Looking for Air Draft figures for NH

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Duke 239

Veteran Member
Joined
Sep 21, 2022
Messages
55
Vessel Name
Banna Strand
Vessel Make
Seadoo Challenger 230
I am searching for a loop boat. I am having poor luck finding air draft numbers for NH boats. I know the new 59CP is short enough (because I saw a video of it passing under that bridge in CHI, not because I have seen an actual height spec) but I am curious about the 43, 52, and 57. Does anyone know these numbers? They are not typically shown on listings, nor on NH’s web site.
 
I haven't seen them published either, but I think all of them require special attention and articulating stack of some sort to get under the bridges of teh Great Loop, etc. The exception might be the 41.


Do you have a link to the picture of the 59CP going under the bridge? I wonder if you can see whether the stack folds down, if it's optional, or standard? The few boats I'm familiar with were build with custom folding stacks.
 
It took me a while to realize you weren't talking about New Hampshire boats. I can guess what the abbreviation might be, but those few seconds you saved not spelling it out isn't going to help you attract the attention of people who might have an answer.
 
He did post in the “Nordhavn” sub forum. So id say figuring out the NH abbreviation shouldn’t be that difficult.

52s definitely need a folding stack.

CaptTom said:
It took me a while to realize you weren't talking about New Hampshire boats. I can guess what the abbreviation might be, but those few seconds you saved not spelling it out isn't going to help you attract the attention of people who might have an answer.
Click to expand...
 
They have very detailed line drawings on their website. With some precise measuring and basic math I'm sure you could come very close to the actual air draft.
 
Benthic2 said:
They have very detailed line drawings on their website. With some precise measuring and basic math I'm sure you could come very close to the actual air draft.
Click to expand...

I’m an engineer. We are taught early on “never scale a drawing”.
 
CaptTom said:
It took me a while to realize you weren't talking about New Hampshire boats. I can guess what the abbreviation might be, but those few seconds you saved not spelling it out isn't going to help you attract the attention of people who might have an answer.
Click to expand...

OK, does New Hampshire make a 59CP, or anything similar? Do they publish their air draft specs?
 
Just for future reference it is better to spell something out the first time you say it ever if it is obvious to you. Not everyone recognizes every abbreviation. After you have spelled it out once then abbreviations are easier to understand.
 
Duke 239 said:
I’m an engineer. We are taught early on “never scale a drawing”.
Click to expand...
I am an engineer and that is what boat line drawings are for. Any published bridge clearances are not all that accurate as every boat weighs a different amount and has different equipment installed up high.
The clearances you find under the actual bridges can also vary a lot from the published heights.
You have to measure the boat that you want. Put a lazier level on top of the flying bridge windscreen and run a tape measure down from the lazier spot to the water. Best accuracy you will get.
If you do get published bridge clearances, make sure you know what reference point on the boat they are using for the measurement. You might find yourself removing a bunch of stuff to get under.
 
BTW- most New Englanders call that state new hamster.


Grp hulls are semiporous. Older ones generally weight more. Between infill, fluids, spares, tools, stores and so many other things airdraft of two sister ships may be different. Generally do a actual measurement with tanks full, at 1/2 and 1/4. NT published all dimensions for my boat. None match reality. Difference is in inches. But for bridges sometimes inches matter. Suggest whatever numbers you get from whatever source will be estimates. Probably sufficient for a go/no go decision for purchase. However would confirm with direct measurements.
 
Duke 239, you can look at this from a different perspective given that you will find the published numbers. Do you rule out a boat that is close that checks all the other boxes?
That is where the engineer in you should kick in and explore the boat you want in person. Put the lazier level at different places on the boat and measure beam to water to determine how much work it will be to get the height down and what is the margin after doing that.
I definitely want to go under the 15'6" bridge on the Erie Canal. I know that the Bimini will have to come down and quite possibly the windscreen and the windscreen top rail. I can fit with those removed and I know how much work it will be. To me, doing that work is worth it to cruise the western half of the Erie canal and avoid the Welland Canal.
The work can be done the evening before I encounter the bridge. I likely will still run a spinning lazier level just above the highest thing on the fly bridge and see if I paint the bridge before getting to close.
The only snag in my plan is these low couple of bridges are between two locks that includes the Genesee river and a lot of canal. If the river is up, the clearance will be below the 15'6" bridge that is isolated between locks. I could end up waiting a while for the water to drop.
 
PierreR said:
Duke 239, you can look at this from a different perspective given that you will find the published numbers. Do you rule out a boat that is close that checks all the other boxes?
That is where the engineer in you should kick in and explore the boat you want in person. Put the lazier level at different places on the boat and measure beam to water to determine how much work it will be to get the height down and what is the margin after doing that.
I definitely want to go under the 15'6" bridge on the Erie Canal. I know that the Bimini will have to come down and quite possibly the windscreen and the windscreen top rail. I can fit with those removed and I know how much work it will be. To me, doing that work is worth it to cruise the western half of the Erie canal and avoid the Welland Canal.
The work can be done the evening before I encounter the bridge. I likely will still run a spinning lazier level just above the highest thing on the fly bridge and see if I paint the bridge before getting to close.
The only snag in my plan is these low couple of bridges are between two locks that includes the Genesee river and a lot of canal. If the river is up, the clearance will be below the 15'6" bridge that is isolated between locks. I could end up waiting a while for the water to drop.
Click to expand...

Pierre, great idea about having a laser level on the boat, they have become very inexpensive lately. For me, I am still searching broadly, so there is not an actual boat to consider yet. When there is, I will take your advice and do actual measurements.
 
bkcorwin said:
He did post in the “Nordhavn” sub forum. So id say figuring out the NH abbreviation shouldn’t be that difficult.

52s definitely need a folding stack.
Click to expand...

You don’t know which sub section it’s in when you start by “todays posts.” As I do, so it’s not obvious without carefully looking. I didn’t know initially either.
 
bowball said:
You don’t know which sub section it’s in when you start by “todays posts.” As I do, so it’s not obvious without carefully looking. I didn’t know initially either.
Click to expand...

Thanks for the insight. I assumed the way someone would see my post is to look at the Nordhavn section, but clearly there are other popular ways to browse the posts. Plus, I am used to posting on THT, and those guys would never admit to any lack of understanding of anything.
 
Air Draft

Interesting that you mentioned, "I saw a video of it passing under that bridge in CHI". I'd be interested to know which bridge. The Lake Shore Drive bridge, which is the 1st bridge past the lock is probably 18' as are subsequent bridges.

We are 17' and slipped under and I was scared in doing it.

I can't imagine any NH (I thought New Hampshire as well) getting under the DOWNTOWN bridges. The Sanitary Canal is made for bigger boats.

Now, that said and keeping in mind the NH is a very creative company in building boats and seeing a Fleming 55 on the NY Canals at Whitehall it can be done.

The Fleming had a bridge that would drop down into the boat, allowing it to slip under the 17' bridges on the Champlain Canal.

NH could build a boat that could first drop its mast and then drop other parts to get under bridges.

That also might be why you can't find air draft figures. IF a NH is customized for its owner it won't fall into the 'norm'.

Find your boat and go from there. There are a number of ways to do the Loop so you can usually find a way around.

BTW, we should finish our 8yr Loop this yr.

Good luck.
 
Nepidae said:
Interesting that you mentioned, "I saw a video of it passing under that bridge in CHI". I'd be interested to know which bridge. The Lake Shore Drive bridge, which is the 1st bridge past the lock is probably 18' as are subsequent bridges.

We are 17' and slipped under and I was scared in doing it.

I can't imagine any NH (I thought New Hampshire as well) getting under the DOWNTOWN bridges. The Sanitary Canal is made for bigger boats.

Now, that said and keeping in mind the NH is a very creative company in building boats and seeing a Fleming 55 on the NY Canals at Whitehall it can be done.

The Fleming had a bridge that would drop down into the boat, allowing it to slip under the 17' bridges on the Champlain Canal.

NH could build a boat that could first drop its mast and then drop other parts to get under bridges.

That also might be why you can't find air draft figures. IF a NH is customized for its owner it won't fall into the 'norm'.

Find your boat and go from there. There are a number of ways to do the Loop so you can usually find a way around.

BTW, we should finish our 8yr Loop this yr.

Good luck.
Click to expand...

Congrats on approaching the finish of your long loop! The boat was the Independence, https://nordhavn.com/the-great-loop-aboard-independence/
The bridge was the 19.8' one that represents the absolute max for any GL ("Great Loop") boats. All they had to do was fold their radar arch, but I think the 59CP has underwater exhausts. I agree that buying a new Nordhavn ("NH") I could specify what I need, but I'm not buying a new one.
 
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