Scaling boards - need experienced help

If I scale a board up (say from 6’3" to 6’8") and adjust the width of the board to match the Greg Loehr technique (for every inch of length increase width by 1/8") should I also scale the position of the fins ?? I have actually already done this and the board seems to surf well, but I am not sure if this is convention. Also if the 6’3" had a certain rocker how does this rocker translate when the board is made at 6’8 ?? Do I keep the original nose and tail lift in which case the overall curve flattens and elongates ? Or do I scale the entire curve so that the nose and tail ift increases proportionately. help!

Guys, Im desperate for help in this department. Help!

Your fin position sounds right. mine are set at 3 5/8 and 11 5/8 on my 6’8". Scaling rocker. Take any measurement off your rocker then divide by by length, then multiply that by the new length. Also if your board rides well then dont sweat it.

what’s a cubit? Bill Cosby transchanneling Noah 1965?.. ambrose…c.a.d.? …

only scale if the board is for another person i tend to scale 1/4 "for every 1"of length (eg 6’-4"x19 = 6’-8"x 20 )you scale up for bigger guys scale down for smaller guys if the board is for the one person and its part of a quiver then generally widths stay the same and only lengths change to straighten or curve the outline to suit different size waves … reards BERT

answer to fin question is if its part of a quiver for bigger waves leave the fins or move them back…if its a board for a bigger guy in small waves move the fins to scale i like like to run 13 and 5 for bigger guys in small waves on 6’-8" to 7’-6"

In my experiece 1/4 inch would be too much. 1/8th was derived by using 6’x18 as one end of the scale and 9’x22.5 as the other end, both standard, traditional measurments. Divide the 4.5 inch difference in width, by 36 inch difference in length, and you get .125, 1/8 inch. This makes the rail to rail transistion similar in every length throughout the scale. Rail to rail is the constant that must be kept in any design. Using 1/4" your 9 footer would be 27 inches wide. In other words, at 1/4 rail to rail slows as you increase length.

yep greg your right there…i only use that scale to about 7’-6" max and only in relation to small waves, so a 20 stone guy can still get a good small wave board coz the curves are proportionate to a smaller guys small wave board …18 is 1/4 of 6’ a length to width ratio of 1to 4 which is perfect for small wave curves, thats why i said use that scale if its for a bigger guy for small waves…as a point of interest im finding a lot of older short boarders are really enjoying the same boards that work well for 15 to 16 stone younger guys that im building them for small waves using the 1 to 4 scale … regards BERT

Yes Bert, I straight scale (that’s the 1-4 you were talking about) everything but outline. For rockers and even thickness. With outlines I start with whatever the original board width is and scale from there. In other words a 6’ fish may be 19 1/2 inches wide and to scale I just start there and go 1/8 inch per inch for bigger guys. So a 6’6 would end up being 20 1/4". As you said, for bigger guys who want to ride short you have to put the volume somewhere and width and thickness are the only choices left so…