How tall should a trailer be at the back?

I would like somebody to measure from bottom of their transom to the ground with trailer hooked to their truck and tell me what that measures.
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I dont want trailer so tall as to be difficult to launch and recover boat at the ramp.
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I am putting together a trailer to haul an old 14/36 flatbottom boat..What I have is a mis-match of parts salvaged from a boat trailer manufacturer that moved operations..The axle was 21 inchs too wide for the trailer- I narrowed and re-welded it. The springs that come with that axle seem to set the boat higher than desired..I dunno........Time to decide what size tires and rims to buy for it..Temporarily I've stuck a pair of 14 inchers on the trailer just to move it around the shop and obviously thats too tall.. Then again would rather buy 12" rims but that isnt just a whole lot shorter.....But before I go buy 8 inch tires I thought I would ask folks who know this stuff..
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Incidently I come into this from my very serious metalsworking hobby..I have 60 by 60 foot shop building with multiple full sized lathes and mills , grinders, welders etc....Til recently I been doing the hobby gunsmithing thing and now I am getting a kick from buying old rusted and busted outboard motors and rebuilding them..Yesterday I made new impeller for 1939 2hp Muncie ..Lot of fun working on the old motor, now I fixing up old boat to get me on the water to give this and couple other old motors a workout...I dont mean to give the impression that I know anything about boat motors but volunteer that I am having fun with what I am able to do and learning new stuff at every turn.....I am still looking for about a 10hp motor from the 1940s or 1950s.
Thankyou

I've got 21"

lckstckn2smknbrls said:

I've got 21"

Click to expand...

Thanks a bunch.. Mine measures 29" with the big tires on it..Now with your measurement shows me I am way too high and then finally I notice I am an idiot....I mounted the axle under the springs like my truck..But I see the couple trailers I have here in the yard have the axle placed over the springs..So I pulled the axle and set it 'right'.. So now with 12 inch tires I can get the bottom of the transom about 20 and 1/2 inchs off the ground.....Thanks lckstckn2smknbrls , now I can go buy some wheels..