Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 07-02-2016, 01:35   #106
Certifiable Refitter/Senior Wannbe
 
Wotname's Avatar

Cruisers Forum Supporter

Join Date: Jan 2008
Location: South of 43 S, Australia
Boat: Van DeStat Super Dogger 31'
Posts: 7,333
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by clockwork orange View Post
……..
The boat in question is simply a strip planked mahogany boat, edge glued with either epoxy which could be one of many brands that have been available in NZ for decades before West came along, or has been suggested, just as likely, resorcinol and almost certainly sheathed with glass in epoxy, again, with whatever brand the builder preffered. What has not been mentioned is the rest of the construction above the sheerline which is most likely all BS1088 marine ply, species unknown and not important as long as its BS1088, this is what most marine plywood manufacturers in the world except the US uses to make a consistent high quality panel (consequently we make the worst marine ply in the world here) Everything above the sheer will also be glassed with epoxy and painted with 2 part polyurethane. This type of construction is as watertight and low maintainance as any fiberglass boat……….
While BS1088 is a very good standard for marine ply, an even better one is AS/NZS 2272-2006. Of course, this mainly applies to Aussie readers but in case anyone else is interested, it exceeds BS1088 in several areas.

AFAIK, Austral Plywoods are the only manufacturer using AS/NZS 2272 -2006 and they exclusively use Hoop Pine for all veneers.

It is a beautiful ply to work with
See more here Austral Marine Plywood
& Australian Standard AS/NZS 2272:2006 Marine Plywood
__________________

__________________
All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find it was vanity: but the dreamers of the day are dangereous men, for they may act their dreams with open eyes, to make it possible. T.E. Lawrence
Wotname is offline   Reply With Quote
Old 07-02-2016, 07:55   #107
Registered User

Join Date: Dec 2007
Location: Duluth,Minnesota
Boat: Lindenberg 26 & Aloha 8.2
Posts: 984
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by Wotname View Post
While BS1088 is a very good standard for marine ply, an even better one is AS/NZS 2272-2006. Of course, this mainly applies to Aussie readers but in case anyone else is interested, it exceeds BS1088 in several areas.

AFAIK, Austral Plywoods are the only manufacturer using AS/NZS 2272 -2006 and they exclusively use Hoop Pine for all veneers.

It is a beautiful ply to work with
See more here Austral Marine Plywood
& Australian Standard AS/NZS 2272:2006 Marine Plywood
Yes I have heard about this standard and will read up on it but unfortunately have never had the opportunity to lay hands on it. While I believe it may be better than BS1088 it really does not need to be, in over 40 years as a professional boatbuilder I have used hundreds of sheets of BS 1088 marine plywood manufactured in Holland, France, Israel, Australia, New Zealand, Phillipines and even China and consistency has been the common theme. Unfortunatly living in the US where really the only good species for making plywood is Douglas Fir and it is an excellent species, the mills don't build to BS1088, consequently in 35 years here I have yet to see anything I would put in a boat. What they call marine plywood can have repairs in the face veneers, voids, overlaps, not enough veneers and on and on,truly horrible stuff when compared to the consistency of BS1088,fortunately we can buy imported BS1088.
Is anyone in Aus making Kiri marine plywood yet? now that would be the holy grail. As I write this I have sitting next to me a sample piece of Chinese made 18mm plywood(not marine) with thin birch faces on a 7 ply core of kiri, it is marvelously lightweight and beautiful, it is a 79 in2 sample and weighs just 11.7oz which translates into 43lbs for a 4x8 sheet compared to 60lbs for okoume. Unfortunatly it failed the boil test as expected.
__________________

__________________
clockwork orange is offline   Reply With Quote
Old 07-02-2016, 08:12   #108
Freelance Delivery Skipper..
 
boatman61's Avatar

Community Sponsor
Cruisers Forum Supporter

Join Date: Jan 2010
Location: PORTUGAL
Posts: 20,217
Images: 2
pirate Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by Wotname View Post
Hmm… 1970… presumably the instructors were what, say 40+ (al least 30+) so they learned their stuff in 50's and 60's and were (again presumably) current with the trends on the early 70's. If so, what they told you was pretty accurate given the polyester resins of that time.

Since then, we have moved on and very few people who know anything about wood and resin, would consider using a basic polyester resin and wood in the same sentence

So yes, they were right, but they are not right, right now

An NZ professionally boat (as like the OP is looking at), will have used epoxy resin and either be sheathed with either fibreglass or dynel and I would be willing to bet it is more likely to be dynes.

Any rot found will not be from the construction method, rather from lack of maintenance / care.
Wot ^^^e^^^ Sed..
__________________


Born To Be Wild
boatman61 is offline   Reply With Quote
Old 08-02-2016, 21:20   #109
Registered User

Join Date: Feb 2014
Location: Niagara Falls
Boat: Westsail 32
Posts: 346
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by Wotname View Post
Hmm… 1970… presumably the instructors were what, say 40+ (al least 30+) so they learned their stuff in 50's and 60's and were (again presumably) current with the trends on the early 70's. If so, what they told you was pretty accurate given the polyester resins of that time.

Since then, we have moved on and very few people who know anything about wood and resin, would consider using a basic polyester resin and wood in the same sentence

So yes, they were right, but they are not right, right now
We had epoxy resins then, and the instructors talked of them as required.
__________________
Seymore is offline   Reply With Quote
Old 08-02-2016, 22:03   #110
Registered User
 
Capt Phil's Avatar

Join Date: Jun 2010
Location: Stateline NV
Boat: Prior boats: Transpac 49; DeFever 54
Posts: 2,749
Re: Would you buy it? Fibreglass over Mahogany

When doing a total refurbishment/rebuild of a 1966 strip mahogany plank plank runabout for show and light lake use a few years ago, we used penetrating epoxy to stabilize and strengthen the hull and soaked the hull thoroughly before glossing. It added some weight, maybe 200 lbs but we fe let it was agood compromise for the added strength and integrity.
Capt Phil
__________________
Capt Phil is offline   Reply With Quote
Old 09-02-2016, 10:03   #111
Registered User
 
Cadence's Avatar

Join Date: Dec 2008
Location: SC
Boat: None,build the one shown of glass, had many from 6' to 48'.
Posts: 6,063
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by Seymore View Post
Around 1970 I enrolled in a fiberglass course in Sheridan College in Toronto, near the airport. The course was a beauty. They had molds for canoes, prams, dinghies and all. We chose the boat we wanted, split up into groups, sprayed the gelcoat into the molds, laid up the mat and roving and turned out boats for ourselves.

That was one of the things the instructors told us: Never cover a wooden boat with fiberglass, it'll let water (vapour) seep in and won't let it out. The boat will rot relatively quickly.

For experience, I have seen lots of wooden boats with hulls covered with fiberglass, all of them seedy with the fiberglass letting go. I can't remember any solid wooden boats with competent fiberglass hull covering. But this is lightweight experience. I don't much go near wooden boats with fiberglass covering.

Wooden boats (on their own, without fiberglass) are OK by me, although I've had one and wouldn't have another. You can replace any piece of wood in a wooden boat, so it can last forever if you keep up with it.
In 1970 he was probably speaking of polyester resin? West or System Three on marine ply. seems to be reliable providing the ply is scarfed right.

I would agree covering a planked hull? I guess as a last resort it can have some usefulness. I had made friends with a live aboard couple that had glassed the hull of their 1917 50' Trumpy. She was still afloat.

I question the glass letting water in. I can see it not letting condensation out and causing rot JMHO
__________________
Cadence is offline   Reply With Quote
Old 09-02-2016, 20:45   #112
Registered User

Join Date: Feb 2014
Location: Niagara Falls
Boat: Westsail 32
Posts: 346
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by Cadence View Post
In 1970 he was probably speaking of polyester resin? West or System Three on marine ply. seems to be reliable providing the ply is scarfed right.

I would agree covering a planked hull? I guess as a last resort it can have some usefulness. I had made friends with a live aboard couple that had glassed the hull of their 1917 50' Trumpy. She was still afloat.

I question the glass letting water in. I can see it not letting condensation out and causing rot JMHO
He used the words that I said, and didn't differentiate between polyester and epoxy as I remember. He didn't elaborate.

You're right, the inference was that water vapour type intrusion would occur, not that torrents of water would pass through.

For the OP, a moisture meter run around the inside when the boat is hauled should show up problems of this nature.
__________________
Seymore is offline   Reply With Quote
Old 10-02-2016, 01:19   #113
Marine Service Provider

Join Date: Sep 2008
Location: Victoria B.C.
Boat: CS27
Posts: 1,743
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by Seymore View Post
He used the words that I said, and didn't differentiate between polyester and epoxy as I remember. He didn't elaborate.

You're right, the inference was that water vapour type intrusion would occur, not that torrents of water would pass through.
Epoxy is just about as waterproof as a coating can get. That is why polyester boats are barrier coated with epoxy. Nobody barrier coats with polyester.

If he didn't elaborate he was most likely referring to the common coating of the time - polyester.
__________________
mitiempo is offline   Reply With Quote
Old 10-02-2016, 06:08   #114
Registered User

Join Date: Dec 2007
Location: Duluth,Minnesota
Boat: Lindenberg 26 & Aloha 8.2
Posts: 984
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by Capt Phil View Post
When doing a total refurbishment/rebuild of a 1966 strip mahogany plank plank runabout for show and light lake use a few years ago, we used penetrating epoxy to stabilize and strengthen the hull and soaked the hull thoroughly before glossing. It added some weight, maybe 200 lbs but we fe let it was agood compromise for the added strength and integrity.
Capt Phil
Wow, do you remember what brand that penetrating epoxy was? That's some impressive stuff, most people find that penetrating epoxy barely penetrates at all but for yours to consume about 20 gallons on a runabout it must be saturating the wood. I have always considered the so called penetrating epoxies which are highly loaded with solvents to be useful only as coating in non critical areas. I do like them for very select purposes and have used Epiglass evedure, tried the Smith stuff and currently have been using some made in Florida.
__________________
clockwork orange is offline   Reply With Quote
Old 10-02-2016, 08:32   #115
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by mitiempo View Post
Epoxy is just about as waterproof as a coating can get. That is why polyester boats are barrier coated with epoxy. Nobody barrier coats with polyester.

If he didn't elaborate he was most likely referring to the common coating of the time - polyester.



Vinylester is a superior water barrier to epoxy. Epoxy guys just spend way more on advertising.
__________________
O you who turn the wheel and look to windward,

Consider Phlebas, who was once handsome and tall as you.
minaret is offline   Reply With Quote
Old 10-02-2016, 18:00   #116
Registered User

Join Date: Dec 2007
Location: Duluth,Minnesota
Boat: Lindenberg 26 & Aloha 8.2
Posts: 984
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by minaret View Post
Vinylester is a superior water barrier to epoxy. Epoxy guys just spend way more on advertising.
This is the main reason why so many newbies think that epoxy is the only option, massive advertising. I doubt that I have ever seen an ad for polyester or vinylester in a retail boating magazine. Epoxy is the way to go if bonding wood is involved, otherwise VE is a great product. VE is what underground fuel storage tanks are made with.
__________________
clockwork orange is offline   Reply With Quote
Old 10-02-2016, 19:10   #117
Senior Cruiser
 
Jim Cate's Avatar

Cruisers Forum Supporter

Join Date: May 2008
Location: cruising SW Pacific
Boat: Jon Sayer 1-off 46 ft fract rig sloop strip plank in W Red Cedar
Posts: 11,465
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by minaret View Post
Vinylester is a superior water barrier to epoxy. Epoxy guys just spend way more on advertising.
That's pretty interesting, Minaret! If so, and I am not doubting your knowledge, is there a barrier coat product utilizing VE similar to the Interprotect epoxy that many (including you, IIRC) often recommend?

Jim
__________________
Jim and Ann s/v Insatiable II , lying Port Cygnet, Tasmania once again
Jim Cate is online now   Reply With Quote
Old 10-02-2016, 19:13   #118
Resin Head
 
minaret's Avatar

Cruisers Forum Supporter

Join Date: Aug 2007
Location: Seattle WA
Boat: Nauticat
Posts: 7,201
Images: 52
Re: Would you buy it? Fibreglass over Mahogany

Quote:
Originally Posted by Jim Cate View Post
That's pretty interesting, Minaret! If so, and I am not doubting your knowledge, is there a barrier coat product utilizing VE similar to the Interprotect epoxy that many (including you, IIRC) often recommend?

Jim


There is indeed. Duratec. I do, however, prefer 2000e. Which is a modified epoxy.



http://duratec1.com/duratec/?p=710
__________________

__________________
O you who turn the wheel and look to windward,

Consider Phlebas, who was once handsome and tall as you.
minaret is offline   Reply With Quote
Reply

Tags
glassed, mahogany

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Would you buy a boat that you knew has sunk in the past? Transporter2112 General Sailing Forum 59 14-01-2015 20:06
It's Never Over Until You Say It's Over maxingout General Sailing Forum 12 16-03-2009 17:32
Fibreglass over plywood experiment Brent Swain Construction, Maintenance & Refit 27 25-05-2007 19:15
Mahogany or Teak Cleats Pleiades Construction, Maintenance & Refit 10 15-01-2007 09:41



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:47.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.