Outboard Height on F-rib

[mm289]

So just following up on measurements and stuff. In the other thread @gurnard was mentioning about short shaft lengths being about 17".

So I set up both my Mariner 15HP and Mariner 6HP on the transom and measured from AV plate to top of mounting bracket, where it would sit if laying flush on the transom.

15HP was ~ 17 1/2" as below.


And 6HP is also ~ 17 1/2"




The challenge this creates is the Frib has a 15" transom so you are always around 2" deep on the AV plate.


Whilst I have been able to take out 1/2" on the 15HP with a raising block, the "throat" on the 6HP mount is not deep enough to allow for a raising block.


In practice this means the distance between the top of the mounting plate and where the mounting screws are is very small, so if you raise the engine the screws are clamping to high on the transom.


Now in reality this probably doesn't make much difference to performance, the 15HP still does ~ 20kn and I only use the 6HP for river work anyway.


It would be interesting though to compare "real" leg lengths on other short shaft OB's. If I was buying engines again I might be tempted to try and find an OB with a shorter leg length for a Frib


Cheers,


Paul.

[beamishken]

Lots of folk scream "dont do it" when anyone suggests cutting down a longshaft boat to fit a standard shaft engine but in reality its often the best way to match an engine to a transom
A 20" transom you want to hang a 17.5" leg standard shaft outboard on & run it an inch high to get better performance you'd only be cutting 1.5" out of the transom, far easier & better than trying to build up a transom from 14.5 or 15"
Only mho of course

[Locozodiac]

Just to know, are U trying to match the AV plate to be even with your boat's aft bottom independently if installing an S or L motor ?

Happy Boating

[mm289]

@locozodiac just trying to match to a short shaft, the AV plate is about 2" below transom bottom, but that is about as good as I can get it


So the polycarbonate plate didn't last very well



So wioll order up some MDPE or similar, but the block of wood will do temporarily


Cheers,


MM

[mm289]

And in other good news, we made it up to Scotland ok


Boat rigged and ready and took it out on Loch Striven for a few hours yesterday.





Cheers


MM

[mm289]

Just to update on the travel plans really, weather hasn't been great but we managed to explore Loch Striven then had a lovely day Tuesday going up the East Kyles of Bute to Tignabruich. The only really sunny day we have had but it was great
Loch Striven



Loch Riddon, with loads of jelly fish - some of them quite large






Stopping off opposite the Burnt Isles on the North East tip of Bute






Weather looks good for tomorrow so might try to circumnavigate Bute clockwise - but will see what the sea state is like when we get out towards Rothesay as we are on our own so will be fairly conservative


Cheers,


MM


with loads of jellyfish - some of them quite large