How is your boat built?

A_8

A_8

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I am looking to change to a 45"+ flybridge and helping a friend find a 35"+ sports cruiser and we have gotten into a discussion how the different brands build their boats.

We are mostly thinking about some of the fundamentals that affects the hull integrity and ability to withstand stress and whatever else a boat typically gets exposed to, range is 34"-50" open, hardtop and flybridge boats and not more then 5 yrs old.

The build parameters we have tuned into so far are:

Cored bottoms or not?
Inner linings as part of the hull strength or not?
If above how/with what have the parts been glued together?
How have the lower and upper hull parts been attached?

Brands that we are mostly interested in are; Princess, Fairline, Jeanneau, Storebro Beneteau, Sealine and Bavaria.

I thought this might be of general interest to the forum and decided on this post for everyone with insight and knowledge to share and if you have other parameters that you know is important to consider please feel free to let everyone know.

Thanks/Michael
 
...Ok , well perhaps irrelevant...as its neither what you are looking for, but I imagine a load of folks haven't a clue how their boat is constructed....., but when I bought my boat I found this is how Hardy build all their range of boats, reading it still gives me a warm feeling that I have a well built boat..

"Initial lay-up Lloyds approved isophthalic gelcoat and resin. Subsequent lay-up orthophthalic resin. Stiffened with heavy GRP foam filled stringers and hand bonded plywood grid. Bonded waterproof plywood equipment beds and foundations. Hand bonded, resin coated waterproof plywood bulkheads. Solid bonded engine beds with integral plate steel mountings.

Superstructure

GRP with balsa reinforcing. Bonded waterproof plywood equipment beds and foundations.

Hull and superstructure are bonded and bolted together using stainless steel bolts to 10mm backing plates"

..good luck with your search!
 
Big subject! All those you mention build in quite a similar way, except that
(a) some spray the gelcoat whereas others brush it;
(b) sealine spray the glass whereas others use hand-applied matting (and most would consider matting to be engineeringly superior to spraying);
(c) Storebro use very high quality joinery and Jeanneau use very low quality joinery but that's reflected in price so all ok and anyway it's a separate issue from hull engineering. And there are other differneces in joinery: Sunseeker cover nearly all joints internally, even in full view on furniture, with a fine bead of silicone sealer. Fairline and Princess make the joints fit without silicone, And lots of other subtle and not so subtle diffeences along these lines.
(d) none uses cored hulls underwater, all use coring for decks, superstructure, internal mouldings (which is a good thing);
(e) none uses uber high tech vacuum bagging for layup;
(f) bavaria are the only ones to use a massive CNC cutting jig for the raw mouldings but that's a cost saving and not hugely relevant to the final build quality
(g) different builders claim different processes for shaping, sitting and attaching bulkheads but I'm not sure of the differences and which are better/worse.
(h) there is quite wide variation of both spec and quality of fittings, seats, internal linings, etc. Things like hp of bowthruster, quality of bought-in seats, quality of basin taps and WCs, quality of door hinges and catches, etc, varies widely from builder to builder.

Actually Firefly's quoted description of the Hardy (well known to be a very strongly built boat) could be applied to most of the mainstream builders too, except that most use plastic coring (divinycell, airex, etc) rather than balsa. Many folks I'd prefer plastic because coring can accidentally get wet which harms the balsa. I don't know about the 10mm backing plates and I'm wondering what dimension the 10mm refers to. Surely not thickness of the backing plates!?
 
Princess is jumping on vacuum bagging introduced on V78, 78 MY and I think they started on V62 too will be in all the range in a couple years time
following my few inspections, none of the above use Divinycell, Airex or Corecell
they use PVC but not any of the above, minus Princess as above using Divinycell also on bottom
Jeanneau and Beneteau have balsa cored bottoms with polyester resin
Sunseeker uses Isophtailic gel and vinilester resin, the deck of Sunseeker are vaccumm baged I dont know if it is so for all models, side of hull are balsa
Princess uses Isophotalic gel and Iso resin, and standard PVC
Fariline does not give much information on what it uses but my experience is Isophtalic with Mat, and vinlester resins

the reality is this
polyester - absorbs the most
isophtalic - half to polyester
vinilester - half to isophtalic
epoxy - the least absorbant of resins
 
Firefly625 said:
... but I imagine a load of folks haven't a clue how their boat is constructed.....,
Click to expand...

Maybe of interest and provides a bit of insight into how a grp boat is put together. An American manufacturer, but considered one of the better ones. Shows what a backing plate is used for on the hull / deck join as well! Seeing how Formula put their boats together certainly gives me that warm feeling of being on a well put together boat.

http://www.formulaboats.com/factory_tour.aspx
 
sorry, just re-read op's thread... so I stated./.."...Ok , well perhaps irrelevant...as its neither what you are looking for...." well of course Hardy do a 45+ flybridge of course.... the Hardy 50. opps, sorry...

PICT1153Comp.jpg


....and jfm, once again a clear indication of why I would never have a technical conversation with you, as very soon I would realise I didn't know anything...

.....oh and just one more thing, a friend saw a boat in a boatyard building last year at Hamble Point, it was just 9 months old, one of the fixing areas that bonded the hull to the topside had allowed moisture into the balsa core of the hull construction, they were taking off meter wide sections of hull and stripping the sodden balsa out, replacing the balsa and replacing the grp and they were going to do that to the entire boat.... horrendous!
 
Firefly625 said:
.....oh and just one more thing, a friend saw a boat in a boatyard building last year at Hamble Point, it was just 9 months old, one of the fixing areas that bonded the hull to the topside had allowed moisture into the balsa core of the hull construction, they were taking off meter wide sections of hull and stripping the sodden balsa out, replacing the balsa and replacing the grp and they were going to do that to the entire boat.... horrendous!
Click to expand...

I'm intrgued that balsa is still (apparently) used widely. I can't figure out why. Coring is cheap, relative to the boat cost, so why would any builder use balsa rather than a plastic coring? Anyone know?
 
The reason for the range was mostly to narrow down the build techniques, smaller boats can cut a bit more corners and larger ones can not so no problem.

How about the deck to hull joints on the different brands, I know some bad examples have only screwed them together, some have overlapping hulls with a polyurethane adhesive/sealer in between and I guess the best ones are built into one using fiberglass mat and polyester.
Commenting on the Formula video on this its probably better to have the backing plate on the inside but you still got the small screw head on the outside so you have an equally weak point as with no backing plate.

The other thing that I think is important is how they have gone about reinforcing the hulls integrity. On newer boats most use some sort of pre-molded inner lining to provide this. The challenge with this is to attached it to the hull, a really bad example of this is to use gelcoat filler which I've seen happen on slightly smaller boats a few years back. Then I've seen other bonding compounds that I am not really sure what they are made of but seem to work. You can see what I mean by looking at the structural hull matrix video on the Formula site.
I would assume the best is to fiberglass mat and polyester to build this in as an integral part of the hull but I am not sure anyone does this or if its even possible.
Then there is the more old fashioned way of adding stringers, liners and bulkheads that are built in manually with fiberglass and polyester. Not sure anyone does this anymore, some say the Bavaria's are build like this but I have not seen it.

I find it hard to believe that anyone uses pure balsa as coring in high stress places anymore, it may be that its better for insulation compared to the other options so still might make sense in hull sides etc.

I also find it difficult to get this type of information in a factual way, it's more word of mouth and anecdotal.

/Michael
 
if you want high quality plastic cores which are water resistant or repellant plastics are more expensive JFM, about double the price I guess
even in resins above Epoxy resin costs triple to standard polyester, while vinilester costs double
in balsa there is also the difference if you use end grain, and standard balsa
actually balsa above waterline I dont see so much of a problem unless someone does not drill a hole which he does not cover correctly, altough I saw horrific decks especially of some very well noted builder
coring in all hulls is starting to take shape now, and we will see some amazing QC stories along the way from many builders
LOL if builders complicated things with the standard method, wait to see this
 
yes Ben Vacuum infusion was invented in 1994 http://www.patentstorm.us/patents/7413694.html

the first builder that I know of using this system was Franchini in Italy, but I am sure some builder in the US was ahead of them in this method
Franchini used the patented system of resin infusion called Scrimp, and was followed by Pershing with the same system a year later I think it was 2000
Azimut started full resin infusion with the 47 in 2006, and Sunseeker resin infuse there decks since 2005
Sunseeker, Azimut, and Princess use the Diab - divinycell system
 
Hand laid-up, moulded fiberglass hull, deck, flybridge with core in decks and cabin top
Independent compartments throughout hull Isophthalic gelcoat exterior
Solid keel, chines and bottom
Layer of Kevlar chine to chine
Vinyl ester resin in first layer of hull
Watertight collision bulkhead forward
10 year structural guarantee
 
Some time ago, I found this catalogue, where most materials used in boatbuilding are shown, each with a brief but interesting introduction.
Also, on Professional Boatbuilder there are frequently very detailed articles on these subjects.
Though I must say that how can anyone compare Storebro with Bavaria and decide on the basis of how the hull and deck are joined, that's beyond me... ;)
 
What I find interesting is that many of us have strong views on which manufacturers have good, strong hulls and some others don't but not so many really knows why.

We are actually not considering any Storebro's, it was included as reference in the hope that anyone could share the specifics of how they potentially built much better hulls then some of the others.

Btw, in the unlikely event that anyone thought differently, the build parameters are obviously just part of many other considerations.
 
...not wishing to upset anyone, and I am asking the question as I thought I knew...but from this thread I am starting to wonder, is Bavaria a quality make? I thought it was on a par to Jeanneau...which of course is OK....but certainly not special as I always considered Storebro.
 
A_8 said:
What I find interesting is that many of us have strong views on which manufacturers have good, strong hulls and some others don't but not so many really knows why.
Click to expand...
Same reason why most peeps also have strong views on what the coach of the national football team should do!
Including those who never played football in their whole life, obviously... :D
 
PowerYachtBlog said:
yes Ben Vacuum infusion was invented in 1994 http://www.patentstorm.us/patents/7413694.html
Click to expand...

Umm, just being pedantic, Vacuum bagging was 'invented' some time before this patent was issued (the patent is for a double bag process), hence it is even more 'old hat'.

Green Marine in Lymington were vacuum bagging the hulls of the composite (kevlar, glass, epoxy) Mersey class lifeboats for the RNLI in the very early 90's before this patent was issued. The hulls were built in two longitudinal halves on moulds - one half at a time.
In summary, the prepreg cloth (already soaked in epoxy, and kept in the fridge) was laid out in the mould and then a vacuum bag was spread over the whole thing, and all the air sucked out. The hull component was then 'cooked' (at about Gas Mark 1..... :D) in a rather large oven.
Note that this is relatively simple stuff, and is different to vacuum infusion like SCRIMP.

Professional Boatbuilder has excellent articles about all aspects of boatbuilding - they are always on the cutting edge of technology - and a subscription is free!
Go on everybody, sign up!
 
jfm said:
Sunseeker cover nearly all joints internally, even in full view on furniture, with a fine bead of silicone sealer.
Click to expand...

I'm glad I'm not the only one to notice that. Not pretty is it
 
Firefly625 said:
...not wishing to upset anyone, and I am asking the question as I thought I knew...but from this thread I am starting to wonder, is Bavaria a quality make? I thought it was on a par to Jeanneau...which of course is OK....but certainly not special as I always considered Storebro.
Click to expand...

From what I've seen the older Storebro's are hugely solid boats, they will live for a long time with a bit of TLC. I've looked at and tested the impressive 435 commander but don't think its built as solid as the older ones but it still may be as good, just don't know enough about the details to really know. Which happens to be what this thread is all about...:)
I've also looked at and tested a few Bavarias and even if they are built in an "old fashioned" way, by some perceived as better built (because they can be more easily repaired!?) then some others I am not convinced they are. There are many aspect to building boats and progress is unavoidable, things get better but sometime it takes a bit of trail and error for new ideas and concepts to work really well.

The point is (partly) do we know, do we (on average) care or do we just fall for the best looking one within our financial range!?
 
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