Moody 376 type of resin used for hull

Philippe Truchet

Temporary Member
#1
hello,
Expert evaluation just finished, and hygrometic measurement indicates a saturated level of humidity on a limited part of the hull. There are no blisters , but it seems that osmosis can be active without producing blisters, depending of gel coat porosity and quality. My question is to know what kind of resin was used for this 1990 boat (Orthophthalic or Isophthalic or other ...?) to evaluate the real impact of this humidity level before buying decision.

Thanks for your responses , ans sorry for my "french" english.

Philippe
 

Peter Wright

Peter Wright
Member
Boat name
WILD THYME
Berth
Suffolk Yacht Harbour
Boat type
Moody 425
Cruising area
North Sea, English Channel, Biscay
#2
Moodys of that era were laid up using isophthalic gel coat resin in a temperature and humidity controlled workshop. The gel coat thickness is generous compared with modern yacht construction. I don't know what resin was used for the rest of the lay up, but I imagine it would have been a standard orthophthalic resin.

The construction methods have resulted in the aging stock of yachts produced by Marine Projects being much more resistant than most of that era to osmosis, but no grp hull will remain immune to this problem forever if not cared for.

Peter
 

Philippe Truchet

Temporary Member
#3
Moodys of that era were laid up using isophthalic gel coat resin in a temperature and humidity controlled workshop. The gel coat thickness is generous compared with modern yacht construction. I don't know what resin was used for the rest of the lay up, but I imagine it would have been a standard orthophthalic resin.

The construction methods have resulted in the aging stock of yachts produced by Marine Projects being much more resistant than most of that era to osmosis, but no grp hull will remain immune to this problem forever if not cared for.

Peter
Thanks you for your detailed answer

Philippe
 

Peter Sims

Peter Sims
Member
Boat name
SIRI
Berth
Lefkas Marina
Boat type
Moody 44 (90s)
Cruising area
Ionian
#4
Hi Philippe
To go on from what Peter has said I think they used isophthalic resins for lay up as well by that time but if you want confirmation you could call Mike Lucas of Mike Lucas Yachting as he was Production Director at Marine Projects at that time
Regards
Peter
 

Philippe Truchet

Temporary Member
#5
Hi Peter

Nice suggestion, but I check in the member list and found Lucas names, but not Mike. Do you know how to contact him ?

Many thanks . Philippe
 

Peter Sims

Peter Sims
Member
Boat name
SIRI
Berth
Lefkas Marina
Boat type
Moody 44 (90s)
Cruising area
Ionian
#7
Hi Philippe
Good, but here are his contact details just in case. He's not a Moody owner. After Marine Projects he was the MD of Sadler and is now the recognised expert, and main broker, for the make. Tel: +44 7717 885435 e-mail mike@mikelucasyachting.co.uk
Regards
Peter
 

Philippe Truchet

Temporary Member
#8
Hi Philippe
Good, but here are his contact details just in case. He's not a Moody owner. After Marine Projects he was the MD of Sadler and is now the recognised expert, and main broker, for the make. Tel: +44 7717 885435 e-mail mike@mikelucasyachting.co.uk
Regards
Peter
Hi Peter
I've been in phone contact with Mike. His reponse can interest other members of the association : hulls build from 1988 used Isophthalic resin.
Regards
 

Alex Mansfield

Alex Mansfield
Member
Boat name
TWOFLOWER
Berth
Cagliari
Boat type
Moody 376
Cruising area
Mediterranean
#9
hulls build from 1988 used Isophthalic resin.
Hi Philippe,

thanks for posting Mike's response.

You don't by any chance know whether that meant the beginning of 1988? I'm asking since ours was built in 1988 (finished in May), hull number 142.

Our hull is coated in VC tar and some hard (epoxy?) coating on top. In some places this coating is now flaking off, leaving the hull in a rather rough state. At the moment we're contemplating about stripping the hull back to gelcoat and having it coated with a new protective epoxy coating (e.g. Hempel's High Protect) next month. However, the boat hasn't been out of the water for more than a few days in the past 6 years, hence we are wondering whether that would be a sensible move, or whether we should leave it alone. The moisture readings in the pre-purchase survey two years ago were ok.

While a smooth hull would be nice, the expense and the work of having her sandblasted and recoated with epoxy are substantial...
What do the MOA's experts think... would it be worth it?

IMG_6085.jpg


Thanks and best regards,
Angie
 

Peter Wright

Peter Wright
Member
Boat name
WILD THYME
Berth
Suffolk Yacht Harbour
Boat type
Moody 425
Cruising area
North Sea, English Channel, Biscay
#10
Hi Angie,

Overcoating epoxy tar with a hard epoxy seems a bit strange - I'm not surprised that it's starting to flake off.

The good news is that your moisture readings are OK, so you have no need to peel the gel coat.

It will be tough to get back to a decent finish without blasting the hull, which is not a cheap process. Whether it's worth doing depends on the state if your keel - if you have rust patches there then blasting and refinishing may also solve that problem. Getting rid of rust on cast iron is notoriously difficult because it gets into the pores, but I have found that pressure washing with fresh water, after grit blasting, helps a lot (it washes out the chlorides). Once the iron is dry, (another quick blast warms the surface and helps this) I think it's worth applying a coat of epoxy primer as soon as you reasonably can. I have used 3M's Scotchkote 152 LV, which was developed for steel on N. Sea oil rigs and claims to tolerate some rust and dampness in the substrate. I have also found that this works equally well as an epoxy primer on the gel coat, so the one primer can be used below the waterline.

While I'm a bit sceptical that you can get rid of rust on a cast iron keel, we used this approach for Wild Thyme 7 years ago and finished with Copper coat. She winters afloat, hauling for a few days each spring to wash and replace the anodes. The only rust that has appeared since then is on the foot of the keel - a consequence of ploughing the bottom of Dutch canals.

If you are considering Coppercoat, imho it's necessary to get the underlying finish good first. I don't like the idea of chunks of Coppercoat falling off because the layer below comes off.

So, in summary I think blasting/refinishing is the best approach to resolving the poor finish you have but, to get the best value from this, I would think about your long term approach to everything below the waterline.

Peter.
 

Alex Mansfield

Alex Mansfield
Member
Boat name
TWOFLOWER
Berth
Cagliari
Boat type
Moody 376
Cruising area
Mediterranean
#11
Hello Peter,

Thanks a lot for your detailed answer and recommendations.

We've been taking our time thinking about it as you suggested and I think we will most likely go a similar way to what you did on Wild Thyme. Our keel does indeed have quite a rust problem too, and treating that at the same time as the hull would be great.

How many coats of 3M's Scotchkote 152 LV did you apply, and how much did you need for your boat?

We're in touch with a yard about the blasting and Coppercoat vs epoxy plus conventional antifouling now and will based on their quote.

Thanks again and best wishes,
Angie
 
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