DIY Dinghy Davit advise / ideas needed

ArtWallach

ArtWallach

Member
Sep 12, 2011
160
Lindenhurst NY
Boat Info
2000 Sea Ray 310 Sundancer
Engines
T300hp Mercruiser Inboards
I drew up plans for a davit that will allow me to have the dink launch and retrieve from the swim platform
https://scontent-lga3-1.xx.fbcdn.ne...=59e3b319e73510b52fead418f0d191a4&oe=58D5F91C
https://scontent-lga3-1.xx.fbcdn.ne...=0463c30ee161f414b416d42279a6dea7&oe=591402C6
https://scontent-lga3-1.xx.fbcdn.ne...=14398081b926a1a41c1ed95ae5daa1fb&oe=58DFAC56

Im trying to figure out how best attach it to the underside of my swim platform.
My goal is to attach two 2' x 1.5" SS square tubes to the underside of the swim platform (that a smaller tube slides into) without having any hardware or minimal hardware showing on the top of the swim platform. I'm afraid that just using a recessed screw or recessed bolt head will pull through the platform. I don't want a tripping hazard or anything that will interfere with the platform when the davit is not on the boat.
Any ideas?
Thanks
 
Last edited:
Looks nice. Your design reminded me of an earlier design I saw on a blog I was following a few years ago when Dale was working on his 340. Here's the blog address http://searay340restoration.blogspot.com Look at the July and October 2012 posts for more information and pics.
 
Thanks for the quick responses.
@Tom,
I saw Dale's post. I loved his davit concept, downloaded it, studied it and I've incorporated most of his ideas into my design. I just can't do them all since I can't machine and weld like he did. I had to adapt his and other concepts into something I can make with hand tools. I just don't have a great idea for the final attachment methodology.
 
You'll need some type of backing plate, a very large washer or square plate would do fine. Then use a button head screw, put the nuts on the bottom side under the platform.

https://www.boltdepot.com/Socket_button_head_Stainless_steel_18-8_3_8-16.aspx

Will be about as minimal as you could possibly get unless you route out the top of the platform and "countersink" the backer plate and screw head.
 
My platform has "stringers" under it for support running from the edge of he platform to the transom - they are glassed in and part of the platform. I know some older boats don't do this - and support the less ridged platform by using metal down bars......if your boat doesn't have the stringers....add them, perfect place to tie the mounts into
 
Your Davits are too far forward on the dinghy. All the weight is in the back. I would also question making the arms out of 1/2" starboard. That's pretty small. I used 1".
 
You are within driving distance of my shop, so if you want to come up one day, I can machine any specialty parts you need to get this done. I'll need to know what size and thickness material, beforehand, so I can have it in stock.

Dale
 
I would prefer the port davit arm being more to the stern of the dink, but the model Zodiac I have purchased has two rudder strakes that are depicted with the dark rectangles. I basically have two choices.
https://scontent-lga3-1.xx.fbcdn.ne...=65fa28fda94d8f84f34deb201225ef6f&oe=591B3E96
Sliding the dink on either fore or aft of the rudder strakes. If I put the davit arm aft of the strakes I have only a 2" margin of missing the dink transom when pulling it onto the swim platform.
If the davit arm is forward of the rudder strakes it is only 14" to the transom. The dink tubes going to the points are the vast majority of the overhang.
Since I'm using rubber wheels I think (hope) I'll be fine with the 1/2" HDPE. I used 1" on a rocket launcher table I made (replaces cockpit table when fishing).
https://scontent-lga3-1.xx.fbcdn.ne...=2ba8d0412b4bfbc3b46ca5c5b7a00ae2&oe=5914BEA3
https://scontent-lga3-1.xx.fbcdn.ne...=3b496a3ea9dc96ca24888c425fcb7ee4&oe=591CAA47
It is very heavy for its size.
 
Last edited:
Dale,
Thank you for your incredibly generous offer. We are about 120 miles (2-3) hours apart.
If it comes down to having to fabricate it would be worth the trip.
Thank you.
 
ArtWallach said:
I would prefer the port davit arm being more to the stern of the dink, but the model Zodiac I have purchased has two rudder strakes that are depicted with the dark rectangles. I basically have two choices.
https://scontent-lga3-1.xx.fbcdn.ne...=65fa28fda94d8f84f34deb201225ef6f&oe=591B3E96
Sliding the dink on either fore or aft of the rudder strakes. If I put the davit arm aft of the strakes I have only a 2" margin of missing the dink transom when pulling it onto the swim platform.
If the davit arm is forward of the rudder strakes it is only 14" to the transom. The dink tubes going to the points are the vast majority of the overhang.
Since I'm using rubber wheels I think (hope) I'll be fine with the 1/2" HDPE. I used 1" on a rocket launcher table I made (replaces cockpit table when fishing).
https://scontent-lga3-1.xx.fbcdn.ne...=2ba8d0412b4bfbc3b46ca5c5b7a00ae2&oe=5914BEA3
https://scontent-lga3-1.xx.fbcdn.ne...=3b496a3ea9dc96ca24888c425fcb7ee4&oe=591CAA47
It is very heavy for its size.
Click to expand...

Off topic, but that rocket launcher table for fishing is a great idea that I will be using, with some modification, on my 330DA for somewhat similar purposes.
 
Creekwood said:
Off topic, but that rocket launcher table for fishing is a great idea that I will be using, with some modification, on my 330DA for somewhat similar purposes.
Click to expand...
What you can't see from those pics is that the redesign now has a slot for a fishing pliers, a knife and a a small cheap cutting board in the center (that is replaceable), but I don't like to cut any messy bait on it. I have no cockpit carpeting or transom bench when fishing. I tie down a cooler on the swim platform as a live well. for a SeaRay Sundancer, it makes for a decent fishing platform.
 
How far down do the strakes extend? Do you have a picture? I would consider putting the rear support right in the middle of that area. Are you planning to leave the motor on?
 
I would question the need for rollers as well. Starboard on wet fiberglass is plenty slick. I would thing the rollers would actually make it harder to haul out from catching on the ribs on the bottom of the dink.

Not trying to tear your design apart. I'm just speaking from what worked for me. I had a 1998 290DA with a 10' RIB.
 
Last edited:
My rear davit arm was only a few inches from the back end of the dinghy hull. Just far enough to give me a little wiggle room when hauling the dinghy up on the davit. The last thing you want is the dinghy sliding too far forward and the hull slipping off the front of the rear arm. Now the tubes are caught in the arms of the davit and it's a pain to straighten out.

If your dinghy has a fiberglass hull I would omit the wheels. Fiberglass slides across starboard like ice. I would also consider moving that rear arm toward the back of your dinghy especially if you plan to leave the motor attached. You have to consider weight distribution, not length. All the weight is in the back. Make a cutout in the rear support that can go around the strakes and support on the hull.

Good luck and keep us updated. I hope I've given you some points to consider. Search through my old posts and there are plenty of pictures of how I made mine.
 
Last edited:
This is what came with the boat I just bought last month. They are pretty pricey to buy, but after looking at them in person they seem pretty basic and should be easy to use as a guideline for a DIY project. They slide in to Weaver Davit brackets that are mounted on the edge of the swim platform:

http://www.dinghyramp.com/dinghyramp-hd-slide-on-boat-lift/
 
magstang1 said:
If your dinghy has a fiberglass hull I would omit the wheels. Fiberglass slides across starboard like ice. I would also consider moving that rear arm toward the back of your dinghy especially if you plan to leave the motor attached. You have to consider weight distribution, not length. All the weight is in the back. Make a cutout in the rear support that can go around the strakes and support on the hull.
Click to expand...
My dinghy is not fiberglass.Its 100% inflatable. I may rethink the placement of the portside davit arm.
 
You must log in or register to reply here.

Forum statistics

Threads
113,117
Messages
1,426,454
Members
61,032
Latest member
Brock340
Back
Top