Need Help with Venture 23 Boat Lift Bunk Specs/Hull Deadrise

S

SEdowneast

New member
Hello Everyone, well I guess I will be part of the group in earnest soon, as we’ve just ordered a new Venture 23. Very excited about the adventures ahead!!

I will need to get my boat lift bunks built for the new boat and am looking for the specs for them. If anyone with a Venture 23 could help, it would really be appreciated.

I am specifically looking for the deadrise angles for the hull at the stern and the angle of the hull directly below the front of the midship cleat. The “level” tab of the “Measure” app on an iphone can be used to take angle measurements.

I am also looking for the centerline distance between the bunks if someone has those….or, even the same measurement of the back bunks of a trailer that has been set up specifically for a Venture 23.

Look forward to being active with the group in the future!

Thanks so much!!
 
Have you tried contacting NMI (Northwest Marine Industries) that is building your boat? I am sure they have all these technical specs since they set up the trailers for these boats as well.
 
I have asked the questions via the dealer but haven’t gotten a response yet. I think they are quite busy these days! Thinking someone on here might have already been down this road, this my post. Thanks!
 
Interesting questions: are you going to change the angle of the boat surface (upper surface), by the angle of the deadrise of the various stations in the hull. I am not sure I have ever seen that done. Certainly now many of the lifts are fitted for the deadrise aft--this is especially important in high dead rise boats, such as Contender (up to 26* at the transom.

I have a 25 year old lift, which I have put boats from flat botton, minimal dead rise, a 27' boat with 18* deadrise, a several 20 foot boats with 18 to 20 degree deadrise at the transom, and two different catamarans on--all the same: two 2X10 true dimensional salt water treaded timbers on each side. They have remained the disance apart most of the time--and that was for 8' beam catamarans. I would have had to build (custom wood work, which I would do my self with a power planer) for each boat doing that. No ill effects on any of those boats from the way the bunks were set.
 
Well since the deadrise of this boat progresses from somewhat flat, say 6 degrees at the stern, to much more towards the bow, I generally bevel the edges of the wood bunks to similar angles. By doing so the boat will sit flat and is fully supported by the entire portion of the edge not just maybe a corner of the wood bunk. It’s not hard to do if you know what angles to start with and finish. Additionally, you can look at the trailer bunks to see where the increase in angle begins as you move forward. Of course on most boats the stern Deadrise is carried all the way forward, but not on C Dorys, thus the information request. Thanks!
 
If you have the skills to do what you propose, then go for it. Hopefuly you have a power planer, or even a good draw knief and long planes. Even the extreme deep "V" boat have variable deadrise. The early C Dory had flat bottoms. Many boat trailers have the bunk boards flat, but they articulate and then they twist and presume the proper angles, Forward bunks resume the proper angle, as their mount moves. One could do the lift bunks the same way, but that might bring the bunks higher. How much water under your lift? You want enough so you can float the boat off in even the extreme low tides.

I see lots of new boat trailers, which have a constant deadrise built into the lumber set on edge, but it is not variable. So there is compromise. The most weight of most small outboard powered boats is concentrated at the stern. So these trailers concentate on the stern deadrise. (Where the "deadrise" is measured in the "specs" on boats is noted.)
 
....or if this helps...The bottom bunks are 12' x 6 " and separated 32" apart at the transom, having a 4 degree deadrise. The bottom of the hull remain totally flat at 0 degrees up to about 7' where the angle increases in about 1 degree increments up to about 4 degrees at the end of the 12' bunk. These measurements were taken with my iPhone. Hope this helps and congratulations on the purchase of your new 23 C-Dory Venture and joining the group.
 
Such great folks and valuable insight on this forum!! So appreciate it!

For my boat lift I will basically rip the bunk boards with a circular saw at the required angles. The boards stand up attached to the beam brackets. Not really hard to do as long as you know what angles to cut.
 
How can you vary the angle of cut of the boards on a table saw? I guess it might be easier with a radial arm saw, but ripping with a radial arm is above my pay grade. --maybe the rough angle, but a power plane or draw knife/long plane is a better solution. Are you going to rip at a single angle, or vary as the boat's deadrise varies? If at the same angle all along the board, then the ripping is the best way.

Daybreak, is the deadrise 4* at the transom, and then transits to 0* a bit further along the botton? If so, the bottom has been distorted from the original manufacture?? Or am I miss reading what you posted. I was under the impression that the deadrise of the Venture boats was greater than the 22, and that was the reason it ran better into chop.

We know that the 23 has more deadrise than the C Dory 22. In the past I have measured the deadrise of the C Dory 22 at 2 to 3 degrees, running about the same until it gradually increases near the helm area. My own posts are the ones on deadrise in other places on the internet, and I had not measured the deadrise at variable stations.
 
thataway":1nyo8pop said:
Daybreak, is the deadrise 4* at the transom, and then transits to 0* a bit further along the botton? If so, the bottom has been distorted from the original manufacture?? Or am I miss reading what you posted. I was under the impression that the deadrise of the Venture boats was greater than the 22, and that was the reason it ran better into chop.
Click to expand...

Hi Bob,

The degree measurements I was referring to was only pertaining to the surface area of the bottom of the hull as it rested on the 12 ft. long 2 x 6 carpeted bunk. The 4 degree deadrise was measured while I was sitting on the concrete floor at the transom looking forward and this applied to the angle of the hull surface resting on the bunk. The next measurement was taken at the same elevation but on the starboard side of the boat. From the transom end forward, to about the 7 ft. mark, the bunk was relatively flat in relation to the boat resting on the bunk and being perpendicular to the concrete floor. At about 8 ft. forward from the transom end of the bunk, the bunk angle started raising away from the concrete floor in about 1 degree increments for every ft. of travel until it reached the 12 ft. mark and the end of bunk. At 12 ft. I measured the angle to be about 4 degrees in relation to rising up and away from the concrete floor. Keep in mind that I made these measurements for a small area of the boat as it rested on the trailer, behind the midship cleat to help SEdowneast with his original question. Hope this helps. Thanks Bob.
 
Thataway, I use a circular saw and do the ripping of the board as its laying on its side. The saw can be adjusted for angle of cut and has a gauge so you know what the angles are. Of course the blade is 90 degrees when straight up but the angle decreases as the blade lays down and the base sitting on the board remains flat against the wood. I’ve done this multiple times for different bunks for different boats. It’s probably +/- a few degrees, but you can sand the edge down to get the angle exact angle you’re looking for.

So on Gary’s measurements, I take it to mean that the dead rise of the hull at the stern is 4 degrees with it starting to progress at 7 feet and ending up at 8 degrees at the end of the trailer bunk. I will say I expected it to be 6 degrees at the stern and progressing to about 10-12 degrees. But I’ve never taken the measurements. Thankfully Gary was kind enough to do this.
 
SEdowneast, believe me I probably have been using a circular saw (more than 75 years) as long as you have been alive, My comment was that you implied that you cut a varying dead rise angle on a circular saw, which I think is close to impossible--but you could cut, for example only, you could cut 4* for 3 feet, then stop, readjust the saw blade to 5*, cut 2 feet, increase the blade angle to a 7* (because it was 1* per foot, or cut a foot at 6*. That brings up a number of issues with the saw and blade, and it is not a smooth transiion.

What you propose, a gradual transition is best done on a large band saw (similar to the 24" bandsaw, I owned at one time when we owned a boat building company), with a large band saw you can cut that varying angle smoothly.

You are going to sand the amount to make the smooth transition: OK maybe with a 1 1/2 hp 7" angle grinder/sander, which I have to assume you have. (I have two), as well as 2 4" angle grinder sanders.

A power plane is faster and more precise. Next down would be the long plane, (I have from 2" to 24" length planes, which are joys to use. Finally the draw knife--mine is over 100 years old and still cuts like a champ.

For those less experienced C brats, usually a boat lift bunk is a thick board set on edge, Vs the usual C Dory trailer where the bunk is set on its side, so the full width is supporting the boats bottom.

In any case, it would be a service to all of the C Brats if you documented how you do the bunk board in a tutorial and post it on the site.

Thank you,
 
Thataway, my apologies! From your post it didn't seem to me that you would have considered a circular saw as an option. Thus, I was just outlining the process I go through.

Your experience with all this certainly stands out to me, as your description about how to do it with a circular saw is dead on the money! You’re exactly right in that the transition to the angles is not easy at all. As you pointed out, there would definitely be sanding/grinding or the like involved!

My intention is to have the boat snug on to the bunks. However, with the relatively flat angles of dead rise on these boats where the bunks locate, I’m not sure that nailing these angles is even necessary. Probably could cut the whole bunk at 6 degrees and call it a day. Do you think that would suffice? Would love to hear your thoughts on this.

Thanks so much!!
 
I would cut at one angle--for the entire bunk. The fiberglass hull if well designed does well with. relatively small areas of support. I measure angles with several different wood working instriments, and a level, rather than using an I phone. I feel you get better resolution of the problem. There is the option of using basic Geometry the old fashioned way. There are even web sites using AI to do the calculations.

SEdowneast has the experience and knowledge to contribute a lots of information to this forum, and is a very welcome addition to C Brats! We have corresponded via private message, and he is well qualified.
 
Thanks Bob, I think I’ll follow your advice!

One average angle for the duration of the bunk sounds like the way to go and certainly the simplest! I too agree that the hull of this boat is strong and should be well supported using this method.

All great info and very much appreciated!!
 
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