Boat Design Forums  |  Boat Design Directory  |  Boat Design Gallery  |  Boat Design Book Store  |  Thanks to Our Site Sponsors
Old 08-30-2001, 10:45 PM
richard richard is offline
Junior Member
Join Date: Aug 2001
Rep: 10 Posts: 2
lapstrake in fiberglass

At the marina I've been seeing a couple of older fiberglass boats which have been molded to look like wooden lapstrake boats. Does this lapstrake construction in fiberglass have any function, or is it just for looks? Would a smooth hull or a lapstrake hull be better?
Reply With Quote
Old 08-31-2001, 07:43 PM
Scott Scott is offline
Join Date: Jun 2001
Rep: 10 Posts: 41
Just for looks, to emulate the wood boats that fiberglass replaced. I don't think it's done too much anymore. I am sure a smooth side is easier to manufacturer and maintain, and I can't see that the faux lapstrake adds anything - maybe a tiny bit of stiffness I suppose, but it's mostly done just for looks.
Reply With Quote
Old 01-11-2005, 08:02 PM
Bob Wickes Bob Wickes is offline
Junior Member
Join Date: Jan 2005
Rep: 10 Posts: 1
Location: Southern Chester Co. PA
Lapstrake in fiberglass boats


I own a KMV With 400 lapstrakes Norwegian utility boat. The lapstrake, combined with the hull farings combine to make this boat unusually dry in a choppy sea. The Norwegians were out to make an indestructible and unsinkable 14.5 footer (5"10" beam and 450 Lbs weight), and I think they succeeded. My only problem is that I haven't taken her out for two years. She just sits in the boathouse up on dry land.

Bob Wickes
Reply With Quote
Old 01-13-2005, 06:52 AM
Raggi_Thor's Avatar
Raggi_Thor Raggi_Thor is offline
Join Date: Jan 2004
Rep: 711 Posts: 2,457
Location: Trondheim, NORWAY
The "strakes" also add stiffness to the hull.
Regards, Kvedja, mvh,
Ragnar Thor Mikkelsen
Reply With Quote
Old 01-14-2005, 02:03 AM
PAR's Avatar
PAR PAR is offline
Yacht Designer/Builder
Join Date: Nov 2003
Rep: 3967 Posts: 17,895
Location: Eustis, FL
For a number of years I brushed off the idea that lap hulls were of any real advantage, other then knocking down some spray. I've since found they do seem to ride softer and surprisingly a bit faster, then a round or chined equal.

The lap in 'glass look never did come off right. They'd get the gains wrong or leave them off entirely and the crispness of the laps were not there, looking like way to many coats of paint or something.

I noticed the old Chris Craft, Thomson, White and Lyman hulls rode better. Must have been the extra weight of the soaked wood, right. Now that I've had much more experience with lap hulls, I've found they are light, not heavy. The 25' hardtop Lyman I just finished weighs in at 3,600 pounds and it rides like a dream. A chined version would pound the fillings out of your head in a decent chop. The 27' Chris I have has a real nice ride as well.

I've been able to ride in many lap hulls, several power and sail of differing sizes and accommodations. While sailing I noticed bubbles, lots of them. They are created as the laps move through the water. I don't know if they offer any cushioning, but something does. I've sailed lap and smooth hulled versions of the same design and the lap construction seems to have been just a touch faster. Maybe the bubbles do something to the boundary layer or act as water ball bearings, I don't know.

In wooden construction the laps form a longitudinal stringer at the meeting of each plank, making a strong structure. In 'glass you'd get a similar effect, sort of a 'glass angle iron at each lap joint.

In the end it's hard not to like the look of sweet curves, gently sweeping down the flanks of any boat. The laps make a nice sound when ghosting along and you'll find most folks will look over a lapped hull long before the plastic monoliths currently available.
Reply With Quote

Old 01-14-2005, 03:41 PM
gonzo's Avatar
gonzo gonzo is offline
Senior Member
Join Date: Aug 2002
Rep: 2031 Posts: 11,847
Location: Milwaukee, WI
It is possible to use a thinner skin. The laps are structural reinforcements.
Reply With Quote

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Similar Threads
Thread Thread Starter Forum Replies Last Post
help with fiberglass thicknesses on bass type boat mrbaseballny Fiberglass and Composite Boat Building 7 06-19-2005
08:39 PM 
Fiberglass filler/fairing alexhiguera Fiberglass and Composite Boat Building 1 01-30-2005
08:36 PM 
Wooden or Fiberglass berkin Boatbuilding 10 12-31-2004
02:42 AM 
Information Reqested Regarding Fiber Glass Boat Manufacturing sivaramakrishna Boatbuilding 9 08-25-2004
08:16 AM 

Forum posts represent the experience, opinion, and view of individual users. Boat Design Net does not necessarily endorse nor share the view of each individual post.
When making potentially dangerous or financial decisions, always employ and consult appropriate professionals. Your circumstances or experience may be different.

All times are GMT -5. The time now is 05:59 PM.

Powered by: vBulletin Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Web Site Design and Content Copyright ©1999 - 2017 Boat Design Net