Gardner/Herreshoff 17' Rowboat 2nd Revision

[Clifton Brittain]

I have been in love with this boat for about three years. I have built only one other boat, an 8' pram using stitch & glue. It turned out okay, but I'd like to do something more traditional that is a little sexier.

I would like to build it using Tom Hill's method, but when I try to develop forms on graph paper using the half-breadths & heights, I don't come up with a very fair or consistent line. Introducing the diagonals makes it worse. The origins don't seem to make any sense at all.

I have also tried to blow up the illustration to life size, but in magnifying it, there is significant distortion (base line & center line are not at right angles and it gets worse after that).

Can anyone help me figure out how to make a mold to get started on this puppy?

Also, if Hill's technique is used, how many frames would be needed? I'd like to be light without being too flexy.

[MarkWoyWoy]

Clifton I'm no expert on this. I have just finished planking a small launch which I lofted in January this year. This was built using Tom Hill's method.

From what you are saying when you layout from the offset table the points are way off?. IMHO this can only mean that:

1) The offset table is completely wrong. You can check these back to the line drawing on your plans. You do have some sort of plans? Just scale the various points on the line drawings and check back to the offset table.

2) You are doing something wrong. When I lofted the launch on the first attempt I had it backwards, breadths instead of heights and vice versa. It was confusing as I had never done it before and I had no real text on it. I took a step back and thought about it for a while.

A lot of people say that the diagonals are likely to be most accurate overall because they tend to be the longest. In my case they were quite inaccurate, on close inspection of the station line drawings the diagonal didn't quite intersect the right angle. Also some of the other points were off by up to a half inch, I assume theses were measurement and subsequent scaling errors.

I chose to pretty much ignore the diagonals and went with the breadths and widths. It came out fair. The advantage of the stringer method is that you can shift things around, shim and trim the stringers before starting the boat. I spent a full day doing this and it came out fine.

Mark S

[ 03-26-2002, 12:23 AM: Message edited by: MarkWoyWoy ]

[PugetSound]

Clifton, from the way you worded your statement I get the impression that you were trying to scale up the lines drawing from Gardner's book using graph paper. That could work but it is full of pitfalls and is the least desirable way to do it.
Gardner gave you two sets of offsets: Hereschoff's and Gardner's modifcation of Hereschoff's design. The offsets are not corrected offsets and as you have already found out, scaling up using a photocopier results in highly magnified distortions (by the way, the distortions imparted by photocopiers is a deliberate design feature).

You may want to do some reading up on the subject of lofting, Woodenboat has several good books on the subject. What I would recommend is that you learn how to translate the offsets into the lines drawings (do not scale off the lines drawings) and then build a model. You can develop the proper shapes of the planks using a large scale (say 1 1/2" = 1'-0" or even 2" = 1"-0") model. The offsets table is fairly straightforward if you read it very very carefully. Just lay out the points and fair a line through them (it would be alot easier if you had a decent batten and at least 4 or 5 ducks). Don't try to connect all of the points because it won't happen. Once you are done, then record your corrected offsets (corrected at scale) and procede to full size.

[fergie]

I too have been nuts about this boat for a while. I got alot of great information from several nice folks from the TSCA group on this craft. I decided to loft for the forms several months ago. I used the Gardner offsets and don't recall having any really unusual results. I will have to look again but am pretty sure they came out looking like his lines in the book. Of course, I am no expert on lofting and haven't put them to use...yet.

[Tom Dugan]

Another thing to consider is that Hill's method is designed for glued-lap construction. I know this boat can be built glued lap, but you mentioned wanting a more traditional boat. If you intend on riveting solid planks, you cannot use Hill's battened form.

Just a heads up, in case you were leaning that way.

And if you are planning glued lap, the frame spacing will depend on your plank thickness. My Gardner books are home, so I can't access his scantlings. Someone else is sure to come along with advice here, yes?

-T

[JimConlin]

The Tom Hill construction method, with Gardner's station spacing of 1'4" and five planks per side should work fine, even if you get sporty and go down to 4mm ply. If you're at all confused about the technique, get the video from WB.

Nifty boat. Take your time and have fun.