2006 Hunter 25 - Swim Platform Stress Cracks

[robm]

Hi all,

Earlier this summer, I noticed some faint gel coat cracks at various points across the swim platform of our 2006 Hunter 25. I thought it might be surface / cosmetic due to age and flexing, but I have seen more cracks appear, and some progression of existing cracks over the past few weeks. I know the right thing to do is to have the above repaired properly, but that would put an end to this summer’s sailing season unless I find a shop that can fix this ASAP (am not having much luck with this option so far).

Here’s a summary of what I have observed for stress cracks. See attached photos for items 1 and 2, below.

Stress Crack Locations:

1. Inboard forward motor mount hole. This location is where the cracks have progressed the most. There are four bolts for the motor mount. If one is standing on the swim platform, looking forward and down from above the mount, the one with the cracks would be the upper left of the 2 x 2 bolt pattern.
2. Rudder mount. These are faint long cracks that run from the aft edge of the swim platform forward and around the entire raised rudder mount “hump”, and one crack that runs more or less vertically down on the port side (rudder perspective) of the rear vertical part of the swim platform.
3. Forward edge of recessed area of the telescoping swim platform ladder. These don’t appear to be structural, and may be related to someone banging the ladder down without it being fully retracted.

Additional Details:

• If I attempt to move the Tohatsu 9.8 fore and aft, I can see a small amount of flexing near the stress crack. This makes sense, of course.
• There are places on the swim platform where I can feel some slight flexing and crackling noises when I stand on them. Not a good noise, for sure.
• I haven’t had time to crawl into the aft compartment to take a look from underneath the swim platform, but I’m going to do this sometime in the next several days.


Questions:

1. Is the swim platform reinforced other than the embedded aluminum bars for the motor mount bolts? Am wondering if there is marine plywood in between the fiberglass layers. I may be able to determine this when I look underneath it, but I haven’t been able to find this information online.
2. The big question that is difficult to answer without seeing the above in person: Is what I’m describing dangerous enough for us to stop using our boat until this issue is addressed? If the swim platform is completely reinforced with plywood or other core material from side to side, I would be a bit less worried about a catastrophic failure of the motor mount. My immediate action would be to focus on preventing water intrusion through the cracks for a few more weeks until we can get her to a repair shop.

Apologies for the long post. Wanted to provide enough details to see if anyone could provide feedback about the situation. And, to be clear, If there is any risk beyond “unlikely to fail catastrophically”, then she’ll remain on the hard until repaired.

Thanks for any information anyone can provide.

Rob

 

[Ralph Johnstone]

Hi @robm and welcome to the site.

Your write up is excellent compared to the usual "my boat don't float, what's up ?" sort of thing we see here.

To get a better idea of the vectors ( force acting in a direction) acting on the components we see in your pictures, would it be possible to get pictures from further back so we can see what's what ? Also, do you have a graphic editing app so you can write on your pics as to what we're seeing and where the forces are originating ? Even a video on YouTube could give a good idea with your pointing out what is happening at each failure.

In the first three pictures I see, it appears that you have some large forces acting on unreinforced parts of the boat. These are not spider cracks but structural cracks. IMO and depending on where they are, they may require attention much sooner rather than later to avoid either injury or far greater expense down the road. Pictures with written detail will go a long way to getting an idea of what's happening.

 

[Crazy Dave Condon]

First. Do you trailer your boat a lot?
Second, if you do, is the motor tied upward to keep it from bouncing?
Third, can you take pictures of the back inside the boat?
Fourth, any previous damage from an accident?

 

[Crazy Dave Condon]

Do you have a picture of the boat sittting on the trailers? I am looking for pictures of the hull sitting on the bunk boards particularly on the rear to see they are indenting the hull

 

[Crazy Dave Condon]

No on wood or balsa in the deck. Only divinacell. Water penetration? Photo please of the cockpit from the rear of the boat

 

[robm]

Hi Ralph and Dave,

Thanks for your followup messages.

Re: the information and photos you requested, today is really busy at work, so I won’t have time to reply in detail until tonight. As for the photos, looks like Friday evening is the first time I will be able to get to the boat to snap some additional shots.

Appreciate your time and insight. Looking forward to hearing what you have to say after I provide the additional information.

Rob

 

[Crazy Dave Condon]

@robm

The boat had wheel steering as an option. I am inquiring if there is wood in the cockpit as a strengthener in between the fiberglass.
Pressurizing the cabin and brushing the deck with a brush and soapy water will detect air bubbles showing where leaks are in the deck. Look for any signs of water seepage inside toward the rear when you go to the boat

 

[robm]

First. Do you trailer your boat a lot?

The boat sits rigged on its trailer about 50' from a launch ramp when not in the water. It is trailered to and from its summer location at the beginning and end of the season, respectively.

Second, if you do, is the motor tied upward to keep it from bouncing?

It is not tied up; didn't realize this was a best practice, but I wish I had. Will do it going forward, for sure.

Third, can you take pictures of the back inside the boat?

Yes, I can do this, but not until Fri night or over the weekend (schedule is a bit uncertain due to some family events).

Fourth, any previous damage from an accident?

No accidents or damage. We bought the boat in 2013, and it's been fine until this year.

 

[robm]

Do you have a picture of the boat sittting on the trailers? I am looking for pictures of the hull sitting on the bunk boards particularly on the rear to see they are indenting the hull

Will shoot the requested photos this weekend.

No on wood or balsa in the deck. Only divinacell. Water penetration? Photo please of the cockpit from the rear of the boat

Re: no wood or balsa, thanks.

Re: water penetration, none that I am aware of. The cracks and the expansion of them are a recent occurrence, and we've had very little rain this summer. Can check when I crawl into the aft compartment this weekend, and will snap some photos of the underside of the swim platform.

 

[robm]

@robm

The boat had wheel steering as an option. I am inquiring if there is wood in the cockpit as a strengthener in between the fiberglass.
Pressurizing the cabin and brushing the deck with a brush and soapy water will detect air bubbles showing where leaks are in the deck. Look for any signs of water seepage inside toward the rear when you go to the boat

Our boat has wheel steering.

Re: pressurizing the cabin, I'm trying to figure out how I would seal it well enough to accomplish this. Perhaps taping all openings and gaps?

 

[robm]

Hi @robm and welcome to the site.

Your write up is excellent compared to the usual "my boat don't float, what's up ?" sort of thing we see here.

Thanks, Ralph. Writing technical problem descriptions has been part of my professional life for a long time.

To get a better idea of the vectors ( force acting in a direction) acting on the components we see in your pictures, would it be possible to get pictures from further back so we can see what's what ? Also, do you have a graphic editing app so you can write on your pics as to what we're seeing and where the forces are originating ? Even a video on YouTube could give a good idea with your pointing out what is happening at each failure.

I can shoot some additional photos this weekend, and mark them up. The motor mount bolt with the cracks just forward of it in the photos is mostly in tension; should be obvious in the pending photos. And yes, I can mark them up.

In the first three pictures I see, it appears that you have some large forces acting on unreinforced parts of the boat. These are not spider cracks but structural cracks. IMO and depending on where they are, they may require attention much sooner rather than later to avoid either injury or far greater expense down the road. Pictures with written detail will go a long way to getting an idea of what's happening.

Yes, they look structural to me, too. Any comments that imply otherwise are my wishing that was not the case.

Will post an update this weekend after I shoot new photos and annotate them per your request.

Thanks!

 

[Ralph Johnstone]

Re: pressurizing the cabin, I'm trying to figure out how I would seal it well enough to accomplish this. Perhaps taping all openings and gaps?

Very gently. Remember:

Force = Pressure X Area

and you have a very large area on the interior cabin. To much pressure and you'll have liftoff.

 

[Crazy Dave Condon]

Close up the boat. Tape a large piece of of plastic over the entire companionway and put a slit in it for a leaf blower. Tape plastic to leaf blower and turn on. Old marina yard trick that works to find leaks where air bubbles out

 

[Crazy Dave Condon]

Look at the bolt pattern holding the wheel inside the boat for any water stains and see if the nuts are loose.

I am going to my source about the wood in deck and will advise. As for the motor mount and ladder, check tightness of bolt and nuts. The boat was made 16-17 years ago and things do give

 

[robm]

Quick update: Shot a bunch of photos Sun afternoon. Will select a subset and mark them up later this evening.

 

[Crazy Dave Condon]

@robm

let me know when you do

 

[robm]

Hi @Crazy Dave Condon and @Ralph Johnstone.

Sorry for the delay in getting the photos ready to post; it's been a busy week in and out of work.

I shot dozens of photos on Sunday, and selected a representative subset to export for posting. See attached for an initial round of exterior and interior shots. Happy to post more, if requested.

Rob

 

[Sailavie1]

I have the same boat, so this is very interesting info. So far no cracks on mine but I will tie the motor up in the future.

 

[Crazy Dave Condon]

need to know if trailering a lot and if so is the motor tied upward to keep it from bouncing? Two or four stroke engine and hp? Check the backing plate for the rudder inside of boat advising if marine ply only or what. Picture of rear of cockpit showing wheel steering too.

 

[robm]

need to know if trailering a lot and if so is the motor tied upward to keep it from bouncing?

Trailering to summer location at start of season, and vice-versa at end of season. Alas, motor has not been tied up for transport in the past.

Two or four stroke engine and hp?

Four-stroke Tohatsu 9.8.

Check the backing plate for the rudder inside of boat advising if marine ply only or what.

Uncertain. See one attached photo for another angle of what I was able to capture last weekend (I have others, but they haven't been exported and resized yet).

I'll have to pull the starboard battery to get back far enough to take closer shots of the rudder plate and probe its material to see what it is. Can do that later today, hopefully.

Picture of rear of cockpit showing wheel steering too.

I may have a shot from the rear of the cockpit; will check later. I did take some of the exterior view of the steering tunnel and the interior bolt ends + nuts for the steering mount inside the aft compartment, but didn't export the tunnel shots for some reason.

See attached for shots of the interior port/starboard steering + pedestal bolts