transom depth, 15" verses 20"

[albonn]

hello every body,and thanks for your time and responce ,I have a 18' johnboat /flat ..using a builders square my transom depth is 17" deep ...yes positive ...old and VERY HEAVY would not a long shaft ....say 25/30/35/40 horse be a better length, what puzzles me is the 17" depth would 15"shaft be to short or viseversa 20" being to long with a one shotdeal on unknown motor ,but will be in the range of 25/40 horse.in a nutshell,17"transom with a 15" or a 20"shaft ...help!ps motor will be a tiller!

 

[Willyclay]

Re: transom depth, 15" verses 20"

If you measured at a right angle to the keel and got 17inches, then you do have an odd dimension. Take a look at the link below for a visual (the "e" dimension) of what I understand you to be saying. If that verifies the measurement, you may be faced with the options of cutting the transom down or raising the motor up, possibly with a transom bracket. A test mounting of a motor might answer the question more precisely. Good luck!

http://continuouswave.com/whaler/reference/engineMountingHeight.html

 

[Rancherlee]

Re: transom depth, 15" verses 20"

I know my SS 6hp evinrude actually measures 17" from the clamp to the cavitation plate. Every LS motor I've had is in the 21-22" range.

 

[bob johnson]

Re: transom depth, 15" verses 20"

if you measure the length on the transom( hypotenuse) then the measure will be longer than 15 "...although I wouldnt suspect 2" longer.

check out the long shaft motors you find...if they have several sets of mounting holes , you maybe in luck..IF in fact the 90 degree measure from the hull plane to the top of the transom is in fact 17"



if it is 2" long..I would think your suffer more with a short shaft, than you would with a long shaft

good luck

bob