learned that although I am not particularly skillful, there is almost nothing that we attempt that we cannot either do, or mess up and then fix, or mess up and do again until we get it right. If you don't have a go, you never know.

[MidLandOne]

Originally Posted by Weyalan

Also, last night, laid the carbon fibre for our new bench tops in the head area. Never having laid carbon fibre before, and never having laid fibre for for cosmetic effect, it was a pretty stressful process.... the benches have rolled front edges and one has a radius of about 150mm at the corner, so we were worried about getting the carbon cloth around the curves without distorting the weave, It has actually turned out really well.

I would be very interested in some more comment (and photos ) as to the background to your use of carbon fibre for the bench tops and how they will be finished.

As I have not reread all the many pages of the thread again if it has already been described just tell me so and I will hunt it out .

[Weyalan]

Originally Posted by MidLandOne

I would be very interested in some more comment (and photos ) as to the background to your use of carbon fibre for the bench tops and how they will be finished.

Photos to come, but here is the skinny...

The bench tops are for a vanity and a cupboard in our refitted head area.
We made the bench tops from 10mm marine ply, cut to the appropriate shape. They had to be made in conjunction with the main structure of the cuboards, so they ended up with lots of drilled holes from the building process, which we have subsequently filled and sanded flat

On the leading edges we added a double thinkness of ply (glue & screw with epoxy/glue fibres, with screws subsequently removed and holes filled) to make it look more solid, and then rounded the duble thickness with a router to give a rolled edge. (with hindsight, it might have looked even better with a triple thickness to give a bigger round, or perhaps 2 x 12mm ply instead of 2 x 10mm, but it looks good anyway). The glue/screw process did put a slight bow in the benchtop, so we probably should have clamped the whole thing to a bench at the time, rather than just clamping the 2 pieces of ply, but we fixed it laster (read on).


We laid biaxial fibreglass on the underside of the benchtops, for added stiffness and to straighten the aforementioned slight bow. Because the underside of the benchtops are inside cupboards and are therefore pretty much invisible, they will probably just get a coat of high build primer and a coat of top coat. If it were somewhere visible, we would probably fair it with epoxy/microballoons, but it ain't so we didn't.

We coated up the surface with a coat of expoxy resin. Normally we would coat with Everdure (or the Wattyl equivalent - just as good, 1/2 the price), but Everdure soaks in so much but we wanted a good smooth surface so that the carbon cloth wouldn't get caught as we laid it. With hindsight, it might not have been too necessary, although you would want some sort of pre-coat to stop your epoxy getting sucked into the wood, rather than the cloth.

We cut the carbon out to shape, with a small amount extra right around. We actually laid masking tape onto the cloth and cut it through the middle of the masking tape, but this may have been overkill and we had to cut the masking tape of later anyway wherever we were rolling around an edge. You need very sharp scissors

We wetted-out the surfaces for teh carbon with a good coat of resin (don't put any extra catalyst in at this stage... chances are you are going to be messing around a fair bit, so you don't want your resin to go off in a hurry)

We floated the carbon cloth down by holding the corners. With hindsight, this was probably sup optimal... even the weight of the cloth will make it sag and distort the weave. When we next to this we propose to roll the cloth onto a pice of PVC tube and then rollthe tube over the job to get the cloth to fall onto the surface with the weft and warp perfectly straight. In fact, you have to look very very carefully at our job to see that the warp and weft are a little bit off-straight, and Lisa & I will probably be the only people that notice it. Note, also, if when you get the cloth down, you are not happy with it, you can easily pick it up again and re-lay it, although the extra resin it will have absorbed does make it want to sag more. We ended up lifting and repositioning the cloth on the biggest bench top about 3 times before we were happy (hence the idea to use a PVC tube next time).

Once you have the cloth down and you are happy with it, wet it out thoroughly - do not skimp on the resion... remember this is for aesthetics, not for weight / strength, so the resin/cloth ratio is irrelevant. Don't worry if you can see plywood through the weave, as you wet out the cloth, it will swell and close the gaps. We used 1.5" disposable brushes and a steel roller, which seemed to work out fine.

The tricky bit is rolling the cloth around the corners; do it gently or you will disort the weave - use your fingers if necessary. Once you have got the cloth rolled around to your satisfaction, carefully trim off enough as much excess as you can, because excess cloth will tend to want to make the cloth sag or fall off the underneath of your rolled area. Once you have trimmed it, you just have to keep an eye on it and keep pusing it back up if it starts to sag until the resin goes off sufficiently to hold it in place - that was, for us, about every 10-15 minutes, for about an hour, after which we could leave it alone.

That is about all I can tell you for now. We are still deciding whether to add an additional coat of epoxy, or go straight to 2-pack varnish. We will have to let the resin cure for a couple of days before trimming the excess cloth at the edges back hard (probably with a grinder, because I reckon the stanley knife will struggle).

Thats all I can tell you at this stage, but I can assure that the results end up looking spectacular. A friend used it for benchtops on the refit of his 50 footer... just awesome. Photos soon...

[Pblais]

If you don't have a go, you never know.

As I liike to say you have to be present to win and it is mostly about showing up.

[Joli]

Looking forward to the photos Weyalan.

[procrew4u]

Weyalan sounds like a tough boat and what would they know, restored one-tonners make the toughest cruisers and you will be able to build the interior the way you want it, heck I'll help you sail it and show all these people it doesn't cost much, anyone want to challenge it, find one and be surprised.

[Weyalan]

Just an update on the carbon fibre benchtops:

we have found that it is taking quite a few coats of varnish with vigorous hand sanding (320 grit) in between to flatten out the natural highs and lows created by the weave of the carbon. We have already put on 2 thick coats (brushed on) and it is looking like 2-3 more coats (small mohair roller) before we will get to a perfectly even finish. They do, however, look really good (or so I think).