Haven 12.5 Question

[ddeaton]

Strip planking a Haven with 1/2 inch thick spruce and epoxy with no cloth over the surface. Is this a proper way to build a hull? My reason for asking is - one is for sale one state away from me, new build, never been in water. Price seems fair. I thought when you cold molded a hull, you need to apply some sort of fabric over for strength? I havent asked details yet, figured I would ask here first. What little I know is carvel and lapstrake.
Thanks,
Danny

[David123]

Cold Molding does not necessarily call for glass cloth. Some use it some don't. Is this boat strip planked or cold molded? Cold molding is usually several layers of thinner stock placed over the building forms at opposing angles for strength. Strip planking is exactly what it implies. Strips of wood butted against each other with glued / caulked joints from the Keel to the sheer.

You would need to know from someone who has plans or has build one if the 1/2" dimension is heavy enough for the design. I don't know what the design calls for.

[ddeaton]

This boat must be strip planked. He said .5 thick spruce. Glued joints. Is spruce commonly used for this type of planking without cloth? Spruce is not the most rot resistant wood around, and what about wood movement? My concern is - without cloth to hold all together and only glue joints, what will keep joints from opening up later and rot setting in? I am thinking of driving 5 hrs to see this boat and want to do some homework before doing so. I am leary when a boat is built other than design.
Thanks,
Danny

[Brian Palmer]

Is it in PA or IN?

I'm near Harrisburg, PA.

-- Brian

[ddeaton]

Michigan, near Flint

[David123]

This site may answer some of your questions

http://www.havenbuilders.com/

and the cloth doesn't necessarily hold the boat together. It just adds another layer of abraision resistance. In a Stitch and glue construction, the cloth does add some strength to the whole setup, but in a Haven, the cloth would be primarily for abraision resistance on the bottom. The buildig process, done correctly is what keeps the boat in one piece.

Some strip plank boats are also edge fastened along with glue in the seam. The strips are sometimes bead and cove design to lessen fairing and gaps in the planking.

Go to the library and see if you can find Steward's "Boatbuilding Manual" which explains the different methods.

Steward lists spruce as a light wood and typically used in boat construction where weight is a factor and recommends it for framing cabin tops and such. Cedar is actually heavier than spruce.

Good Luck!

[ddeaton]

I understand the reason for the cloth. What I dont understand is using 1/2" thick spruce edge glued and screwed, then fairing and painting. What happens when the spruce expands and contracts, causing hairlines in the glue joints? The water soaks into the spruce, which is low rot resistant, and starts the process. Explained to me from the owner, the edges of the planking are butt joints, glued and screwed, not even bead and cove. This is a boat that will be moored on the water, not trailer sailed. A trailer boat I would not be so concerned about. I know enough to be dangerous here.
Thanks,
Danny

[Dave Gray]

Danny, I have no experience in the matter so I can only filter what others have discussed through my cloudy mind. I have read posts from people who have strip planked boats, edge butted, have not used fiber glass, and have never had an issue after 20 years with a boat in the water most of that time. Other folks talk about sheathing in and out with fiber glass to get a wood cored boat. Discussions have raged about water movement through a boat so sheathed and the possibiltiy of hidden rot or soft spots, much as in a regular fiberglass boat.

I wish I had paid more attention to the Garden Eel I saw at Schooner Creek Boatworks a few weeks ago. It's name was ODALISQUE, was an open boat (no cuddy), and built strip plank. I believe it was sheathed and finished bright but (damn it!) I didn't have my camera with me at the time so I don't recall if it was sheathed or not.

Certainly you will find lots of different opinions and attitudes on strip planking and sheathing. You might want to visit Paul Gartside's page to read his take on it.

Good luck and hope the Haven works out for you.

[RodB]

This is an interesting thread. It will be interesting to see what you find when you talk to the builder and what his build procedure is... is it strip or strip/cold molded...?

Is this boat to be trailered? Since it has a centerboard, I would presume that it likely would be...

The scantlings need to be checked... and considering what you have said so far, I would think sheathing both inside and out an approach that would result in a solid craft that would last many years trailered.

MacNaughton's scantling rules for "sheathed strip construction" could be followed which would call for sheathing with proper thickness of cloth both inside and out... the fiberglass cloth plays a structural part in the hull and offer lots of protection to the strips. Considering the wood selected for the strips, I would think encapsulation would be a good approach.

Perhaps you may find out that the building procedure still calls for a couple layers of 1/8" veneer.

Keep us posted.

rb

[John Gearing]

Back in the old days, as I recall, strip planking often didn't use glue at all since there were no waterproof glues to be had. Maybe a bit of red lead paint beween strips. But, the strips were all edge nailed together as well as being fastened to the frames. Remember, trailer-sailing was uncommon in those days. Most small boats built were kept in the water for the whole sailing season. Hence drying cycles were minimized, and any gaps that opened over the winter would eventually swell shut when the boat was re-launched in the Spring.

Jim Brown of tirmaran fame makes the point that dry wood that is epoxy-encapsulated stays dry. The trick is to keep it dry (i.e. keep the water out). His idea is that you can use wood species that are less rot-resistant if you encapsulate. Applying this idea to strip planking, you would epoxy the strips together, perhaps with edge nails or wooden dowels, coat the strip ends before they were covered, and then coat the hull inside and out with epoxy. The strips would then be encapsulated and rot inhibited, thus allowing for the use of a wood such as spruce which is not a desireable planking stock in general. Also, if the planks are encapsulated, there is no shrinking/swelling cycle such as you are concerned about. Thus, no glue line failures, joints opening, ribs breaking, etc. But if encapsulation is breached, you've got to get the water out then re-encapsulate. This would be a decent reason to put cloth on the outside, so that if you have an "abrasion incident" it is the cloth that takes the scrape instead of the composite layer beneath the cloth. I'll bet this is how the guy in Flint is doing it.

[paladin]

If the boat is strip planked using epoxy and 1/2 inch spruce the hull would meet Herreshoffs original scantlings, which were 1/2 inch cedar carvel....this would presuppose that the builder used a series of frames and not merely the station molds.....the hull would be heavy enough and probably rigid enough but the hull would definitely not take any appreciable dinging...The epoxy will provide the seal but absolutely no abrasion resistance.