Dinghy davits and lifts?

[Alaskan Sea-Duction]

The swim platform was also beefed up.

 

[bligh]

Here is a pic of my set up. Worked great all summer long in the Inside Passage.

That is a sweet davit system. How do you keep your dink from flopping all around in heavy seas, especially if your trawler is rolling? I took my davit system off because the dinghy was flailing all around if my boat was rolling. My davits weren't as heavy duty as yours, but I did notice quite a bit of movement where the dinghy would work itself side to side and I was sure something would give way or a pontoon would get chaffed through. Maybe I need to relocate the lifting eyes to create more of an angle side to side to prevent my dinghy from swaying.

 

[Alaskan Sea-Duction]

That is a sweet davit system. How do you keep your dink from flopping all around in heavy seas, especially if your trawler is rolling? I took my davit system off because the dinghy was flailing all around if my boat was rolling. My davits weren't as heavy duty as yours, but I did notice quite a bit of movement where the dinghy would work itself side to side and I was sure something would give way or a pontoon would get chaffed through. Maybe I need to relocate the lifting eyes to create more of an angle side to side to prevent my dinghy from swaying.

The dink naturally sits in the curve of the davit. I also use cross ratchet straps to suck it in nice and tight when I am on open ocean. Most of the time it just hangs and I can have it off and in the water in 3 minutes or less.

 

[healhustler]

The dink naturally sits in the curve of the davit. I also use cross ratchet straps to suck it in nice and tight when I am on open ocean. Most of the time it just hangs and I can have it off and in the water in 3 minutes or less.

You must’ve figured it right the first time Sea-Duction. Bligh Has some good points. Almost everything I’ve engineered for my boat, there came the predictible (but not perfectable) details with each design that were only realized after some accute observation in various sea conditions. Even overbuilt designs revealed weaknesses down the line somewhere. Your platform reinforcement below does a nice job of distributing the loads.

 

[Sailor of Fortune]

that looks good ASD. I like any davits that get the tender above and off the swim platform. Yours looks heavy duty.

 

[jimL]

Hi all, This post has been interesting as we all have different requirements and configurations. We're looking for any dinghy davit ideas from owners or former owners of a Mainship 430 aft cabin trawler. The boat has an integrated step in the swimg platform that needs a slight work around. Any pics other members can post is appreciated.

Happy New Year,

jimL

 

[ranger58sb]

We're looking for any dinghy davit ideas from owners or former owners of a Mainship 430 aft cabin trawler. The boat has an integrated step in the swimg platform that needs a slight work around. Any pics other members can post is appreciated.

Can't remember if I posted about it before...

See here: JATCO Marine Products - Online Catalog

FWIW, our is their original Trillogy Dinghy Lift -- not "davit" and not "cradle" -- and it works well enough. (Trillogy is not a mis-spelling; the engineer's name is Joe Trillo.)

Not obvious in their pics is that the systems designed for heavier weights don't depend entirely on the swim platform for support. There's available additional bracing from dinghy mount directly to transom, underwater...

IIRC, ours is the 450 version, and so incorporates two additional bracing struts like that. We mounted it all in a cantilever position, so we can walk between transom and dinghy. It's pretty much a one-handed operation to bring the ~250-lb dinghy/motor aboard using the manual winch.

-Chris

 

[PiperG]

Are you happy with whaler set up?
I am wanting to use stern davits for my whaler but concerned it will put too much strain on stern.

We have a Nick Jackson davit on our stern. Electric wench and does a great job. Fast up and down. We carry a 12' Boston Whaler on it with a 40 HP merc. Personally I think the boat (too big for a dinghy) and motor are over kill, but it came with our trawler when we purchased her last summer.

The plus to this davit:
Very strong.
Lifts a heavy load securely and fast
Keeps the dinghy weight off the top of the aft deck cover

Disadvantages:
Takes up the swim platform with or without the boat on it.
Expensive to buy and mount

My last boat had a 9 ft Livingston Dinghy on a Weaver davit system.
It worked great!

 

[boiler81]

Console RIB on Mainship 34 Trawler

Newbie buying a 2009 34 Mainship Trawler. I am considering a Sea Wise Hydraulic davit system with a 10ft (310) console dinghy and 25hp outboard, similar to pictured. I figure the RIB/Motor combination should weigh in at 375-400lbs.
Don't see many console RIB's used on Trawlers.

Is this too much weight for a bolt-on swim platform, without modification?

Will this added stern weight significantly affect bow angle at displacement speed?

 

[mvweebles]

Newbie buying a 2009 34 Mainship Trawler. I am considering a Sea Wise Hydraulic davit system with a 10ft (310) console dinghy and 25hp outboard, similar to pictured. I figure the RIB/Motor combination should weigh in at 375-400lbs.

Don't see many console RIB's used on Trawlers.



Is this too much weight for a bolt-on swim platform, without modification?



Will this added stern weight significantly affect bow angle at displacement speed?

Looks like the Sea Wise davit weighs in around 115 lbs plus whatever install materials. Call it 125 lbs - about the same as a 25hp outboard. So you're adding about 500 lbs at the end of the swim step. You will definitely notice it, though less at slow displavement speeds than at higher displacement speeds. Mainship 34s seem to top-out at 15-18 kts - that may not be possible with that much weight that far back, but perhaps others with specific MS34 experience could comment.

As far as CC dinks on smaller boats, I have a bias against for two reasons. Complexity, and storage. Sitting two people side by side on a 310 is tight, adding gear, groceries, or another couple passengers is tight too. Also, we run-up on beaches quite a bit. A heavy dink is difficult to impossible. So you have to anchor it in shallow water which is rarely something you can leave unattended. What should provide mobility and freedom becomes a hindrance. But really depends on your cruising style. For those who cruise to marinas, a CC is nice to cruise around harbors.

If your heart is set on a CC in the 310 size, Highfield makes a slick console that is pretty compact and presumably lightweight. Picture attached.

Good luck.

Peter

 

[Seevee]

Looks like the Sea Wise davit weighs in around 115 lbs plus whatever install materials. Call it 125 lbs - about the same as a 25hp outboard. So you're adding about 500 lbs at the end of the swim step. You will definitely notice it, though less at slow displavement speeds than at higher displacement speeds. Mainship 34s seem to top-out at 15-18 kts - that may not be possible with that much weight that far back, but perhaps others with specific MS34 experience could comment.

As far as CC dinks on smaller boats, I have a bias against for two reasons. Complexity, and storage. Sitting two people side by side on a 310 is tight, adding gear, groceries, or another couple passengers is tight too. Also, we run-up on beaches quite a bit. A heavy dink is difficult to impossible. So you have to anchor it in shallow water which is rarely something you can leave unattended. What should provide mobility and freedom becomes a hindrance. But really depends on your cruising style. For those who cruise to marinas, a CC is nice to cruise around harbors.

If your heart is set on a CC in the 310 size, Highfield makes a slick console that is pretty compact and presumably lightweight. Picture attached.

Good luck.

Peter View attachment 131722

Peter,
What is a CC? If you mean center console, that's not what the Highfield is. It's a side console, which is much better. However, I agree, I'm not a fan of dinghy center consoles.


I have a East Marine Godiac, which is very similar to the Highfield. Weighs in at 310 lbs with motor. Is comfy for two but not for big folks.





My Weaver Lever is about 60 lbs which I have removed for a larger dink, but worked very well with my original West Marine dinghy. This was on a Mainship 430.


On my Mainship 400, which is very similar to the 34, I had a AB dinghy that I hoisted up to the back of the flybridge, however a bit lighter, no console and smaller motor. No affect on performance.


I'd think 400 lbs of dinghy and lift wouldn't be an issue with the 34 and the Weaver or similar hydraulic lift would be super easy and convenient. However, would be great to hear from a 34 owne, if one would comment.

 

[Seevee]

Here's the Godiac 320 that I have:


Comfy for two and cruises in the 20 to 25 mph range, can hold 4, plenty of room for groceries. And the console makes it very easy to handle.

 

[mvweebles]

Peter,
What is a CC? If you mean center console, that's not what the Highfield is. It's a side console, which is much better. However, I agree, I'm not a fan of dinghy center consoles.


I have a East Marine Godiac, which is very similar to the Highfield. Weighs in at 310 lbs with motor. Is comfy for two but not for big folks.





My Weaver Lever is about 60 lbs which I have removed for a larger dink, but worked very well with my original West Marine dinghy. This was on a Mainship 430.


On my Mainship 400, which is very similar to the 34, I had a AB dinghy that I hoisted up to the back of the flybridge, however a bit lighter, no console and smaller motor. No affect on performance.


I'd think 400 lbs of dinghy and lift wouldn't be an issue with the 34 and the Weaver or similar hydraulic lift would be super easy and convenient. However, would be great to hear from a 34 owne, if one would comment.

My caution was putting that weight at the end of a swim platform, a lever-arm that would hinder the boat from getting over the hump and on-plane. Hoisting to a boat deck where the weight is more centered would have much less effect. But as you say, best would be someone with more direct experience with a MS34 (or similar) which I do not have.

Yes, CC was shorthand for center console. Better would have been generic console. I had not heard of Godiac. The side console on this and rhe Highfield is really cool. Good idea.

My personal preference is old-school tiller steering in this size range. My AB310 AL with 20hp Tohatsu is about 240 lbs wet and can be fairly easily dragged up a beach beyond the tideline. Not important to everyone.

Peter

 

[rslifkin]

I'd personally consider 300+ lbs of dinghy pretty heavy for a 34 foot boat. In my mind, a super heavy center console RIB doesn't start to make sense until you've got a pretty big boat that can carry a 13 - 15 foot dinghy easily.

Weight wise, our dinghy is about 260 lbs in the davits (assuming a full tank of gas, oars and anchor in the dinghy, etc.). I wouldn't have minded giving it a bit more power than the 6hp that's on there, but I didn't want any more weight (the lightest bigger engine would add another 25 lbs, and that's assuming it didn't lead to wanting a bigger gas tank).



I can't say I've noticed any performance penalty from the dinghy. It likely slows us down just a hair at displacement speed (due to dragging more submerged transom through the water), but it definitely has no noticeable effect at planing speeds. The only downside is having to be careful with it getting in and out of a slip. We're 12'6" across the top of the transom and the dinghy is 12'1" without the outboard. So about 12'8" with the outboard turned sideways.

 

[OldDan1943]

In heavy seas, remember the bounce factor. It will put a strain on the swim platform

 

[koliver]

I bought my Caribe DL12 used. The PO used it on a SeaWise davit system.
The Caribe manual says empty weight is 434 lb and the Honda 40 book says that outboard weighs 214 lb. Add a full 50l fuel tank 81 lb, a battery 15 lb, the usual collection of anchor 10 lb, rode, electronics, fire extinguisher, life jackets, etc. that will stay in the dinghy when on the davits and your weight goes up to over 750 lb.
For good reasons, the SeaWise lists capacities at 450 lb for the manual system and 650 for the electric system.
My Dinghy shows the effects of overloading that system. The stern attachment points on this particular dinghy show failure of the fibreglass, cracks that go all of the way through the structure.
If your installation is on a swimgrid that is bolted onto the transom, you need to reinforce the attachment to take the forces that will test it, especially if your boat planes.
Some SeaWise installations are very well engineered, but I have seen many that are simply a bolt on, with no attention paid to the strength of the underlying swim grid. Since they also attach the dinghy to their system, you need to pay attention to the places on your dinghy that will take the brunt of the punishment your dinghy will receive and be sure those places get any reinforcement they need.
The forward placement of SeaWise braces in your dinghy may take up space that makes passenger placement uncomfortable, so unless you add a quick release so that the braces can be removed, you may find your dinghy is no longer as useable as it should be. Also pay attention to the hooks that remain on the dinghy when it is off the davits, as on many dinghies, those are placed where they will abrade your hull if left to float around, so must be fendered off at all times.

 

[JTMWanderlustToo]

Dinghy Davit

Got our Dinghy Davit system completed a couple weeks ago. here are a few picture and a business card from the person (Dave Miller) that completed it.

 

[Comodave]

We added a 63” extended swim platform last winter. It projects out about 26” from the old swim platform. It is overlaid on top of the old platform which is part of the hull and deck. The swim platform extension manufacturer said to put 3 struts under the extension and just screw them into the transom. I didn’t feel comfortable with that plan. I put 4 struts on. I had 4 4”x1/4” thick discs made out of 316S/S. I had 2 1/4” holes to line up with the holes in the struts. I had the holes countersunk on the transom side. Put a 1/4” bolts thru the discs from the front to make studs for the holes in the struts. I also had 8 holes for #10 screws drilled in the discs to screw into the transom. Then slathered 5200 on the front of the discs and screwed the discs to the transom. Then used the studs to bolt the struts to the transom. It is extremely solid. I couldn’t access the inside of the transom to thru bolt the struts so this was my next best idea on how to secure the struts to the transom. In your case I would add several struts to support the back end of the platform. If you can access the inside of the transom just thru bolt the struts but if you can’t access the inside then add some discs and bolt the struts to them.

We put a Seawise davit on a previous boat and loved it. Very well made and made launching and recovering the dinghy a cinch. Very good customer service.

 

[boiler81]

Thanks for all the great replies and suggestions.

I didn't fully explain my circumstances and why I wanted a console RIB and davit system similar to the picture. The admiral and I are both seniors, love boating, but my wife has had double knee replacements, is not height to weight proportional, and is not agile enough to comfortably board a dinghy, unless it's secured to limit motion upon entry/exit and has something higher than the RIB tube handles to grab on to when boarding and running. The dinghy and davit system also need to retain access to the transom door on the starboard side for access at the dock.
So, I understand my trawler with single 380HP Yanmar may not "get over the hump" anymore, but I plan on cruising at 7-10 knots in protected waters of the Puget Sound, San Jaun's, and Gulf Islands.
My concern is to not damage the dinghy, Trawler swim step or transom, and not to make the vessel unseaworthy due to added stern weight.
I think some additional transom brackets and/or reinforcement will be needed, but this should meet my needs if there is no fatal flaw in this setup.

 

[mvweebles]

Thanks for all the great replies and suggestions.

I didn't fully explain my circumstances and why I wanted a console RIB and davit system similar to the picture. The admiral and I are both seniors, love boating, but my wife has had double knee replacements, is not height to weight proportional, and is not agile enough to comfortably board a dinghy, unless it's secured to limit motion upon entry/exit and has something higher than the RIB tube handles to grab on to when boarding and running. The dinghy and davit system also need to retain access to the transom door on the starboard side for access at the dock.
So, I understand my trawler with single 380HP Yanmar may not "get over the hump" anymore, but I plan on cruising at 7-10 knots in protected waters of the Puget Sound, San Jaun's, and Gulf Islands.
My concern is to not damage the dinghy, Trawler swim step or transom, and not to make the vessel unseaworthy due to added stern weight.
I think some additional transom brackets and/or reinforcement will be needed, but this should meet my needs if there is no fatal flaw in this setup.

Sounds like you've thought it through. A good plan.

Given Koliver's story a few posts up-thread, I would definitely make sure the swim platform is adequately braced.

Peter

 

[Comodave]

If you need struts you might try swimplatforms.com. That is where I got my extension and the struts came with it. They may sell you the struts you need. They made mine to the length I needed.

 

[Blue Tortuga]

I also owned one of these on my previous boat.
Very easy to use . WWW.dinghycaddy.com

I second dingy Caddie. I’ve had mine 2 years on my Mainship 400. 11’ inmar RIB with 20hp with euro console. Works great.

 

[PVL]

ForeSpar

I have a 2003 MainShip 30 II. Swim platform is 24”. In my opinion, the best Davit system for a dinghy with that set-up is a ForeSpar type system. Roll on type Davits like Hurley do not work. I’ve tried them, they’re terrible. No room to tie anything down. The boat came with a ForeSpar Nova and I’ve gone back to that. Be sure your dink is much shorter than your beam. My dink is 8’8”. beam of the MS 30 is 10’3”. Outboard is 30 lbs. it’s simple to just drive in, hook up to the lifting bridles, get off, hoist it up, put a few stabilizing lines on for lateral movement, and take off. You have to figure out the distance of the arms, where you mount the lifting bridles, etc.