Boat owners- garage question

[The Evil Twin]

Seeing as my racing days are numbered; thinking about getting back into the boat world. We plan on having a out building built for other reasons. Figure why not plan for the next toy. Pricing out things. I'm wondering how tall we will need the doors if we purchase a boat. I can't find a whole lot on line. If experience serves me correctly, overall height on a trailer would be bridge clearance + draft + 12" ? Am I close or way off?
I recall from previous boats that with the outdrive down, there is a few inch gap between the drive and the ground when the trailer is level.

 

[fried1765]

Seeing as my racing days are numbered; thinking about getting back into the boat world. We plan on having a out building built for other reasons. Figure why not plan for the next toy. Pricing out things. I'm wondering how tall we will need the doors if we purchase a boat. I can't find a whole lot on line. If experience serves me correctly, overall height on a trailer would be bridge clearance + draft + 12" ? Am I close or way off?
I recall from previous boats that with the outdrive down, there is a few inch gap between the drive and the ground when the trailer is level.

I would suggest 14' clearance.

 

[The Evil Twin]

I would suggest 14' clearance.

For what? Depends on the craft. Our old Mastercraft fit in a 7' door. Supra needs 8' with the tower. Cabin cruisers need more. Pontoons less.
Hence the reason I'm asking about measurements for a boat in a trailer.

 

[mcmxi]

Seeing as my racing days are numbered; thinking about getting back into the boat world. We plan on having a out building built for other reasons. Figure why not plan for the next toy. Pricing out things. I'm wondering how tall we will need the doors if we purchase a boat. I can't find a whole lot on line. If experience serves me correctly, overall height on a trailer would be bridge clearance + draft + 12" ? Am I close or way off?
I recall from previous boats that with the outdrive down, there is a few inch gap between the drive and the ground when the trailer is level.

My boat is a couple of inches under 11ft from the ground to the top of the "rocket launchers". It's a 20'-7" Robalo R200 sitting on a Coyote trailer. The motor that was on the boat last year is shown in the photo, but I installed a VF200XB a few months ago. As you say, with the engine trimmed all the way in (down) there's a couple of inches clearance between the ground and the skeg.

 

[mcmxi]

For what? Depends on the craft. Our old Mastercraft fit in a 7' door. Supra needs 8' with the tower. Cabin cruisers need more. Pontoons less.
Hence the reason I'm asking about measurements for a boat in a trailer.

Exactly! There are many variables so let me know if I can help in any way with specific measurements.

Robalo R200 specs:

Bridge clearance with T-top = 8ft-4in
Draft = 15in

So using your formula we get 10ft-7in which is very close to the height of my boat.

 

[imnukensc]

Depends on what kind of boat you're talking about. A 14' john boat and a 22' center console with a T top are 2 vastly different things. A boat on a trailer typically, at least where I come from, has the motor tilted up on a "motor toter" while towing on the trailer until it's parked or in the water or going down the ramp. In any case, when the motor is down it ain't dragging concrete or anything else.

 

[PoTreeBoy]

Seeing as my racing days are numbered; thinking about getting back into the boat world. We plan on having a out building built for other reasons. Figure why not plan for the next toy. Pricing out things. I'm wondering how tall we will need the doors if we purchase a boat. I can't find a whole lot on line. If experience serves me correctly, overall height on a trailer would be bridge clearance + draft + 12" ? Am I close or way off?
I recall from previous boats that with the outdrive down, there is a few inch gap between the drive and the ground when the trailer is level.

I think your calculation assumes the trailer carries the keel 12" off the ground? That sounds a little low for many trailers. Maybe 30" to give some clearance?

 

[mcmxi]

I think your calculation assumes the trailer carries the keel 12" off the ground? That sounds a little low for many trailers. Maybe 30" to give some clearance?

The lowest point of the hull of my boat (keel) is 20" from the ground, when on the trailer of course. I'm building a pole barn this fall and I'm going to have 14ft of clearance since I'm adding a radar dome this summer.

 

[The Evil Twin]

Depends on what kind of boat you're talking about. A 14' john boat and a 22' center console with a T top are 2 vastly different things. A boat on a trailer typically, at least where I come from, has the motor tilted up on a "motor toter" while towing on the trailer until it's parked or in the water or going down the ramp. In any case, when the motor is down it ain't dragging concrete or anything else.

They are different, but that's where the standard measurements come in.
Bridge clearance- from the waterline to the highest part of the craft.
Draft- distance between the waterline to the skeg of the outdrive (or prop with an inboard).
The sum of the two are the OA height from the bottom of the skeg to the highest point on the craft. Johnny, cabin cruiser, ski, cigarette.... it's all the same points of measurement.
And no, our last I/O boat was not dragging the skeg if the outdrive was down while on the trailer. But it was pretty close. Closer that 12" Wouldn't want to trailer it home that way. I'm figuring the draft +clearance + 12" is close to trailering height.

 

[The Evil Twin]

I think your calculation assumes the trailer carries the keel 12" off the ground? That sounds a little low for many trailers. Maybe 30" to give some clearance?

Not the keel. The keel is part of the hull. The skeg is part of the drive unit. Which (when the drive is down (OB or IO) is much lower than the keel. The prop and skeg have to be below the keel so that they remain in the water at speed.