motor mount

[adla]

ok - so i have really decided to crowd my transom with stuff. I bought a 5hp johnson and this motor mount:



here is the motor sitting on the old mount that held the electric:



The directions say to measure from the upper part of the prop case to the inside of the clamp - and then take off 2 inches....and then add 8.5 inches   ....so, then I took that measurement and taped a stick on the motor mount but here is where I get confused. It says on a sailboat that the mount should put the bottom of the stick right at the water line. I can't remember where the water line is on the weekender and my boat has been washed. Does anyone have an idea (roughly is ok) where the water line is at the transom?

And - My plan is to reinforce the transom with a 1inch thick 12x12 piece of pine on the inside (already cut and ready to go today) and then with a 1/2 piece of mahogany on the actual transom (outside) - otherwise the bracket hits where it shouldn't - does this seem like enough reinforcement?

yes yes i know it makes a mess of my transom on my little sailboat..but it will do wonders for my range and ability to sail on Lake Mead -(a very very very big lake known for its whimsical nature)...

any thoughts on this will be appreciated...i am determined to get it mounted and ready for sunday.

a.

[capt jake]

WL on mine is about 2" up from the bottom of the transom (at the corners).

[Oyster]

You do not have a normal sailboat.   But also you do not have a big rocker on the boat, like most production hulls, either. I will read your post in the morning as I am getting ready to shut the lights off. But in my opinion, and with your speed of your hull, its not going to make much difference about how high or how low you mount the cavitation plate. So pick about one inch lower than the stern bottom and let it rip. Thats my thought at this time.

[capt jake]

Like Oyster said, plus make sure you have adjustment to take it up or down.  When a member of the crew goes forward, my motor will come out of the water at times, then I lower it.  I mess with it a bit depending upon the conditions and the trip.

[adla]

Thanks John and Oyster -

John - i don't think my transom even sits in the water when i am in the boat  ???
i found this pic and it almost looks like my transom comes up out of the water - i have others that show it floating out of the water at the dock -




i wonder if part of this is because of the way cut the keel  -- and partially because i only weigh 115 lbs (give or take 5 pounds)....

i was thinking of mounting it a bit lower - because i can move the tilt with both a lever thingy on the motor and the mount itself moves up and down 8.5 inches with that motor (it weighs 37lbs) ...

thanks for looking at it again tomorrow Oyster - I appreciate your input on this.

[Dave R1]

Adla, you can see that my boat sits with the transom out of the water a good way when there's no one in it.


I'm not exactly sure but I think when there are two in the cockpit the waterline is up on the transom maybe an inch or two.

My motor mount is a little high for the shaft on the motor I have. If a 200 pounder goes out onto the foredeck while I'm sitting forward in the cockpit, part of the prop comes up out of the water. I need to change the mount but I need to change the mounting screws on the motor before I can lower it anymore.

Out of curiosity, did you check to see if the rudder would clear the motor before mounting it?

The whole setup looks great.

[Oyster]

Almost forgot where is the four legged ballast positioned? I think you have it all under control. If it don't work today, tommorrow it will work. Its all custom on these hulls. I have spent the better part of the week rigging a fancy dancy homemade rigging for a tabernacle for the boat. Its just too much work stepping the mast of this size, no matter how lightweight you try to make on that is almost free standing, as this new one is, too.

[adla]

SO - i think it is ok to mount it maybe 2 inches lower than the directions suggest....here is another pic of my transom up out of the water  



The 4 legged ballast is almost always in the cabin - she likes to lay with her head towards the cockpit. She does a good job of staying centered....and she  is nearly 200lbs....with her so central in the boat it helps when i climb on deck and do stuff...not as wobbly.


Dave - yeah, i was careful to check clearance with the rudder - that swim ladder looks close but it doesn't interfere at all. Before I get carried away and start drilling holes in my transom, i will throw the mast up so i can check clearance for the motor mount.

Do you think my plans to stiffen the transom are enough - 12x12 1inch pine and then a 1/2 inch mahogany plate on the actual transom. WHen I built morgaine I didn't like just the stringers and glue so each transom joint is glassed in and built up with mat and then had the real heavy weave 6 inches either way inside for strength and water proofing... I'm pretty sure it is bomb proof.

Oyster - The whole mast thing is an interesting factor....this mast i have when i first launched was so wet and heavy that i couldn't raise it myself even with the help of a rope - then it dried out (without a warp thankfully) and now i can easily lift it with one hand...i would eventually like to make a birdsmouth mast that is a bit taller with more room to spread things out at the top and run wiring for a light etc...i already have the ss cable for new stays...but it isn't going to be this season. building is fun but i want to go sailing...fishing...swimming...etc. and so does my dog. The heavy mast was a concern until it lost weight....it is a doug fir 4x4 and is so light after a year in the desert sun...it dried slowly because it was encaspsulated with epoxy and painted w/oil based paint. It gets beat up where the gaff jaws hit - i need to put leather on the jaws.


     the recurring theme -- the boat will never be done


a.[/img]

[kydocfrog]

There definitely is a trim change with a passenger. CGII sits up with the transom out of the water empty and, it  appears in at least one photo, with me on board by myself. (I do weigh more than 115... ). But I think that part of my steering problem might have been that with two on board the transom dug in a bit, putting that gap between the rudder box and stern deadwood down in the water and changing the flow a bit.

I used a similar motor mount. I reinforced the back side of the transom with a high density polyprop. plank  -- read one of those big high density white chopping boards from a kitchen store. Works like wood, stiff as all get out; absolutely rot proof. Seems to be working nicely.



Now if I could just get back on the water.

DocA

[adla]

plus, i think i got lucky - and this motor is a long shaft - the measurement from the mount to the cavitation plate is 17 3/4"....

.
.

a

[adla]

Doc Frog -

GoOod idea --- interesting concept "rot proof" - i like it
maybe it absorbs the vibration better too?

a.

[Oyster]

I used spruce for my mast. Its 3x 4 1/2, laminated, just a few inches under 18 feet. The mast needs to clear the large centerboard, when laying back, and I did not want a thwart seating foward, as I intend on building a working style cabin, one that is about 3/4 size of what a normal one should be in length. Instead of stepping it through the top of the cabin house, since the there is an open area foward of the mast step, around the coaming, the cabin top will have an opening on top in the area of the mast and a few foot aft of it. Foward cabin will be sealed, and on top of the end of the mast. I will make a canvas cover to cover the slot in the aft for bad weather, or for sleeping and keeping th bugs out at night.

What I wanted to do was to let the mast pressure also be in the mast step, at the bottom, relieving any real stress , and build the cabin as lite as possible, only for toilet and dry area for sleeping. So my tabernacle pivot point is at the front of the centerboard, rasied up with a stainless steel tabernacle that I got with my 27 foot box mast, and I sawed the bottom interior out of it, so the mast pivots through it and down into the step and locking into place.
All the pressure by the mast, is taken up by the high tabenacle and the foot of the mast, with simple side stays and foward one to the end of the bow sprit.


I have each end of the centerboard trunk all reinforced as in my 20 footer, and I can walk unobstructed along each side of it. The bench seats will also be all the way fore and aft on each side. Up foward, I built huge amounts of storage shelves in the vee area, all in place before I deck it over. I can get into the area very easily from under the high deck, and plenty of space along sides of the rigging. I hope this is not too confusing, as I know a picture is worth a thousand words, but for now, words have to do.

[kydocfrog]

I am hoping that the material will absorb vibration a bit better. I had originally planned to put a very thin sheet of rubber as a vibration pad between the mount and the outboard face of the transom, but couldn't find a suitable material.


DocA

[adla]

i sure hope i did this right - i am nearly ready to mount the motor mount.

i went to target and bought two $1.89 cutting boards - they make the perfect thickness for the outside...i cut the handles off and then tapered them - fit them to the outermost point on the transom and then drilled holes    i then fit the 1" backing board inside and marked those holes and drilled...with a little work on filling the old holes from the other mount and cleaning up the polypropene from where it melted as i cut it...i should be ready to mount the motor by tomorrow afternoon. I just hope it puts the motor far enough in the water.....we shall see.

a.

[Andrew_Butchart]

What I did in planning for my motor mount is to use two angle brackets salvaged off an old bed and bolt them to the transom.  They're pre-drilled to accept another piece and since they held me, they should hold a motor or boarding ladder

To re-inforce the inside of the transom, I just cut out 1 1/2" circles of 3/4" plywood and inserted a threaded insert nut.  "Hopefully" this should be strong enough.  I was going to go with a solid backer plate like what you are describing but was worried about getting it tightly fitted to the curve of the transom.